MIL-STD-1250 Corrosion Prevention And Deterioration Control In Electronic Components And Assemblies S/S By Mil-Hdbk-1250This standard establishes minimum requirements for procedures, materials and systems for protecting electronic components in DoD systems and assemblies from adverse environments. Protective measures shall be sufficient to maintain performance characteristics within specified limits both during and after exposure to moisture, high and low temperatures, corrosive gases, chemicals and microbial fungal attack.

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MIL-STD-1250A

5.12 Temperature resistance. Materials shall be selected which maintain their desired properties throughout the temperature range anticipated to be experienced by the equipment. Attention is directed to the possible adverse effects of cycling temperatures or pressures, with consequent condensation of water vapor, expansion and contraction of parts, creeping of lubricants and breathing of seals.

5.13 Compatibility with other materials. Care shall be taken to select materials which are compatible with other materials in the equipment. Special attention shall be given to corrosion prevention and control, avoidance of outgassing and the effect of coatings on electrical properties. Certain combinations of materials shall be avoided; examples are listed in table IX.

5.13.1 Outgassing. Materials, as installed in the equipment, shall not liberate corrosive or reactive fumes under any conditions encountered during storage, shipment or service. Special consideration shall be given to materials, such as insulation on wire, which may be exposed to overheating and resultant outgassing or breakdown. Extra attention shall also be paid to combinations of materials in closed compartments, where even a small amount of outgassing may reach dangerous concentration in time. Damage from outgassing shall be minimized by the following techniques:

a. Organic materials shall be thoroughly cured before assembly, especially acid- activated plastics

b. Polyvinylchloride shall not be used

c. Where practical, the use of neoprene, phenolic, and polysulfide shall be avoided in closed areas

d. Cadmium shall not be used in closed compartments

e. Acid emitting, liquid or vapor, room temperature vulcanizing (RTV) silicones shall not be used.