Contamination Analysis

Gideon Analytical Laboratories received several RY4S-UAC110-120V power relays for failure analysis. A relay is an electrically operated switch. Many relays use an electromagnet to operate the switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a separate low-power signal, or where several circuits must be controlled by one signal. Relays are used to control a high power or high voltage circuit with a low power circuit. The low power is isolated from the high power circuit. The RY4S-UAC110-120V power relays have 4PDT contact configuration, 5A contact current, quick connect relay terminals, and silver contact material. Their coil resistance is 4.29kohm. When given the RY4S-UAC110-120V power relays, we were to tasked with determining the stuck core/contact cause.

Gideon Analytical Laboratories received a TI TMS320F28335PGFA Digital Signal Processor for failure analysis. Digital Signal Processing applications include audio and speech processing,sonar,radar, and other sensor array processing,spectral density estimation,statistical signal processing,digital image processing, among many others. The TI TMS320F28335PGFA features high-performance static CMOS technology, a 32-bit CPU, 16 x 16 and 32 x 32 MAC operations, and Harvard bus architecture. It has up to 88 individually programmable, multiplexed GPIO pins with input filtering. We were advised to pay special attention to pins 141 and 148 because they were possibly nonfunctional in operation.

Gideon Analytical Laboratories received several Murata Electronics GCM21BR70J106KE22L Multi-Layered Ceramic Capacitors (MLCCs) for failure analysis. An MLCC consists of a number of individual capacitors stacked together in parallel and contacted via the terminal surfaces. The starting material for all MLCC chips is a mixture of finely ground granules of paraelectric or ferroelectric raw materials, modified by accurately determined additives. The Murata Electronics GCM21BR70J106KE22L has a capacitance of 10 uF, a DC voltage rating of 6.3 VDC, has an XR7 dielectric, and has an SMD/SMT termination style. It has a minimum operating temperature of -55 Celsius and a maximum operating temperature of 125 Celsius. The goal was to determine why these MLCCs were failing, and while we did discover why, that is not the only thing we uncovered.

Gideon Analytical Laboratories received four Vishay CRCW2512220RJNEG thick film chip resistors to be analyzed. Thick film resistors are the most used resistors in electrical and electronic devices. The resistive material is a special paste with a mixture of a binder, a carrier, and the metal oxides to be deposited. These Vishay CRCW2512220RJNEG resistors thick film chip resistors feature stability at different environmental conditions and 2mm pitch packaging option for 0603 sizes. Typical applications for these chip resistors include automotive, telecommunications, and industrial. Its resistance range is 1 and 10 ohms. All of the Vishay CRCW2512220RJNEG thick film chip resistors tested open. The goal was to try to diagnose these failures.

Gideon Analytical Laboratories received six United Chemi-Con KMG series 400V 22uF 6U capacitors for the specific purpose of determining whether or not they had the presence of chlorides.

The analysis was performed using SEM-EDS. The SEM-EDS system gave elemental analysis in relation to the intensity of the element at a specific wavelength or energy level (Kev). SEM-EDS is an analytical technique used for the elemental analysis or chemical characterization of a sample. It relies on an interaction of some source of X-ray excitation and a sample. Its characterization capabilities are due in large part to the fundamental principle that each element has a unique atomic structure allowing a unique set of peaks on its electromagnetic emission spectrum.Theelectron-volt is used to measure energy. It is defined as the amount of energy an electron gains after being accelerated by 1 volt of electricity.

Gideon Analytical Laboratories received several high-intensity discharge lamp (HID) assemblies for determination and cause of a white powder-like substance on the inside of the lens housing. The white powder diminishes the reflective properties of the light and overall effectiveness. HID lamps are a type of electrical gas-discharge lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube. The three-man types of HID lamps are mercury, sodium, and metal halide. These lamps are known for their high efficiency at turning electricity into light and their long rated life. HID lamps require a ballast in order to generate the initial surge of electricity needed to start them and to regulate their power during normal operation.

Gideon Analytical Laboratories received one section of the anode electrode to identify the black marking on the copper foil. This anode electrode is used in Lithium-ion batteries. A Lithium-ion battery is a type of rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging. Lithium-ion batteries use an intercalated lithium compound as one electrode material, compared to the metallic lithium used in a non-rechargeable lithium battery. The electrolyte, which allows for ionic movement, and the two electrodes are the constituent components of a lithium-ion battery cell. The goal was to conduct an electronic failure analysis to identify the black marking on the copper foil.

Gideon received ultra precision calibration resistors. These resistors have a tolerance of .1%. The ultra precision thin film resistors are designed for high precision circuitry. They have excellent stability and reliability over the operating temperature range and low TCR characteristics.

The resistors were running about .3 to .4 ohm too high.

