دراسة الخواص الميكانيكية و الفيزياوية للكاربون الحراري المترسب بطريقة (CVD)

This research is concerned with a detailed study to determine the effecting of a number of variables on a deposited pyrolytic carbon coating by thermal decomposition of hydrocarbon gas ( liquid benzene ) at temperatures range (1500°C-1900°C) . That is firstly: from the determination of the deposition parameters (Temperature-T , Pressure-P and time-t) and secondly: study the physical and mechanical properties of the carbon coated especially on graphite substrate due to its high temperature resistance. An investigation has been carried out to study the effect of substrate temperature (T) and hydrocarbon gas pressure (P) on the deposition process of coated layer formation, its microstructure features and other properties such as apparent porosity, real density, roughness, hardness and adhesion with the substrate . The conclusion of the present work is first, increasing the substrate temperature and hydrocarbon gas pressure; resulting in a relative increasing of deposition rate (i.e. increase in thickness of coating). Second, increasing in substrate temperature (at constant P and t); resulting in decreasing the apparent porosity and increasing in density, hardness and adhesion. Third, increasing in hydrocarbon gas pressure (at constant T and t); resulting in a decreasing in density, hardness, porosity and increase in porosity. This work shows also results of a microstructures and X-Ray Diffraction which confirm the formation of the pyrolytic carbon coated.