Enhancing corrosion resistance of helicopter skid shoes by HVOF method

Havaniroz helicopters fly in all parts of dear Iran and performing missions in different weather conditions has a great impact on the parts of these types of helicopters and sometimes they cause corrosion. In this research, to reduce the amount of wear and adhesion and enhancing corrosion resistance of helicopter skid shoes, the HVOF process is used. The HVOF process is one of the most advanced spraying systems which the most important advantages of that are the very effective and uniform heating of particles due to the intense turbulence that occurs in the combustion chamber, as well as very little surface oxidation. In this article, to reduce the wear and adhesion of helicopter brake shoes, tungsten carbide coating was done on 7075 aluminum. Coating was done by thermal spraying and with the help of tungsten carbide powder, in addition to increasing the hardness and resistance of the surface, the amount of wear was reduced to a significant extent. The metallographic structure of the part after the WC86%-Co10%-Cr4% coating had high density, no oxide particles and not melted. By creating this coating, the amount of adhesion increased to 89 MPa, which is not comparable to conventional coatings. Also, the results of the hardness tests show that the microhardness measurement of the coating had a hardness of about 1300 Vickers, which indicates that this hardness is higher than other coatings in the form of plating. By using WC86%-Co10%-Cr4% coating, the amount of wear during helicopter landing at 1000 meters reached , which shows the high hardness and high quality of the coating..