As one can see by the above table, after the 5th test, the resistor on the first PCB recovered. The second PCB resistor did not, therefore, the resistors were taken apart to find the cause of the higher resistance.

Gideon Analytical Laboratories received several screws to identify whether or not they were the source of carbon disulfide and sulfur dioxide, which were attacking some Buna-N O-rings.  O-rings are a mechanical gasket in the shape of a torus; it is a loop of elastomer with a round cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface. The O-ring may be used in static applications or in dynamic applications where there is relative motion between the parts and the O-ring. Dynamic examples include rotating pump shafts and hydraulic cylinder pistons. Nitrile, also commonly referred to as Buna-N or NBR, is a copolymer of Acrylonitrile and Butadiene. Nitrile is the most commonly used elastomeric material for molded and extruded products. This material offers relatively low cost, good mechanical properties, and resistance to many common oils, fuels, and lubricants. NBR has poor resistance to weathering, sunlight, and ozone so it is best used in enclosed environments where parts are not exposed to the elements. For this job, the goal was to identify the source of the carbon disulfide and sulfur dioxide that was on the screws.

Gideon Analytical Laboratories received a printed circuit board (PCB) with suspected failing multi-layered ceramic capacitors (MLCC). Multilayer ceramic capacitors are fixed value capacitors in which ceramic the material acting as the dielectric. It is made up of two or more alternating layers of ceramic and a metal layer acting as the electrodes. There are various types of materials that could function as the dielectric in a capacitor, for example, glass, porcelain, paper, or mica. Each PCB has four suspected failing MLCCs, and the goal was to determine the cause of these failures.

Gideon Analytical Laboratories received two valves with failed printed circuit boards (PCBs) and corrosion inside the housing. The goal was to determine what the corrosion was and why the PCB failed. A printed circuit board mechanically supports and electrically connects electronic components using conductive trace lines, pads and other features etched from copper sheets laminated onto a non-conductive substrate. The boards are made from glass reinforced plastic with copper tracks in the place of wires. Components are fixed in position by drilling holes through the board, locating the components and then soldering them in place. The copper tracks link the components together forming a circuit. PCBs are used in all but the simplest electronic products. They are a quintessential part of the electronics industry. With decades of experience working with PCBs and advanced knowledge in electrical engineering and chemistry, this proved to be a case that was easy to solve.

Gideon Analytical Laboratories received a flex circuit with a mystery corrosion on the polyimide and silicone pressure sensitive adhesive (PSA). There was corrosion by-product, and the silicone adhesive appeared more like a gelatinous material than a tactic PSA. Contrary to popular belief, flex circuits are not training for a future bodybuilding competition, they are a technology for assembling electronic circuits by mounting electronic devices on flexible plastic substrates, such as polyimide, PEEK or transparent conductive polyester film. Additionally, flex circuits can be screen printed silver circuits on polyester. Flexible electronic assemblies may be manufactured using identical components used for rigid printed circuit boards, allowing the board to conform to the desired shape, or to flex during its use. A polyimide is a polymer of imide monomers, and have been in mass production since 1955 due to their diverse applications. The goal was to figure out what the mysterious corrosive substance on the polyimide and silicone PSA on the flex circuit was.

Gideon Analytical Laboratories received two PCB assemblies upon which were several failing Vishay CRCW1210-HP-e3 surface mount (SM) resistors. Surface mount technology (SMT) is a method for producing electronic circuits in which the components are mounted or placed directly onto the surface of printed circuit boards (PCBs). An electronic device so made is called a surface-mount device (SMD). In the industry, it has largely replaced the through-hole technology construction method of fitting components with wire leads into holes in the circuit board. The goal was to determine the cause of the failing Vishay CRCW1210-HP-e3 SM resistors.

Gideon Analytical Laboratories received several lighting tracks for failure analysis. They all had what appeared to be arcing which caused severe copper pitting, melting of the Noryl, and distortion of the power bus bar. The neutral bus was also pitted but not nearly as bad as the power rail. Electrical arcing is an electrical breakdown of a gas that produces an ongoing electrical discharge. The current through a normally non-conductive medium such as air produces a plasma; the plasma may produce visible light. An arc discharge is characterized by a lower voltage than a glow discharge, and it relies on thermionic emission of electrons from the electrodes supporting the arc. An arc between two electrodes can be initiated by ionization and glow discharge, as the current through the electrodes is increased. The breakdown voltage of the electrode gap is a function of the pressure, the distance between electrodes and the type of gas surrounding the electrodes. When an arc starts, its terminal voltage is much less than a glow discharge, and current is higher. An arc in gases near atmospheric pressure is characterized by visible light emission, high current density, and high temperature. NORYL resins are a rare example of a homogeneous mixture of two polymers. Most polymers are incompatible with one another, so tend to produce separate phases when mixed. The two polymers compatibility in NORYL resins is due to the presence of a benzene ring in the repeat units of both chains. The goal was to determine why there was electrical arcing on these lighting tracks.

