MIL-STD-1568 Materials And Processes For Corrosion Prevention And Control In Aerospace Weapons SystemsThis standard establishes the requirements for materials, processes and techniques, and identifies the tasks required to implement an effective corrosion prevention and control program during the conceptual, validation, development and production phases of aerospace weapons systems. The intent is to minimize life cycle cost due to corrosion and to obtain improved reliability.

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MIL-STD-1568C

5.7.6  Interference fit fasteners.  Cadmium plated interference fit fasteners shall not be used in contact with titanium.  Fastener holes for interference fit fasteners shall be primed with MIL-PRF-23377, Type I, Class 1 or 2 or MIL-PRF-85582, Type I, Class 2 and shall be completely dry prior to assembly.

5.8  Special considerations.

5.8.1  Cadmium plated parts.  Cadmium plated parts such as press fit bushings shall not be used in contact with titanium components.  Cadmium and silver plated parts and fasteners shall not be used in contact with titanium in applications where temperatures exceed 450 °F (232 °C).  Titanium fasteners or components shall not be cadmium plated.

5.8.2  Engine corrosion susceptibility testing.  Selected materials and coatings shall be corrosion tested under simulated engine environmental conditions appropriate to their final usage during operation, handling, and storage of the engine.  A new or newly overhauled engine shall

be selected for the corrosion susceptibility test.  Prior to starting the test, the engine shall be disassembled and an inspection conducted to determine the condition of all parts normally exposed to atmospheric conditions.  Detailed photographic coverage of these parts shall be used for comparison with post test conditions.  The engine shall then be reassembled, pretest performance calibrated, and subject to 25 AMT cycles while being injected with a two percent of airflow weight spray solution, consisting of the following materials dissolved with distilled water to make one liter of salt spray solution.

Chemical designation                                                             Quantity per liter of spray solution

NaC1 (c.p.)                                                                                         23 grams Na2S0410H20                                                                                      8 grams Stock solution                                                                                     20 milliliters

The stock solution shall be composed of the following materials dissolved with distilled water to make one liter of stock solution:

Chemical designation                                                             Quantity per liter of stock solution

KC1 (c.p.)                                                                                             10 grams KBr                                                                                                       45 grams MgC12  6H20 (c.p.)                                                                             550 grams CaCl2  6H20 (c.p.)                                                                               110 grams

At specified intervals during the test, the engine shall be subjected to internal inspections to detect any evidence of corrosion or progression of corrosion of internal parts.  Upon completion of the test, a performance check shall be conducted and the engine disassembled and inspected for evidence of corrosion.  Detailed photographs shall be taken of all parts that show evidence of corrosion.  Test specimen evidence of metallurgical analyses that completely characterizes the types of corrosion found shall be presented.  The test results shall be considered satisfactory

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