Passivate Services A process designed to remove foreign metals from the surface of stainless and corrosion resistant steels and to promote natural tendency of surface to oxidize. Does not change the appearance of the base metal. Process purifies surface and therefore improves corrosion resistance.
Spec.	Thickness	Comment
AMS-P-35	No dimensional change
Type II		Medium temperature with sodium dichrominate.
Type VI		Low temperature
Type VII		Medium temperature
Type VIII		Medium temperature with high concentration of nitric acid.
		24 hour humidity test required. Salt spray test may be required, if specified, in addition to humidity test.
Spec.		Thickness	Comments
ASTM-A-967-99el**			**Alternate spec to supercede QQ-P-35. In addition to passivate using Nitric acid (and Sodium Dichromate), this ASTM also introduces passivation using Citric acid.
			Nitric Acid (Vol. %)	Sodium Dichromate (Weight %)
Nitric 1		120°-130°F 20 min.	20-25	2.5 + 0.5
Nitric 2		70°-90°F 50 min.	20-45	none
Nitric 3		120°-140°F 20 min.	20-25	none
Nitric 4		120°-130°F 30 min.	45-55	none
Nitric 5		As required	As required to pass tests
Practice A		All tests need not be performed unless specified.	Water Immersion Test
Practice B			High Humidity Test
Practice C			Salt Spray Test
Practice D			Copper Sulfate Test
Practice E			Potassium Ferricyanide - Nitric Test