The solder joint reliability of ceramic chip resistors assembled to laminate substrates has been a long time concern for systems exposed to harsh environments. In this work, the thermal cycling reliability of several 2512 chip resistor lead‐free solder joint configurations has been investigated. In an initial study, a comparison has been made between the solder joint reliabilities obtained with components fabricated with both tin‐lead and pure tin solder terminations. In the main portion of the reliability testing, two temperature ranges (−40‐125°C and −40‐150°C) and five different solder alloys have been examined. The investigated solders include the normal eutectic Sn‐Ag‐Cu (SAC) alloy recommended by earlier studies (95.5Sn‐3.8Ag‐0.7Cu), and three variations of the lead‐free ternary SAC alloy that include small quaternary additions of bismuth and indium to enhance fatigue resistance.

A response to the chemical or biological contamination of aircraft requires the use of a suitable decontaminant. Among possible chemical decontaminants, vapour phase hydrogen peroxide appears to be a likely candidate in terms of a combination of efficacy, low environmental impact and potential for materials compatibility. The present paper examines the effect of hydrogen peroxide, both in the vapour phase and as a liquid concentrate on two common structural materials used in aviation, namely 2024 and 7075 age hardenable aluminium alloys and on 304 austenitic stainless steel, the latter as employed in galley and lavatory surfaces. The present paper characterises both the effects of hydrogen peroxide on the microstructure of the materials and the impact that decontamination has on the tensile properties and corrosion resistance of these materials. Microstructural effects are both relatively small in magnitude and confined to a region immediately beside the exposed surface. No systematic effect is found on either the tensile properties or the post-exposure corrosion resistance of the three alloys examined. These observations are encouraging in terms of the use of vapour phase hydrogen peroxide for decontamination applications.

The solder joint reliability of ceramic chip resistors assembled to laminate substrates has been a long time concern for systems exposed to hush environments such as those found in automotive and aerospace applications. This is due to a combination of the extreme t e m p e r a m excursions experienced by the assemblies along with the large coefficient of thermal expansion mismatches between the alumina bodies of the chip resistors and the glass-epoxy composites of the printed circuit boards (PCBs). These reliability challenges are exacerbated for components with larger physical size (distance to neutral point) such as the 2512 resistors used in situations where higher voltages and/or currents lead to power dissipations up to 1 Wan. In this work the thermal cycling reliability of several 2512 chip resistor lead free solder joint configurations has been investigated. In an initial study, a comparison has been made between the solder joint reliabilities obtained with components fabricated with both tin-lead and pure tin solder terminations. In the main portion of the reliability testing, two temperature ranges (-40 to 125 "C and -40 to 150 "C) and five different solder alloys have been examined. The investigated solders include the normal eutectic SnAgCu (SAC) alloy recommended by earlier studies (95.5Sn-3.8Ag-O.7Cu), and three variations of the lead free ternary SAC alloy that include small quaternary additions of bismuth and indium to enhance fatigue resistance. For each configuration, thermal cycling failure data has been gathered and analysed using two-parameter Weibull models to rank the relative material performances. The obtained lead free results have been compared lo data for standard 63Sn-37Pb joints. In addition, a second set of thermally cycled samples was used for microscopy studies to examine crack propagation, changes in the microstructure of the solders, and intermetallic growth at the solder to PCB pad interfaces.

Decontamination of airliner cabins may be required, for example, in the event of an epidemic or pandemic. To be performed safely, decontamination must be compatible with aircraft materials and systems. This paper examines the suitability, with respect to cabin textiles, of vapour phase hydrogen peroxide for airliner decontamination applications. The effect of vapour phase and liquid hydrogen peroxide on common airliner interior textile materials, namely wool, nylon, polyester, and Nomex, has been studied by examining the physical and chemical changes and the resulting effect on mechanical properties caused by decontamination. The physical changes induced by the sorption of moisture had an effect on the mechanical properties of all of the materials examined. However, only wool attacked chemically by hydrogen peroxide experience a significant effect on its mechanical properties.