The effect of the material and distance of the substrate on the characteristics of the alumina nanopowder coating with plasma spray method

In this paper, the effect of the material and distance of the substrate on the characteristics of gamma alumina nanopowder coated by plasma spray method are investigated. For this purpose alumina nanopowder were coated on the two types of stainless steel and Pyrex glass substrates using a plasma torch. Morphological characteristics of the prepared nanolayer are studied by investigating the scanning electron microscope patterns. Also, the structure and phase changes of deposited alumina are investigated by X-ray diffraction spectrum. The results of this study show that the amount of particles deposition on the steel substrate is more than the glass case. Also, it is shown that by increasing the substrate distance, the amount of particle deposition is decreased for substrates. There is one optimum distance for substrate position with respect to the nozzle exit of the torch for produce and suitable coating and its control. One important result of this experimental study is the phase transfer of alumina from gamma to alpha due to the high temperature of the plasma torch