Abstract
The adhesion of a thermal spray coating to the substrate is mainly due to the anchor effect. Therefore, surface roughening by blasting is essential as a pretreatment for thermal spraying. In this paper, the relationship between surface roughness (Ra, RΔq) and adhesion strength, and the effect of residual blasted material on adhesion strength of ceramic coating obtained by the authors is reviewed. Two substrates were used: SUS304 (a stainless steel) and A5052 (an Al-Mg aluminum alloy) . Three types of brown alumina blasting materials with different grain sizes were used. Surface roughness with various blast pressure and blast angle is firstly shown. YSZ powder was plasma sprayed onto the blasted substrate under the different blasting conditions, and the tensile adhesion strength is secondly shown. The relationship between surface roughness and tensile adhesion strength showed a positive correlation on SUS304 substrate, but a negative correlation on A5052 substrate. It was confirmed that the blasting conditions should be selected appropriately depending on the substrate material. It was also concluded that residual blasted material does not decrease the tensile adhesion strength.