Gideon Analytical Laboratories received three electrolytic capacitors that were failing in the field. A capacitor stores electrical energy. They have two terminals separated by some type of insulating material, known as a dielectric. Usually, these dialectics are metal plates and the dielectric is made of materials like ceramics, mylar, or glass. Electrolytic capacitors are a type of capacitor that uses an electrolyte as one of its plates to achieve a larger capacitance per unit volume. The storage potential of a capacitor is known as capacitance and is measured in farads, and since most capacitors are generally small, micro farads are the most often used measurement of capacitance. All of these capacitors measured a short across the respective terminals. The goal was to determine the cause of failure.

Gideon Analytical Laboratories received one printed circuit board (PCB) with an open in the plated through hole (PTH). A printed circuit board mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate.  Advanced PCBs may contain components - capacitors, resistors or active devices - embedded in the substrate. PCBs are used in all but the simplest electronic products. Plated through holes are a type of through-hole technology, which refers to the mounting scheme used for electronic components that involve the use of leads on the components that are inserted into holes drilled in PCBs and soldered to pads on the opposite side either by manual assembly or by the use of automated insertion mount machines. The goal was to determine whether or not contamination caused the open in the via.

Gideon Analytical Laboratories, Inc. received on Vishay ES2D rectifier on a PCB. The initial condition and observation were that the diode had a conformal coating on a small circuit board in which when tested on a curve tracer had excessive leakage current across the junction and caused the PCB to fail in the application.

Rectifiers are primarily used for conducting in one direction and blocking in the other. The Vishay ES2D is an ultra-fast rectifier, which means the reverse recovery time should be less than 100 ns. Rectifiers are primarily used for power or signal conditioning in a variety of applications. This can range from high power output rectifier applications to low power switching rectifier requirements. They can be used for clamping networks on SMPS, dampening and modulating diodes on deflection circuits in CRTs, or freewheeling diodes on inductive loads etc.

Gideon Analytical Laboratories received two 153D8496G1 printed circuit boards (PCBs)for failure analysis. A PCB mechanically supports and electrically connects electronic components using conductive tracks, pads, and other features etched from copper sheets laminated onto a non-conductive substrate. Some of the electronic components that might appear on a PCB include semiconductors like diodes or transistors, discharge devices, power sources, resistors, and capacitors. The153D8496G1 circuit card assembly has 6 capacitors, 20 resistors, and 18 semiconductors all mounted to a printed wiring board. The capacitors on both153D8496G1 PCBs were open, and as a result of the leads disintegrating in the presence of voltage and flux. The goal was to find the reason why these capacitors on the PCBs were failing.

Gideon Analytical Laboratories received several Synchronization Supply Units (SSU); the covers of the SSU had contamination on them. Synchronization Supply Units are important in modern digital telecommunications networks because components of the network need to be accurately synchronized. The SSU ensures reliable distribution of the time signal kept by a Primary Reference Clock (PRC). There were stains located near the Capacitor -input filters (Pi filters) on both sides of the cover of the SSU. Capacitor-input filters are a type of electronic filter used to remove unwanted frequencies from a signal. They are called “Pi” filters because of their resemblance to the Greek letter “Pi”. The goal was to perform a chemical analysis of the contamination.

Gideon Analytical Laboratories received several plated steel parts, including coupons, hinges, and shoulder nuts. The goal was to determine if these parts were RoHS compliant. RoHS is short for Directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment; it was initially created by the European Union in February of 2003. To be RoHS compliant, devices have to be free from the following hazardous substances: Lead, Cadmium, Mercury, Hexavalent chromium, Polybrominated biphenyls, and Polybrominated diphenyl ether. There are a number of electronics components that potentially could contain these restricted substances like solders printed circuit boards, lamps and bulbs, batteries, and metal parts. Closely linked to RoHS is the Waste Electrical and Electronic Equipment Directive (WEEE).

Gideon Analytical Laboratories received several failed and several good Shanghai Daido springs for evaluation. Shanghai Daido SP Co makes four types of springs: compression, heavy load, tension, and torsion. Gideon Analytical Laboratories was altered to possible contamination on the failed springs. The goal was to see why these springs were failing.

Failure analysis ensued. SEM-EDS analysis was first utilized to ascertain the elements present within the springs. Micrographs of the first spring pictured a low energy granular type structure with a shiny surface. There were areas that were pitted, and in other areas, severe dissolution of the metal. EDS spectra revealed the presence of chlorides within the nickel and chromium exterior. Micrographs of another spring revealed the decreased presence of nickel. The fourth spring was a catastrophic failure; it had large pits and corrosion was obvious. EDS spectra revealed the presence of chlorides. In summary, pitting was observed on five of the springs, and chlorides were present on these five springs. Corrosion caused cracking, and cracking caused failure.

