Kelimu Tulugan

Characteristics of deposited boron doping diamond on tungsten carbide insert by MPECVD

Diamond-coated cutting tools are used primarily for machining non-ferrous materials such as aluminum–silicon alloys, copper alloys, fiber-reinforced polymers, green ceramics and graphite. Because the tool life of cemented carbide cutting tool is greatly improved by diamond coating, and typically more than 10 times of the tool life is obtained. However, research of boron-doped diamond (BDD) coating tool has not been fully researched yet. In this study, we have succeeded to make boron-doped microcrystalline and nanocrystalline diamond-coated Co-cemented tungsten carbide (WC–Co) inserts. Microcrystalline BDD thin film is deposited on WC–Co insert by using microwave plasma enhanced chemical vapor deposition (MPECVD) method. Scanning electron microscope (SEM) and Raman spectroscopy are used to characterize the as-deposited diamond films.1,2

The preparation and electrochemical performances of Al-Si/C nanocomposite anode for lithium ion battery

The microstructure and electrochemical performance of Al-Si, Al-Si/C nanocomposite were investigated as the anode for lithium ion battery. The Al-Si nanoparticles were prepared by the arc-discharge method. The Al-Si/C nanoparticles were obtained by coated Al-Si nanoparticles with the precursor of glucose (C6H12O6) as the carbon source. It was indicated that the carbon coating on Al-Si nanoparticles can eliminate the negative effects on the electrochemical insertion/extractions of lithium ions, improve the initial capacity and cycle performances.

An Evaluation on Processing of Metal Matrix Composites (Al2O3/AC8A) by Low-Pressure Infiltration

At present many researches are about low density and high strength material, Metal Matrix Composite (MMC) is one kind of high performance material which is very popular and can fit that condition very well. In this study, matrix material is Al alloy and Al2O3 short fiber is reinforcement, volume fractions of Al2O3 short fiber is 10, 15 and 20 %. Manufacture by a low-pressure infiltration method. And the performance is evaluated by microstructure observation, porosity ratio and relative density. It is found that the porosity ratio can be effectively adjusted by the infiltration temperatures and the loads of Al2O3 short-fibres, exhibiting a minimum of 2 for 10% loading at 700°C. Meanwhile, the relative density of composites reached to be a maximum of 98% for 15% loading at 700°C. The low porosity ratio and high density of composites are reasonably attributed to the proper processing techniques.