What It is
How it’s done
509 N Wolf Rd Wheeling, IL 60090
Phone: 847-215-8880 Fax: 847-215 7066
Passivation is the removal of free iron from the surface stainless steel. The acid treatment dissolves the free iron and facilitates the formation of a thin, transparent corrosion resistant oxide layer
Passivation is done by immersing the part in a solution of nitric acid, nitric acid and sodium dichromate or citric acid at a controlled temperature
Nitric Acid
20-40% by volume
70º-140º F
20-40 min
All Ni/Cr and high Cr except 330 and 440
Nitric Acid / Sodium DiChromate
HNO3 (20% by Volume) + Na2 Cr2 O7 (2-6 oz/gal by weight)
120º - 140º F
20 - 40 min
Straight Chromium grades
High carbon / High Chrome (440 series)
Precipitation Hardened (17-7PH, A-286)
All Ni/Cr and high Cr
50% Nitric Acid
HNO3 (50% by volume)
120º - 140º F
20 - 40 min
Straight Chromium grades
High carbon / High Chrome (440 series)
Precipitation Hardened (17-7PH, A-286)
All Ni/Cr and high Cr
Citric Acid
Acts as chelator
5 oz/gal citric
120 - 160º F
5-20 minutes
Environmentally friendly
Precipitation Inhibitor
Passivation