EFFECT OF PARTICLE SIZE AND BONDING LAYER ON PLASMA SPRAYED Al2O3-13%TiO2 COATINGS

To date, plasma sprayed alumina titania have been widely used as wear resistance coatings in textile, machinery and printing industries. Previous studies showed that the coating microstructures and properties were strongly depended on various parameters such as ceramic composition, grain size powders and spray parameters, thus, affecting the melting degree of the alumina titania during the deposition process. This paper discusses the effect of Al2O3-13% TiO2 particle size powders and the presence of Ni-Al as a bonding layer on commercial marine grade mild steels using a plasma spray technique. The optimum plasma spray parameters were identified for both nanoparticle and microparticle powders in order the get the best coating properties in term of microhardness, surface roughness, coating porosity and specific wear rate. It was found that microparticle powders exhibited better surface roughness than the nanoparticle powders. On the other hand, the nanoparticle powder coating gave an excellent microhardness, with less coating porosity and better wears resistance than those of microparticle powders, which was likely due to the microstructure that consisted of bi-modal structures, resulting greater strengthening effect on both fully and partially melted regions. By sacrificing the surface smoothness, the presence of Ni-Al bonding layer on the other hand, was able to generate a good quality coating with less porosity percentage.