Gideon Analytical Laboratories received several Bourns Trimpot Trimming Potentiometers for failure analysis. A Potentiometer (known as a pot) is a three-terminal resistor with a sliding contact that forms an adjustable voltage divider. They are widely used for volume control in radio and television receivers. The Bourns Trimpot Trimming Potentiometer 3006P 203 has a standard resistance range of 10 to 5 megohms, the power rating of 400 volts maximum, and is ROHS compliant. Gideon Analytical Laboratories received good and bad units for comparison. The failures were addressed as having higher resistance or open.

Gideon Analytical Laboratories received several GE Aviation 144A9284P4 carbon film resistors for failure analysis evaluation. A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Their purpose is for creating a precise quantity of resistance for insertion into a circuit; they are typically constructed of metal wire or carbon and engineered to maintain a stable resistance value over a wide range of environmental conditions. They are frequently integrated within integrated circuits within the silicon; the resistor changes the voltage or the current in the line. It’s measured in ohms (Ω). There were five working and five failed 144A9284P4 carbon film resistors. The failed resistors exceeded the 2% tolerance designated for this type of carbon film resistor.

Gideon Analytical Laboratories received four Fairchild 74OL6000 field failed Optocouplers along with three good (virgin green dot) devices in which a comparison could be done. The LSTTL input compatibility is provided by an input integrated circuit, with industry standard logic levels. This input amplifier IC switches a temperature compensated current source driving a high speed 850 nm AlGaAs LED emitter. This integration scheme eliminates CTR degradation over time and temperature. The emitter is optically coupled to an integrated photodetector/high-gain, high-speed output amplifier IC. The TTL compatible output has a totem-pole with a fan-out of 10. The CMOS compatible output has an open collector Schottky clamped transistor that interfaces to any CMOS logic between 4.5 and 15 volts. More information on this part can be seen at http://www.alldatasheet.com/datasheet-pdf/pdf/179405/FAIRCHILD/74OL6000.html. Three of the optocouplers were tested in a circuit (the input voltage on pin 2 could be varied from 0 volts to 2.3 volts) and found the output remained low. One intermittent opto functioned in the test circuit, as did the green dotted optos. There was no electrical difference between this “quasi-failed devices” than a good green dotted opto. Next, the optos were tested for leakage current from pin to pin to establish which side of the opto was causing the problem.

Gideon Analytical Laboratories received several liquid-crystal displays (LCDs) that had fading issues; there were five failing LCDs and a good LCD for comparison. An LCD is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals. LCDs are extremely common in electronic devices such as laptops, digital clocks, and watches, pocket calculators, microwave ovens, or CD players. LCDs are also used in televisions and produce a sharp and vivid image. LCDs are can be small, inexpensive to manufacture, and do not draw a lot of power. The LCDs that were received had fading issues on the side closest to the seal. The fading had occurred over time. The goal was to determine the cause of these failures.

Gideon Analytical Laboratories received two surface mount (SM) tantalum capacitors that had internal resistive shorts. Capacitors are passive, two-terminal electrical components used to store energy. They vary in construction, but all have at least two electrical conductors that are separated by an insulator, known as a dielectric. Tantalum capacitors are a type of electrolytic capacitor, which are ubiquitous in electronic circuits. Tantalum capacitors have a high capacitance per volume and weight and are more expensive than any other commonly used capacitor. The goal was to determine the causes of these internal resistive shorts.

Gideon Analytical Laboratories received three samples in polyethylene bottles to develop an analytical procedure for determining chloride using an ion chromatograph. Ion chromatography is a process that allows the separation of ions and polar molecules based on their charge. Using ion chromatography, one can identify concentrations of major anions, including elements like sodium, lithium, calcium, and many others. Aqueous samples are quantitatively measured in the parts-per-million range.

The two solutions were diluted 1:25 with DI water (18.2megaohm) water from a point of use Millipore purification system. The samples were then analyzed by ion chromatography; it was carried out with an instrument that consisted of HP1050 pump and autosampler with a Dionex AMMS suppressor and conductivity detector. Data was captured using an HP Chemstation. Displayed in the table below is the ion chromatograph readings of the respective samples. The picture shows the first sample (in red) at 3.4 PPM and the second sample (in blue) at 35.1 PPM. The results of the ion chromatography revealed the certain presence of chloride; absolute identity was made by spike, subtraction, and standards.

