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

3.    DEFINITIONS

3.1  Standard definitions.  Standard definitions relating to corrosion and corrosion testing are found in ASTM G 15.  The definitions that follow supplement or expand those found in ASTM G 15.

3.2  Corrosion.  A specific type of deterioration resulting in damage or impairment of metals or metallic parts as the result of attack by moisture, air, acid, alkali, chemicals, or electrochemical action.  Although mechanical stress is a factor in certain types of corrosion, damage or breakage as the result of purely mechanical load or shock is not included in this document.

3.3  Corrosion-resistant steels.  Steel with sufficient alloy content (usually chromium and nickel) to resist atmospheric corrosion; sometimes called "stainless" steels, although they are neither stainless nor rustless.  A wide variety of analyses and properties are included in the term "corrosion-resistant steels."

3.4  Deterioration.  A general term describing the impairment of desired physical, chemical, mechanical or electrical properties resulting from aging, environmental exposure, chemical or biological attack, or changes in temperature or pressure.

3.5  Dissimilar metals.  Any combination of bare metals which is not indicated as a permissible couple in table III, Galvanic Couples.  The greater the difference in the electromotive force (EMF) the more dissimilar are the two metals and the greater is the galvanic attack on the anodic metal (see 3.9).

3.6  Electromagnetic interference (EMI).  Any spurious external disturbance causing unwanted response in electronic equipment, or any unwanted signal emanating from the equipment; sometimes called radio frequency interference (RFI).

3.7  Encapsulation.  The embedment and complete envelopment of an item or assembly in a solid mass of a plastic, elastomeric, or ceramic insulating material.

3.8  Fungi.  Any of a large group of thallophytic organisms described as molds, mildews, mushrooms, yeasts, or any organism absorbing nutrition from living or dead organic materials.

3.8.1  Fungicidal.  Capable of killing fungi.

3.8.2  Funginert.  Neither destroying nor supporting the growth of fungi.

3.8.3  Funginutrient.  Providing sustenance for fungi.

3.8.4  Fungus resistant.  Unaffected by fungi, as established through testing in accordance with MIL-STD-810.

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