Surface Modification of Engineering Materials by Physical Vapour Deposition Coatings and Ion Implantation

Abstract

In this study, Magnetron Sputtering Ion Plating (MSlP) was used to apply layers of TiAlN, TiAlCN, TiAlOC and TiAlOCN at different deposition pressures, namely (Io-2 mbar), (5 x 10•3 mbar) and (35 x 10'4 mbar). The percentage of reactive gases was rangmg from 5 % to 35%, these reactive gases are nitrogen acetylene and carbon

dioxide or mixture of these gases. The effect of these percentages on mechanical properties of the deposited layers is considered. In this study the following gases were used to form different layers, nitrogen to form TiAlN layers, a mixture of acetylene and nitrogen to form TiAlCN layers.Also, carbon dioxide gas was used with TiAl as target to form TiAlOC layers and mixture of carbon dioxide and nitrogen to form TiAlOCN layers. The deposition parameters as deposition pressure, the percentage of reactive gases, affect greatly the chemical composition of deposited layer and its mechanical properties. Many tests were preformed to investigate the mechanical properties of deposited layers such as scratch test, adhesion and cohesion strength test and hardness test, also the formed phases were investigated by X-ray diffraction and morphology of the layers was examined by Scanning Electron Microscopy. The result of tests showed that, the hardness of deposited TiAlN layer increase at low deposition pressure. The best result was at pressure process 5 x I o-3 mbar, the hardness was 42 GPa. The adhesion strength was also maximum at pressure 35 x 10'4 mbar and 5 x 10•3 mbar, it was 90N.

The impact strength of deposited layers increased by decreasing deposition pressure and best results were at pressures of 35 x 10"4 mbar and 5 x 10•3 mbar, it was one million impacts with 500 N loads. Friction coefficient and gram s1ze of deposited layers decreased by decreasing deposition pressure.