Gideon Analytical Laboratories received four 220 picofarad AVX capacitors for failure analysis. There are a variety of capacitors, including ceramic, aluminum, film, and tantalum, but all serve the same purpose, which is to store electrical charge. They are passive electrical components with at least two electrical conductors separated by an insulator (dielectric). The four220 picofarad AVX capacitors were giving low resistance readings.

Failure analysis ensued. The four 220 picofarad AVX capacitors were inspected for mechanical cracks, which would propagate upon voltage; no cracks were found on the external ceramic. The capacitors were measured and tested on a curve tracer since they had low resistance, otherwise, an IR meter would be used. The current was gradually increased to the point where dendrites would burn out. The resistance was measured again. No change occurred. The capacitors were baked and then retested again; no appreciable change occurred in resistance measurements. These test results indicate there was most likely an internal problem with the capacitor.

Gideon Analytical Laboratories received six pulse transformers, three of which were failures, three of which were reliable. The objective was to determine the cause of the failures and inspect the unused transformers for anything that could contribute to the cause of failures. Transformers are devices that transfer electric energy from one circuit to another, usually with a change in voltage. Pulse transformers are transformers optimized for transmitting rectangular electrical pulses. Ideally, pulse transformer designers try to minimize voltage droop, rise time, and pulse distortion. Gideon Analytical Laboratories conducted a thorough failure analysis on these pulse transformers.

Gideon Analytical Laboratories received several contaminated lead screw assemblies. Also received were three insulin samples, one grease sample, and several new parts making up the lead screw assembly. Lead screws are designed to translate turning/rotary motion into linear motion. The contamination on the shaft of the assembly was primarily concentrated between the bearing and the ball seal. The goal was to identify and determine the cause of the contamination.

Gideon Analytical Laboratories primarily used FTIR and SEM-EDS analysis for diagnostics. FTIR analysis was initially performed using an Analect DS-20 FTIR with an Analect XAD microspectrophotometer equipped with a small chip, high sensitivity MCT detector. The FTIR analysis revealed that the contaminate had a high degree of hydration, oxygen, and salt. The large contamination of salt will tend to migrate towards hydrated substances. The FTIR analysis also revealed that APIDRA was an integral component of the contaminate. SEM-EDS analysis was utilized to determine whether the contaminants were coming from the inherent materials or an outside source.

Gideon Analytical Laboratories received metallurgical corrosion failures from lamp sockets. The materials and the insulation protection was compared to distinguish the difference between the two lamp sockets. The lamp sockets were overheating and melting the wire insulation in the application. These sockets are a type of bi-pin lamp fitting. Bi-pin lamp fittings are for use in incandescent (especially halogen) and some fluorescent lights. MR16 refers to the lamp construction and overall diameter at its largest circumference. The failed socket is pictured below, at left, it showed extensive overheating and melting of the wire insulation.

Gideon Analytical Laboratories received two failed terminal block electrical connectors from two different installation sites. These terminal connectors connect two or more wires to a single connection point, providing a convenient method of connecting electrical wiring without splicing or physically joining the ends.   The two connectors were identical in construction, and both appeared burned out from overpower.

The connector was cross-sectioned and SEM-EDS analysis performed. The screws in the terminal block connector typically are tin plated copper clad iron. Pictures from the first connector, as shown directly below, show the results of extreme temperature elevation with black carbonization and melted housing. Also, the wire was missing in this connector. EDS spectral analysis revealed the inside shaft was plated with tin on brass. A micrograph of the shaft shows many cracks in the plating.

Gideon Analytical Laboratories received several VCSELs (vertical cavity surface emitting laser" with diminished light capacity over time for failure analysis. VCSELs are a type of semiconductor laser diode with laser beam emission perpendicular from the chip surface. The VCSEL has become of great importance in the optical communications field. Gideon Analytical Laboratories was tasked to diagnose the failing VCSELs.

Failure analysis commenced. The devices were tested on a curve tracer to determine whether any junction problems (junction inversion, leakage current, facet oxidation, etc.) were present; there was no leakage current detected by the curve tracer. The VCSELs were then enclosed in a hermetic T0-46 can with a slanted anti-reflective glass coating radiating in the region of 795 nanometers, which is pictured below.

Gideon Analytical Laboratories received three failed Vishay MOC8101 isolating photocouplers for failure analysis. These photocouplers are components that transfer electrical signals between two isolated circuits by using light. Like the MOC8102, MOC8103, MOC8104, and MOC8105, the MOC8101 consists of a consisting of gallium arsenide infrared emitting diode optically coupled to a silicon planar phototransistor detector in a plastic plug-in DIP-6 package (http://www.vishay.com/docs/83660/moc8101.pdf) The MOC8101 were reported to have intermittent function, it was the goal of Gideon Analytical Laboratories to diagnose the cause of these failures.

