E. Irissou, Industrial Materials Institute / -National Research Council Canada, Boucherville, QC, Canada; B. Arsenault, National Research Council Canada (CNRC-NRC), Boucherville,, QC, Canada
Aircraft structural components made of high strength aluminum alloys can be subjected to localized corrosion damage due to microscopic heterogeneities in the alloy such as secondary phases. The use of anodic claddings or coatings onto these structural aluminum alloy parts can overcome the problem by providing a cathodic protection. Thermal spray technologies are widely use for applying several type of coatings in the aerospace industry. Nevertheless, when temperature sensitive alloys are concerned such as the Al 7075 T651 alloy, thermal spraying of protective coatings is not straightforward. Indeed heat transfer from the coating process or defects at the coating-substrate interface such as porosities, micro-gap or grits can affect the mechanical properties integrity. Furthermore under cyclic load testing in salt water immersion, environmentally assisted cracking (EAC) and pitting corrosion at the coating-substrate interface can be observed. In this context cold spray anodic coating exhibiting high interface quality while being a very low temperature process as compare to other thermal spray techniques is investigated onto both Al 2195 and Al 7075 T651 alloy substrates for protection against EAC and localized corrosion. Interface quality before and after cyclic load testing in salt water immersion was investigated by SEM, micro-gap measurements and bond strength testing.
Summary: Aircraft structural components made of high strength aluminum alloys can be subjected to localized corrosion damage due to microscopic heterogeneities in the alloy such as secondary phases. The use of anodic claddings or coatings onto these structural aluminum alloy parts can overcome the problem by providing a cathodic protection. Thermal spray technologies are widely use for applying several type of coatings in the aerospace industry. Nevertheless, when temperature sensitive alloys are concerned such as the Al 7075 T651 alloy, thermal spraying of protective coatings is not straightforward. Indeed heat transfer from the coating process or defects at the coating-substrate interface such as porosities, micro-gap or grits can affect the mechanical properties integrity. Furthermore under cyclic load testing in salt water immersion, environmentally assisted cracking (EAC) and pitting corrosion at the coating-substrate interface can be observed.
In this context cold spray anodic coating exhibiting high interface quality while being a very low temperature process as compare to other thermal spray techniques is investigated onto both Al 2195 and Al 7075 T651 alloy substrates for protection against EAC and localized corrosion. Interface quality before and after cyclic load testing in salt water immersion was investigated by SEM, micro-gap measurements and bond strength testing.
