Abstract
Contamination out gassing is the release of volatile compounds from a solid or liquid, often with the addition of heat. These compounds may condense as thin films on surfaces and cause oxidation, corrosion or contact resistance. Out gassing is more likely to be problematic in system environments in which the temperature is elevated and available oxygen is limited. Moisture in the environment may also be a contributing factor. The paper includes an investigation of three case studies of different types of contamination out gassing that led to system failures. The analytical tools and methods used to determine root cause will be discussed in each case. The first case study examines bridging conductive copper dendrites on a system cable used in a PC system related to the cable shipping materials. The second failure to be discussed is the corrosion of Ag conductor traces in a display panel due to out gassing of sulfur compounds from nearby foam cushioning pads. The third case will explore a DC motor failure due to siloxane out gassing from an adjacent foam pad. Prevention of out gassing can be controlled by material selection and supply chain management. There are also standard test methods that can be used to detect out gassing in suspect material. These methods can be used in conjunction with the specification as requirements for qualification of new materials. Two ASTM test methods, ASTM E-595-77/84 and ASTM E1559-03 pertain to contamination out gassing. This paper includes a discussion of both methods and their advantages and disadvantages as part of a test plan.
