Inventors:
Owen M. Briles - Rockford IL, US
Mark Jaworowski - Glastonbury CT, US
Michael A. Kryzman - West Hartford CT, US
Assignee:
United Technologies Corporation - Hartford CT
Hamilton Sundstrand Corporation - Windsor Locks CT
International Classification:
C23C022/07
US Classification:
148253, 148261, 148275, 106 1412, 25238954
Abstract:
The present invention relates to a process for forming a chromate-free, corrosion resistant coating on a product formed from magnesium or a magnesium alloy and to a solution used for forming the coating. The solution has phosphate and fluoride ions and contains from 1. 0 g/l to 5. 0 g/l of an active corrosion inhibitor selected from the group consisting potassium permanganate, sodium tungstate, sodium vanadate, and mixtures thereof. The solution may also containing from 0. 1 to 1. 0 vol % of a surfactant which reduces reaction time. The solution is maintained at a temperature of 120 to 200 degrees Fahrenheit and has a pH of 5 to 7. The process for forming the coating broadly comprises degreasing the magnesium or magnesium alloy product in a degreasing solution, cleaning the product in a highly alkaline cleaning solution, deoxidizing the product in a deoxidizing solution, and immersing the product in the coating solution for a time period of 15 minutes to 90 minutes.