Selecting encapsulants and potting compounds for electronic modules

Experience has demonstrated that in spite of the most careful analyses of material properties and expected environmental conditions, failures of electronic hardware attributed to potting compounds and encapsulants have occurred in service. Examples of critical failures include cracking of soldered joints and components, excessive changes in electrical characteristics of components and assemblies, chemical reactions between potting and encapsulating materials and other materials of the assembly, and polymer reversion under conditions of high humidity and temperature.