Papers by Author: Y. Wang

Abstract: The bearing support implement is the key component in the precision process of bearings. Diamond films are deposited on Co-cemented carbide bearing support implements using the acetone and hydrogen as the gas source by the bias–enhanced hot filament chemical vapor deposition (HFCVD) technique. Diamond-coated bearing support implements are fabricated and used in the precision grinding of bearings. The research results show that the appropriate pretreatment methods and CVD process can effectively control the morphology, chemical quality, surface roughness, and adhesion of diamond films. As compared with the cemented carbide bearing support implements, the diamond-coated bearing support implements have obviously better wear resistant properties and working performance. It is of great significance for improvement of the bearing processing quality and raising of the bearing processing level.

Abstract: Improving adhesion and surface roughness of diamond films on WC–Co substrate is the key factor of the widespread application of diamond coated tools. A new pretreatment method has been performed for smooth Co-cemented carbide inserts in order to lower the surface roughness of diamond films under the premise of good adhesion between diamond films and substrates. The effect of the new pretreatment on the adhesion of the diamond films is investigated. Research results show that the boronization pretreatment can effectively suppress cobalt diffusion to the surface and avoid catalytic effect of Co at high temperature. This new pretreatment can avoid the surface roughening of inserts and ensure the deposition of smooth diamond films. Investigation shows that the optimum boronization compounding is a powder mixture of 70%B4C+15.5%KBF4+1.5% La2O3+13%Na2CO3. Adhesion between substrates and diamond films is evaluated by Rockwell A indentation tests and the cutting performance of the diamond-coated tools is investigated by the cutting tests. Diamond films on smooth cemented carbide inserts with cobalt boride interlayer have high adhesive strength and low surface roughness. Diamond-coated tools with boronization pretreatment have a 5-fold increase in tool life compared with untreated ones.

Abstract: SiC-particle-reinforced aluminum-based metal matrix composite is one of the important composites among the metal matrix composites, for their various advantages such as lightweight, high specific modulus, specific strength, wear resistance and high temperature resistance. The precision machining of these advanced materials will not be possible without the solution of the grindability problem, which resists wide spread engineering application of PRAlMMCs as precise parts. This paper investigates the grinding performance and burn mechanism of SiC-particle-reinforced aluminum-based MMCs through thesystematical grinding experiments. Grinding characteristics of these MMCs including grinding force, grinding temperature, morphology of ground surface, surface roughness, residual stress, and chemical composition of the surface layer are obtained and analyzed by the various advanced measuring method. Experiment results reveal the varieties of grinding force, grinding temperature and surface integrity with the onset of grinding burn. The grinding burn mechanism can be unveiled by the varieties of grinding properties. Grinding experiments are conducted under different grinding conditions so as to explore the appropriate grinding parameters to obtain good surface integrity. The research results are of great significance for high efficiency and precision grinding of MMCs, thus promote the wide application of these advanced materials on the precise and wearable components.

Abstract: Rapid manufacturing moulds by plasma arc spraying is a new kind of plasma arc machining technology. This technology has many advantages. An experimental apparatus has been set up. The influence of some special factors on the surface quality of work moulds formed by plasma arc spraying have been analyzed and experimentally researched. The micro structure of the interface between master moulds and work moulds shows that work moulds copy geometrically master moulds very well after optimizing processing parameters. Some experimental samples by plasma arc spraying have been obtained. They show that the surface patterns of work moulds match with the ones of master molds very well.