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

by the procuring activity. Resistance to fungus shall be established in accordance with ASTM G 21, ASTM D 4300, or by MIL-STD-810. Fungal growth shall be further discouraged by removal of dust, dirt, fingerprints and other contaminants from the surface before assembly, and by maintenance of low humidity.

5.11.1 Metals. Although not nutrients for fungus, metals are attacked by acid liberated by microbial growth. Care shall be taken to avoid use of protective finishes which support fungi, to keep parts clean and to keep humidity low.

5.11.2 Glass and ceramics. While glass and ceramics are not in themselves funginutrient, the coatings used on optics often support fungal growth. To prevent or minimize microbial attack, glass, ceramics and optics should be smooth and clean, with an unbroken surface and glazed. Where practicable, fungicide should be incorporated into the coating for optics.

TABLE VIII. Funginert materials.

Funginert in all grades and conditions

Some grades funginert; establish by testing in accordance with

ASTM G 21 or MIL-STD-810

Asbestos

Ceramics

Chlorinated polyether

Glass Metals Mica

Silicone glass fiber Phenolic nylon fiber Diallylphthalate Polyacrylonitrile Polyamide Polycarbonate

Polyetheylene (High Density) Polymonochlorotrifluoroethylene Polypropylene

Polystyrene Polytetrafluoroethylene Polyethylene terephthalate Silicone resin

Acetal resins

Acrylonitrile-vinylchloride copolymer

(variable)

Cellulose acetate (variable) Cellulose acetate butyrate Epoxy glass fiber laminates Epoxy resin

Melamine-formaldehyde Natural rubbers (susceptible) Phenol-formaldehyde Polymethyl methacrylate Polyvinylchloride

Polyvinylchloride acetate (susceptible) Polyvinylfluoride

Polyvinylidene chloride (variable) Plastic laminates using:

Cotton filler (susceptible) Linen filler (susceptible) Paper filler (susceptible)

Wood-flour filler (susceptible) Synthetic rubbers

Urea-formaldehyde