الفهرس | Only 14 pages are availabe for public view |
Abstract This research is concerned with studying the effect of the electroless plating on mechanical, microstructure and corrosion properties of heat-treated electroless Ni-P , Ni-Co-P and Ni-W-P alloys . Experiments were carried out in a glass vessel placed in a constant temperature water bath . The volume of plating solution to low Carbon Steel test specimen surface area (V / S ) was 15Cm3 / Cm2 in all cases . The variables embodied are : plating time and heat treatment temperatures. The effect of changing plating time on the coating thikness for the three Ni-P , Ni-Co-P and Ni-W-P are studied. The effect of heat-treatment on the Crystallization behavior of an electroless Ni-Co-P and Ni-W-P is also studied . For as plated samples the X-ray diffraction pattern of Ni-Co-P deposits showed microcrystalline deposit of P , Co, Ni , Ni5P2 , Ni7P3 & Ni3P . Well Crystalline of free Co & Ni and very crystalline and grain growth of Ni7P3 have been noticed for deposit heat-treated at 400 C for one hour , around this heat-treatment temperature the maximum hardness was achieved. Heat-treatment for one hour at different temperature of electroless Ni-P , Ni-Co-P and Ni-W-P coatings showed excellent corrosion resistance of Ni-Co-P coating compared to Ni-P and Ni-W-P deposits. The obtained results show minimum surface wear occurred at 700 C . ……………………………………………………………………………………….. |