Papers by Author: Zhi Hong Li

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Authors: Yu Mei Zhu, Zhi Hong Li, Xia Wan Wu
Authors: Kai Gao, Zhi Hong Li, Peng Fei Wang, Xue Song Li, Yu Mei Zhu, Kai Yue Wang
Abstract: Zn and Cu were separately incorporated to the diamond powder and then the compacts were prepared under 5GPa, 1273K. The results showed that Zn was a good additive to prepare polycrystalline diamond by high-pressure and high-temperature (HPHT) because it could inhibit the graphitization of diamond. The element Zn left in the polycrystalline was in the form of ZnO. The photoluminescence spectroscopy showed that there were a series of sharp bands between 310 and 390nm when the excitation was above 200nm. However, the full width at half maximum of the diamond peaks mostly was below 0.5nm. The intensity of sharp band decreased with the decrease of excitation energy and then disappeared at last.
Authors: Zhi Hong Li, Y.H. Zhang, Bing Han, Y.M. Zhu
Abstract: Advanced ceramics has many advantages and great potential of application, but its high machining cost resulted from its high hardness and brittleness limited its application. Grinding with superabrasives is the most suitable and effective way for machining of advanced ceramics. Grinding with vitrified bond CBN wheels is a developing direction of high efficient grinding for engineering ceramics. Grinding of the promising composite ceramics of TZP/Al2O3 with vitrified bond CBN grinding wheels was investigated in this paper. The results showed that higher material removal rates and satisfactory surface finish were achieved, CBN wheels with coarser grit size or with higher CBN concentration had higher grinding ratio. G-ratio increased with the increasing of wheel speed.
Authors: H.F. Zheng, Zhi Hong Li, Y.M. Zhu
Authors: Guang Tao Zhao, Yu Mei Zhu, Zhi Hong Li, Xing Fen Lv
Abstract: A kind of vitrified bond was selected to be sintered with diamond powders to prepare diamond abrasive. The effect of the additive of CeO2 and sintering parameters on the performance of vitrified bond diamond abrasive was investigated. The mechanical properties of diamond abrasives were tested on ZMC-Ⅱ type diamond static strength tester and the interfacial bonding states between diamond powders and vitrified bonds were studied by Scanning Electron Microscopy (SEM). The results indicated that CeO2 improved the performance of diamond abrasive by means of strengthening the bonding between diamond grits and vitrified bond. The admirable diamond abrasive was achieved when the sample was sintered at 800°C holding for 120min.
Authors: Zhi Gang Zhang, Yu Mei Zhu, Zhi Hong Li
Abstract: Eight kinds of materials with diverse pore-forming mechanism were added into the ceramic ingredient of superfinish grinding tool with the same amount, and the specimens were prepared and sintered in the same condition. Their pore-forming abilities in the sintered bodies were compared through several performance tests. By measuring the porosity, bulk density, water absorption and flexural strength of these sintered bodies, and observing the SEM images, pore-forming agents with the best working mechanism was identified. It is proved that those pore-forming agents which have pore structures in themselves process the best pore-forming ability, and they can maintain relatively high porosity and high mechanical strength, which is good for the superfinish grinding tools.
Authors: P.F. Wang, Zhi Hong Li, Y.M. Zhu
Abstract: Alkaline-earth metal oxides (MgO, CaO, SrO and BaO) were introduced to Na2O-B2O3-Al2O3- SiO2 vitrified bond, and their effects on the properties of the vitrified bond were investigated through the measurements of refractoriness, fluidity and bending strength. The results showed the refractoriness of the vitrified bond was reduced and the fluidity of the bond increased with the addition of alkaline earth metal oxides in the order of CaO>SrO>BaO>MgO. When 2-10wt% MgO, CaO and BaO was added into the bond respectively, the vitrified bond was relatively dense due to high viscosity, and the strength was all improved to some extent. However, when more than 4wt% SrO was added, the strength decreased sharply because of the deterioration of microstructure. It was concluded that the bending strength of the bond was affected by alkaline-earth metal oxides in the order of CaO>MgO>BaO>SrO.
Authors: Zhi Hong Li, Y.M. Zhu, Xia Wan Wu, Q.M. Yuan, Zheng Fang Yang
Authors: Ai Ju Zhang, Zi Cheng Li, Zhi Hong Li, Yu Mei Zhu
Abstract: Preparation of high wear-resistant ceramic parts was studied in this paper. The mechanical property was measured by the three-point bending tester, and the microstructures were analyzed with the scanning electronic microscope (SEM). The experimental results showed that vitrified bond CM2 was suitable for the preparation of high wear-resistant ceramic parts because of its lower refractoriness, and higher bonding strength sintering at 850oC. Moreover, containing 8- 12μm CBN abrasive grains, the ceramic parts reached higher strength and higher wear resistance than other samples.
Authors: Ai Ju Zhang, Zhi Hong Li, Zi Cheng Li, Yu Mei Zhu
Abstract: In this paper microcrystalline CBN abrasives are prepared with CBN powders and vitrified bond additives by pressureless sintering method. Mechanical properties of the products are measured by using single particle compressive strength tester and three-point bending strength tester. The effects of vitrified bond additives, the CBN powders particle size and the sintering temperature on the performance of microcrystalline CBN abrasives are investigated. The microstructure characteristics of microcrystalline CBN abrasives are examined. The results showed that the performance and microstructure of microcrystalline CBN abrasives are significantly influenced by particle size of CBN powder and the addition amount of vitrified bond.
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