Gideon Analytical Laboratories received three axial-lead resistors for failure analysis (pictured in the first picture directly below). A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Their purpose is for creating a precise quantity of resistance for insertion into a circuit; they are typically constructed of metal wire or carbon and engineered to maintain a stable resistance value over a wide range of environmental conditions. Gideon Analytical Laboratories was tasked to identify the cause of failure in these resistors.

Gideon Analytical Laboratories received several GVD30601-001 super hyperabrupt junction tuning varactor diodes with a latent failure mechanism over time. A varactor diode is a P-N junction diode that changes its capacitance and the series resistance as the bias applied to the diode is varied. Hyperabrupt tuning varactor diodes offer a large change in junction capacitance over a small tuning voltage range. Varactors are operated in a reverse-bias state, like a Zener diode. Thus, no current flows, but since the thickness of the depletion zone varies with the applied bias voltage, the capacitance of the diode can be made to vary. The depletion region thickness is proportional to the square root of the applied voltage; capacitance is inversely proportional to the depletion region thickness. Thus, the capacitance is inversely proportional to the square root of the applied voltage. The goal was to find the cause if the GVD30601-001 varactor failures.

Gideon Analytical Laboratories received two failed 510K, two used 510K operating for about 3 weeks, and two virgin resistors for failure analysis. A resistor is a component of a circuit that resists the flow of electrical current. It has two terminals across which electricity must pass, and it is designed to drop the voltage of the current as it flows from one terminal to the other. Resistors are primarily used to create and maintain known safe currents within electrical components. The epoxy coating on the failed and used resistor was not as hard as the virgin part. The coating peeled easily and exposed the underlying aluminum metal on the alumina shaft. Therefore, the first suspicion is that something in the process is altering the coating integrity of the epoxy on the resistor. All the resistors were examined for contamination on the epoxy coating by using SEM-EDS to identify any detrimental elements. There is a chloride peak on top of the coating. Normally, chlorides do not attack the epoxy coating nor do they diffuse through the coating to the aluminum metal. As these chlorides were found on the top of the coating, the coating was marked as to the location. SEM-EDS identified chloride. The Si is coming from residual silicates used as binders epoxy coating and the silicone potting material. The chloride was coming from a cleaning product before conformal coating. Gideon Analytical Laboratories can solve all kinds of contamination issues with components and IC. Use Gideon the next time your company needs IC or component failure analysis.

Relays are very susceptible to contamination because the leads are made of copper and vulnerable to corrosion and leakage current if not protected from the environment.

The liquid shown here was thought to have come from the flux residue and, therefore, an organic analysis FTIR was required as opposed to inorganic XRF. However, the liquid was acidic in nature and XRF was employed. The material was a filled, glass fiber reinforced material containing a phosphorus species along with an antimony/bromine fire retardant package. The original formulation likely contained antimony oxide and a poly-brominated organic, such as diphenyl ether or a tetra-bromo BPA polyester or polycarbonate. The bromic acid has leached out of the fire retardant material. This material is not compatible with most electronic circuits or components.

Gideon Analytical Laboratories received four tantalum capacitors identified as failing from two vendors, Kemet (T491B225K035AT) and AVX TAJB225K035RNJ. A tantalum capacitor is a type of electrolytic capacitor. It is constructed of a pellet of tantalum metal as anode, covered by an insulating oxide layer that forms the dielectric (manganese dioxide), surrounded by conductive material as a cathode (carbon with a silver epoxy interface). Tantalum electrolytic capacitors exploit the tendency of tantalum to form a non-conductive protective oxide surface layer. A tantalum capacitor consists of tantalum powder pressed into a pellet shape as one “plate” of the capacitor, with the oxide as a dielectric, and an electrolytic solution or conductive solid as the other “plate”. The dielectric layer thus can be very thin. This gives tantalum capacitors an advantage over electrolytic capacitors in having a high capacitance per unit volume and weight.

Gideon Analytical Laboratories received several samples thought to a contain silicone contaminate that prevented adhesion on the metal substrate. The analysis was performed using micro-FTIR analysis for the presence of silicone in three samples.

The samples were first examined under a microscope to identify the FTIR.

The contaminate is a dimethyl siloxane preventing adhesion.

Gideon Analytical Laboratories can save your company by identifying the materials that cause problems. We have many analytical techniques, instruments and years of experience in the electronic and chemical industries. Call with your analysis.

Several screws were presented to Gideon Analytical Laboratories due to corrosion. The screws were analyzed with SEM-EDS. The micrograph indicates the spot where this screw was analyzed. Chloride was found on the spot where corrosion was found.

Gideon Analytical Laboratories can identify the source and cause of corrosion allowing the customer to implement the corrective action immediately.

Gideon Analytical Laboratories received contaminated rubber seals which prevented the rubber from functioning correctly.

