No abstract

No abstract

The vulnerability of hearing aid devices to corrosion is critical due to their exposure to various kinds of ionic contaminants from the human body, such as sweat, sebum, and so forth, and harsh climatic conditions such as high temperature, humidity, and atmospheric pollutants. The device failure rate will vary depending upon the type of geographical location at which the device is used and root cause failure analysis is a crucial tool to understand the effect of geographical location on corrosion failures. In this study, field failed hearing aid devices from Europe, the United States, and Japan markets were investigated using a scanning electron microscope and elemental dispersive spectroscopy to locate failure mechanisms and causes. Information from the analysis was used for statistical analysis to compare the performance of the devices in the three markets based on failure percentage and failure probability for different parts and components. Solder terminals, battery contacts, light‐emitting diodes, and wireless‐link coil showed consistent and high failure probability across all three markets, whereas a higher failure rate for microphones was found in Europe and the United States market as compared to the Japanese market. The majority of the components corrosion failures occurred in the presence of high chloride ions from human sweat and the atmospheric conditions, whereas potassium hydroxide from the leakage of Zn–air battery was found as the additional cause for microphone failure.

The Zinc-air primary batteries (ZAB’s) are prone to electrolyte leakage upon exposure to high temperature and humidity conditions. Potassium hydroxide is a hygroscopic and corrosive compound and it can cause various electrochemical corrosion failures for the attached electronics inside a device. In this study, the effect of temperature and humid conditions on the leakage of Potassium hydroxide electrolyte from three different Zinc Air Battery variants were investigated. The batteries were exposed to hot and humid conditions, and a qualitative Gel test with pH indicator was used to visually observe the leakage from the individual set of battery variants. The residues of the released electrolyte was identified by FTIR and quantified using a titration method. SEM-EDS analysis was also performed to examine the surface of the batteries and sealants for eventual damage. The related effect of electrolyte leakage on the reliability of the batteries was performed by a voltage discharge test. The hygroscopicity properties of pure Potassium hydroxide were studied using a water sorption/desorption equipment and was correlated with electro impedance spectroscopy analysis using an interdigitated test board. The results from the study indicate that the increase in temperature caused an increased amount of electrolyte leakage under saturated humid conditions. Leakage of Potassium hydroxide electrolyte caused damage to the sealant gasket, clogged the oxygen ventilation holes of the batteries, and exhibits high hygroscopic properties when exposed to high temperature and humid conditions.

This study examined the composition and characteristics of scales formed at different depths in an oil production well, which had developed over years of well operation, workovers, and interventions, by the combined use of optical microscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, transmission electron microscopy, and X‐ray diffraction. The iron‐rich scales consist of several mineral phases, including a dominant portion of akagneite and hibbingite, some barite, silicon dioxide, copper sulfide, and small amounts of iron oxide and calcium carbonate. The scales typically have a layered structure consisting of five to six distinct layers, which impacts steel corrosion processes. The type of corrosion beneath the scale surface was found to be diversified. Pitting morphology corresponding to different stages in the development of scales was observed. The relation between pitting density and the extent of corrosion was analyzed. The effects of environmental factors, including calcium, chlorine, oxygen content, steel microstructure, and multiphase flow, on scale formation and corrosion mechanisms, were discussed. The results provide important insights into the formation of scales and the under‐deposit corrosion processes in the oil production tubes.