Papers by Keyword: Silicon Nitride Ceramics

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Authors: Chuan Zhen Huang, M. Li, Sui Lian Wang, Jing Sun, Han Lian Liu, Xing Ai
Authors: He Zhuo Miao, Zhi Jian Peng, Wen Jie Si, Long Hao Qi, Wen Zhi Li
Authors: J. Yuan, T. Shioya, N. Takeda
Authors: Tarou Tokuda, Mitsuo Kido, Rong Guang Wang, Gonojo Katayama, Fumihiro Suzumura
Authors: Liang Wang, Chuan Zhen Huang, Jun Wang, Hong Tao Zhu, Peng Yao
Abstract: A new processing technology is used in micromachining silicon nitride ceramics for improving the processing efficiency. Laser-assisted waterjet machining technology with near damage-free plays an important role in reducing the heat-affected zone (HAZ). In order to understand the effects of process parameters, such as pulse energy, waterjet offset distance and water pressure, on microgrooving of silicon nitride ceramics and the machining performance, a full-factorial experiment with the comparison experiment has been carried out in this study for analyzing and discussing the groove geometry, the surface quality and HAZ width. It can be concluded that the laser-assisted waterjet processing technology can expel more material removal with near damage-free.
Authors: Paul F. Becher, Gayle S. Painter, Naoya Shibata, Hua Tay Lin, Mattison K. Ferber
Abstract: Silicon nitride ceramics are finding uses in numerous engineering applications because of their tendency to form whisker-like microstructures that can overcome the inherent brittle nature of ceramics. Studies now establish the underlying microscopic and atomic-scale principles for engineering a tough, strong ceramic. The theoretical predictions are confirmed by macroscopic observations and atomic level characterization of preferential segregation at the interfaces between the grains and the continuous nanometer thick amorphous intergranular film (IGF). Two interrelated factors must be controlled for this to occur including the generation of the elongated reinforcing grains during sintering and debonding of the interfaces between the reinforcing grains and the matrix. The reinforcing grains can be controlled by (1) seeding with beta particles and (2) the chemistry of the additives, which also can influence the interfacial debonding conditions. In addition to modifying the morphology of the reinforcing grains, it now appears that the combination of preferential segregation and strong bonding of the additives (e.g., the rare earths, RE) to the prism planes can also result in sufficiently weakens the bond of the interface with the IGF to promote debonding. Thus atomic-scale engineering may allow us to gain further enhancements in fracture properties. This new knowledge will enable true atomic-level engineering to be joined with microscale tailoring to develop the advanced ceramics that will be required for more efficient engines, new electronic device architectures and composites.
Authors: Jie Zhang, Lin Bin Zhu, Bao You Zhang, Shi Wei Yang
Abstract: Si3N4 and 40CrMo steel was joined using Ag-Cu-Ti-Pd brazing filler. Microstructure of the joint and bonding interface was studied by SEM and EDS, and the phase structure was analyzed by XRD. The results indicate that reaction layers at ceramic/ filler alloy and filler alloy/steel interfaces are formed. There is a reaction layer containing TiN and Ti5Si3 between ceramic and filler alloy, while the reaction layer between filler alloy and steel is composed of Fe-Ti compound. The middle part of the joint is an eutectic structure composed of Ag-riched and Cu-riched solid solutions. With the increase of the brazing temperature, the thickness of the joint seem decrease, the thickness of the reaction layer between Si3N4 and filler alloy increases and then decreases, and the thickness of the reaction layer between filler alloy and steel increases.
Authors: Orsolya Koszor, Andre Lindemann, François Davin, Csaba Balázsi
Abstract: Thermophysical and tribological measurements have been performed on carbon nanotube added silicon nitride composites. Higher thermal conductivity values were observed in the case of the sample with CNT than for the reference sample. As was observed from tribological measurements, nanocomposite Si3N4 without carbon nanotubes shows a higher friction coefficient than carbon nanotube - Si3N4. The results of wear study indicate that the Si3N4 ball (used as static partner) was more damaged with MWCNTs addition nanocomposite than with pure Si3N4 ceramic. A pronounced difference was observed in the wear rate: there was a much higher wear for carbon nanotube - Si3N4 than for Si3N4 without MWCNTs.
Authors: Cong Rong Zhu, Ju Long Yuan, Qin Xu, Bing Hai Lv
Abstract: Silicon nitride ceramics materials have excellent properties such as small density, high rigidity, high Young's modulus, high wearability, good thermal stability and chemical stability, which make it become one of the most appropriate materials for rollers of high precision bearing. Chemical Mechanical Polishing (CMP) technology is employed to have an ultra-precision machining process for silicon nitride ceramics materials workpiece and the effects of workpiece surface roughness in different abrasive are discussed in this research. The XRD and SEM technology are used to take phase analysis and surface profile detection for the finishing workpiece polished with CeO2 abrasive. The chemical reaction mechanism and the material remove mechanism of silicon nitride ceramics materials in CMP process with CeO2 abrasive are both analysed and discussed in this paper. The research result shows that an extremely smooth surface of silicon nitride ceramics materials workpiece with roughness 5nm Ra is obtained after CMP process with polyurethane polishing pad and CeO2 abrasive.
Authors: A. Kaiser, H.-J. Richter, Mathias Herrmann, W. Hermel
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