Salt fog corrosion resistance of HVOF WC-10Co-4Cr coated and electrolytic hard chrome plated AerMet 100 and 300M steel alloys

摘要

1. Bare AerMet 100 provides better corrosion resistance than bare 300M due to high chromium and nickels contents. 2. Both WC-10Co-4Cr and EHC improves corrosion resistance over AerMet 100 and 300M bare substrates. 3. The 254μm thick coating provides more corrosion protection than the 76μm thick coating for both the WC-10Co-4Cr and EHC. 4. Long term salt fog tests show that WC-10Co-4Cr has a better corrosion resistance than EHC. The performance was reversed in short-term electrochemical corrosion tests. 5. Surface connected cracks that form during coating application of EHC appears to provide paths for corrosion attack in the substrate. 6. The exact mode of corrosion attack in HVOF is not clear, additional work is required to determine if there are networks of fine cracks in the coating that allow corrosive media to reach the substrate.