Stainless steels' passivity is primarily due to the ability of its chromium content to build up an oxide film. The oxide film provides protection from corrosion and chemical attack. This film is normally destroyed or damaged during the manufacturing process. It is common practice to restore the damaged oxide film layer by a passivation treatment.
BLACK PASSIVATION (BLACK PASSIVATE) is better known as "Black Oxide Class 2, Black Oxide Class 3, or Black Oxide Class 4" for corrosion resistant steel alloys. It is a conversion coating that produces a uniform, attractive, and non-reflective black finish on stainless steels. It provides a permanent black color with exceptional strength and elasticity. The finish does not chip, peel, craze, or rub off and provides good resistance to wear and abrasion. The coating reduces friction of moving parts, preventing galling and scoring. Improved corrosion resistance is obtained and there is a negligible .00001 - .00003 dimensional change.AMS-2700, Method 1, Type 1 Low temperature nitric acid with sodium dichromate AMS-2700, Method 1, Type 2 Medium temperature nitric acid with sodium dichromate AMS-2700, Method 1, Type 3 High temperature nitric acid with sodium dichromate AMS-2700, Method 1, Type 4 40% nitric acid for free machining steels AMS-2700, Method 1, Type 6 Low temperature nitric acid AMS-2700, Method 1, Type 7 Medium temperature nitric acid AMS-2700, Method 1, Type 8 High temperature, high nitric acid concentration SP-112 Treating stainless steel parts to prevent corrosion MIL-DTL-14072 Finish No. E-300 Passivate per ASTM A380 ASTM A967 Nitric 1 Chemical Passivation Treatment - medium temperature with sodium dichromate ASTM A967 Nitric 2 Chemical Passivation Treatment - low temperature nitric acid ASTM A967 Nitric 3 Chemical Passivation Treatment - medium temperature nitric acid ASTM A967 Nitric 4 Chemical Passivation Treatment - high temperature, high nitric acid concentration AMS-QQ-P-35, Type II Passivation Treatment - medium temperature with sodium dichromate AMS-QQ-P-35, Type VI Passivation Treatment - low temperature nitric acid AMS-QQ-P-35, Type VII Passivation Treatment - medium temperature nitric acid AMS-QQ-P-35, Type VIII Passivation Treatment - high temperature, high nitric acid concentration QQ-P-35, Type II Passivation Treatment - medium temperature with sodium dichromate QQ-P-35, Type VI Passivation Treatment - low temperature nitric acid QQ-P-35, Type VII Passivation Treatment - medium temperature nitric acid QQ-P-35, Type VIII Passivation Treatment - high temperature, high nitric acid concentration ASTM A380 Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems MIL-S-5002 Surface Treatments And Inorganic Coatings For Metal Surfaces Of Weapons Systems MIL-STD-171E Finish No. 5.4.1 Clean and passivate, QQ-P-35 (Clean ASTM A380)
Additionally, our passivation processes meet or exceed the custom specifications of most major U.S. companies. If you have a question about a particular passivating specification or have a custom specification, please call us and ask.
CAPABILITIES: Our facilities and highly skilled technicians are able to meet your passivating needs today. We can accommodate most any job size from small to large. Acton Metal Processing Corp. is your source for cost-effective clear passivating or black passivating.