The colorless liquid gave the spectra in Figure 1. This is very similar and matches very well with a spectrum of N-(heptyl-nonyl-undecyl) phthalate, which is shown in Figure 2. This is generically known as a “phthalate ester” which is a liquid similar in appearance to vegetable oil. Phthalates are used primarily in the manufacture of polyvinyl chloride products and used as a plasticizer to create softness and flexibility.

Gideon Analytical Laboratories received three partial boards with four coupling Vishay MKT 1817 63V ERO 0225 film capacitor failures. After electrical measurements and considerable testing, the ESR was found to be the cause of the failure, however, what caused the ESR to elevate?

It was determined the packaging on the capacitor was not adequately protecting the terminal end from the outside environment. Moisture ingress elevated the ESR and with higher ESR, the higher the heat produced in the circuit. This capacitor was a replacement for another capacitor once used in the circuit. This capacitor had higher ESR than its predecessor. Thus, with the higher ESR to begin with, the moisture and ionic ingress through the package and the ripple current being used in the application this lead to thermal failures.

Gideon Analytical Laboratories received a cold rolled steel plate with two corrosion blemishes on the plating. The black corrosion deposition is on zinc plating, which has oxidized with chlorine forming zinc chloride.

The SEM-EDS spectrum shows an excessive amount of chlorine. The chloride is reacting with the zinc. Chlorides are very corrosive to electronic parts, plating, and metals. On copper trace lines the resistance increases, metals discolor, and on aluminum, it acts as a corrosive catalyst causing opens and pitting to metal.

Three lots of capacitors were submitted Gideon Analytical Laboratories for chloride and zinc contamination analysis on the terminal leads of the electrolytic capacitors.

The analysis was performed using an SEM-EDS system giving elemental analysis in relation to the intensity of the element at a specific wavelength or energy level (Kev). Since Kev (energy levels) for specific elements do not change, these are used to identify the elements in the sample.

Below is an EDS of the contamination. The analysis proved the leads had silver, tin and, silicone. The silicone contaminate on the lead prevents solderability and thus, weak solder joints will form, if they form at all.

Gideon Analytical Laboratories received a contaminated white translucent adhesive at the edge of a polyimide strip under a rubber keypad. Since most of the materials were organic, FTIR was the method of analysis first used to determine the foreign material.

The polyimide is a double-sided adhesive based flexible laminate (Kapton) film coated with adhesive on one or both and laminated to copper. There are two kinds of adhesive used in flex, epoxy, and acrylic. They each have positive and negative attributes that may make one or the other more suitable for a specific end use. The polyimide film enables the flex to bend many millions of cycles without failure. However, both acrylic and epoxy adhesives have inferior mechanical and electrical properties as compared to the Kapton core. In certain applications, the presence of an adhesive layer actually inhibits the use of flexible circuits. Therefore, a solution was needed to eliminate the adhesive layer from the substrate.

This filter is used in a water filter system for water consumption. The filters were plugging up rather fast with the pink material shown in the photograph below.

Since these problem types are unknown, one must choose the appropriate analysis method for material identification. Methods used are Fourier transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD) and Gas Chromatography-mass Spectrometry (GCMS)) since the filters were designed to filter out organics and inorganics. The FTIR, as well as GCMS, identified the organic portion as cellulose nitrate and the inorganic portion by XRD was identified as a yellow iron oxide hydrate.

This is a picture of a copper wire that used to have tin plating and nickel plated pad. The wire was running 120V at 60Hz. The connection was placed in a non-hermetical container where chlorides in the atmosphere were high. Over time the chlorides attacked the exposed copper and undermined the tin plating on the copper wires. The resistance in the wire increased, the copper arced due to this increased resistance and the socket assembly failure to corrosion.

This a micrograph of copper oxide deposits on nickel plating. The copper oxide is inhibiting the electrical conduction of a 120V light on terminals of a light bulb. This is an environmental failure stemming from the fact that the exposed copper on another part of this circuit, deposited copper oxide by arching, and this, in turn, caused an eventual loss in conduction to the bulb.

This arcing happens when low-level contaminants are present and concentrate over time. Once a copper oxide barrier forms, the resistance increases and arcing soon occurs on the deposited surface. This could end in either a fire or no conduction depending on environmental conditions existing at the time of the failure. This failure occurred in a museum which one would think had minimal contaminants. The analysis was performed on an SEM-EDS Gideon Analytical Laboratories has the capability and expertise to help clients from a variety of unrelated fields to understand the nature of environmental failures caused by excessive cleaning fluids, pressure washers, light exposure, accumulated chemical effects, and electrical conditions. We have been analyzing failures for over 30 years. We have EE, chemists, component, and analytical people to do the job right. Call us.

