Abstract: The present paper is focused on ceramic–metal composites obtained via different
technologies which leads to different microstructures in terms of size and distribution of metal phase. Composites analysed in paper were produced by the following methods:(a) infiltration of porous ceramics by metal, (b) consolidation under high pressure and (c) sintering of ceramic powder coated by metal. Their microstructures were investigated by scanning and transmission electron microscopy methods. The three methods of composite fabrication employed in the present study result in specific spatial distribution and dispersion of metal phase. Presureless infiltration of porous ceramics by liquid metal is driven by capillary force and make it possible to produce microstructure with percolation of metal phase in ceramic matrix. The volume fraction of metal phase in this case depends on the size
of pores. The size of pores influence also the kinetics and extent of infiltration. Ceramic preforms with small size of pore are not fully infiltrated. This method is useful for composite with size of metal phase in the range of micrometers. Hot pressing under high pressure produces microstructures of composites with metal phase grain size in the range from nano to micrometers. Moreover, it allows to achieve the nanometric size of ceramic grains. In the case of ceramic powders covered by metal, compression and hot pressing preserves nanometric size of metal. The grain growth of ceramic grains is suppressed.
Authors: Yong Xing Tong, Li Qin Wang, Le Gu, Bo Peng
Abstract: The friction and wear behavior of Si3N4, SiC and ZrO2 sliding against M50 bearing steel under vacuum condition at various applied load were investigated. The results showed that the properties of different ceramic materials cause the difference in wear behaviors. The coefficient of friction was lowest in SiC and M50 bearing steel couple than other cases for graphitic carbon replaced carbidic carbon at the worn layer of SiC. The specific wear rate of ZrO2 was highest and the lowest was Si3N4. The ceramic ball materials have transferred on M50 bearing steel surfaces and tribofilm consistently formed on the ceramic balls wearing surfaces. Dominant wear behaviors for three structural ceramics were adhesion abrasion, plastic deformation and brittle fracture. The couple with Si3N4 and M50 showed the best operating conditions for friction and wear resistance under higher applied load.
Authors: Dong Dong Huang, Qiu Hong Yang, Yong Gang Wang, Hao Jia Zhang
Abstract: Highly transparent (Ho0.01La0.10Y0.89)2O3 transparent ceramics were fabricated by the conventional ceramics processing with nanopowders. The microstructure, the optical properties and the spectroscopic properties of (Ho0.01La0.10Y0.89)2O3 ceramics were investigated. (Ho0.01La0.10Y0.89)2O3 ceramics with the grain size of ~50 μm were obtained by sintering at 1530 °C for 45 h. The highest in-line transmittance reaches 65%. The emission peak located at 2 μm wavelength indicates (Ho0.01La0.10Y0.89)2O3 transparent ceramics is suitable for 2 μm laser gain medium.
Authors: Yun Yun Xu, Xin Nian Li, Shan Dan Zhou, Tao Zhang, Zheng Ming Li
Abstract: Inorganic non-metallic materials are indispensable and fundamental materials to develop modern industry, agriculture, national defense and science and technology. With the recovery and development of global economy, inorganic non-metallic materials come close to important program opportunity. This paper reviewed recent development on inorganic non-metallic materials technology and industry and analyzed development trend, aimed at providing references for development on inorganic non-metallic technology and industry in Jiangxi province.