Our primary MnPhos military customers most often require coatings adhering to Heavy Manganese Phosphate Coating specification MIL-DTL-16232 type M, class 1, 2 or 3. This specification is also referenced by MIL-STD-171 finish numbers 184.108.40.206, 220.127.116.11 and 18.104.22.168. Special provisions including exceptions to standard coating weight, stress bake and hydrogen embrittlement relief as per drawing A7309999 may also be specified. General Small Caliber Weapon Systems Quality Assurance per 12993884 is often incorporated by contract or drawing designation.
- View or print military specification: MIL-DTL-16232G.
- View or print military standard: MIL-STD-171. Finish numbers 22.214.171.124, 126.96.36.199, 188.8.131.52
- View or print military drawing: A7309999.
- View or print military drawing: 12993884.
- View or print our no-charge: 3-PAGE PHOS OUTLINE suitable for submission to your PCO for most contracts.
Rarely, the blast pre-treatment procedure specified by MIL-DTL-16232 is replaced with a multi-stage chemical pre- treatment and grain refinement procedure. It is imperative to control the manufacturing process in order to provide a surface free of contamination such as rust, mill scale and heat-treat scale. A wide rage of impregnated contamination must also be avoided.
Although we coat hundreds of thousands of Metal Injection Molded (MIM) and powdered metal (PM) parts, these substrates (regardless of the alloy) might not be suitable for high-quality MnPhos coatings, depending on the casting methodology and manufacturing techniques.
Some castings may require blasting before precision machining to remove fused zirconium and other glass-like compounds that unintentionally remain bonded to surface of the casting. This blasting procedure must take place before any precision machining operations.