Gideon Analytical Laboratories received an industrial scale to analyze possible manufacturing defects and potential problems that affect “calibration” weight for long-term reliability. Many of these scales are used in heavy industry or veterinary applications. These scales also come in a variety of categories for different uses, including platform, drum, cylinder, and crane, among others.

There was some residual contamination that sat on top of the strain gauge but under the conformal coating, which can be seen in the picture at the top left. This appeared to be an electronic grade silicone coating. It had very poor adhesion to the substrate surface. Any moisture ingress (via humidity) would alter the resistivity on the strain gauge.

Gideon Analytical Laboratories performed analysis on several Melexis US2881 Sensors when the designer found shorts on the returned product from the field.

Melexis US2881 sensors are bipolar Hall-effect switches designed in mixed signal CMOS technology. They have a wide voltage operating range from 3.5V to 24V, have high magnetic sensitivity, and a chopper-stabilized amplifier stage, and are suitable for automotive or consumer applications.

Analysis revealed tin crystals (whiskers) spread throughout the top and bottom of the PCB, shorting out the MOSFET as well as the Hall sensor. Micrograph (left) and SEM-EDS analysis confirmed the presence of tin whiskers causing a short in both positive and negative leads. The tin whisker growth took place over several days to develop without voltage and with conditions known to promote growth.

Gideon Analytical Laboratories performed failure analysis on one opened splitter module LPF-200 PCB encapsulated in the black urethane potting material and housed in plastic. The PCB was burnt in one spot, and in that spot, a cavity existed under the carbonized epoxy of the PCB adjacent to the PTH. The trace line had a number of craters strongly suggesting an “electromigration” of copper. In order for electromigration to occur with copper a voltage, an acid and medium (moisture) must be present.

Gideon Analytical Laboratories performed failure analysis on good and bad Teapo electrolytic capacitors. A comparison leakage current test of the anode foil was set up. The leakage current over time is the best indicator as to whether the anode foil has an adequate crystal ratio of aluminum oxide forms to produce long-term reliability. The foil from the failed Teapo capacitors had multiple cracks like shown in the picture at the top left.

Gideon Analytical Laboratories received electrolytic capacitors for chloride analysis according to a prior analysis technique for determining the presence of chloride. The chloride analysis technique was developed because chlorine is a known catalytic corrosive element on aluminum.

The analysis was performed using an SEM-EDS system giving elemental analysis in relation to the intensity of the element at a specific wavelength or energy level (Kev). Since Kev (energy levels) for specific elements do not change, these are used to identify the elements in the sample. One of many SEM-EDS spectra pictures is at the top right. The analysis was performed on the tab, the lead, the fillet, the shank and the stitching where anode foil attaches.

Gideon Analytical Laboratories received three contaminated Buna-N diaphragms and several new ones for reference. These Buna-N diaphragms have a variety of applications, including in submersible level transmitters, actuary assemblies, air operated diaphragm pumps, and manual loading regulators. The goal was to identify the contamination and pinpoint its cause.

Upon examination under a stereo-zoom microscope, it was found that the surface of the sample contains a thick layer of a gel-like material. The gel had a brown tincture and fluoresced under black light. All three diaphragms were contaminated with this gel, which is pictured at the top left. The material from two patches of white material on the surface of the sample was removed and analyzed using FTIR. The white material can be seen pictured at the top right. The samples are similar to one another and showed absorptions due to fumed silica or amorphous silica with a small amount of the gel material seen in other samples.

Gideon Analytical Laboratories performed failure analysis on one Ansul IQ-396X, which was submitted for possible failure due to an electrical surge. These control units have two intelligent signaling line circuits (SLC), 396 intelligent device capacity (198 intelligent detectors and 198 monitors/control modules), four built-in output circuits, up to 64 internal output circuits/relays on optional modules in the unit, 99 programmable zone output relays, and manual sensitivity adjustment.

The CPU 400 unit was dissembled and the entire board and components were inspected under 40x to look for and evidence of EOS (electrical overstress) that may have affected the operation of the unit. No evidence was found. The power rails +5, +24, and ground were checked to ensure the lines were not shorted via a component failure. None were found. Continuity checks were made along the +5, +24 and the ground. No opens were found.

Gideon Analytical Laboratories performed failure analysis on a cold rolled steel plate that was received with what looked like tape prints, fingerprints, and black oil which all appear to interfere with the plating process.

Using one microliter of methylene chloride (ACS HPLC Grade) the surface of the cold rolled steel was collected in a glass vial. A portion was then evaporate onto a KCL wafer and analyzed on an FTIR to give spectra in the top picture. All the spectra compared showed aliphatic hydrocarbon oil in the 2900 cm-1 region with a small absorption of ester and acid component. The ester/acid material adheres to the steel surface and has been hydrated with an inorganic material (more than likely the iron in the steel).