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环境材料的研究及进展 总被引:8,自引:1,他引:7
综述了一个新的材料科学研究方向-环境材料,简述了环境材料的概念,分类,评价方法以及环境材料学的概念,介绍了几种应用广泛的环境材料,最后对环境材料在我国的研究及发展做了介绍和展望。 相似文献
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粉末分散对Ti(C,N)基金属陶瓷力学性能的影响 总被引:1,自引:0,他引:1
由平均粒径为0.2μm的TiC,TiN细粉,经1430℃,1h真空烧结制备了Ti(C,N)基金属陶瓷。由扫描电镜和强度、硬度测量研究了金属陶瓷的微观结构和性能。原料粉末以聚氧乙烯十二烷基醚为分散剂.蒸馏水为液体介质,溶液pH值保持在6~7之间,并使用超声波分散,悬浮液过筛后烘干。扫描电镜分析表明:经分散后的粉末颗粒团聚较少、分散良好。分散后细粉以相同工艺制备得Ti(C,N)基金属陶瓷。与未分散细粉烧结体对比表明:由分散细粉获得的金属陶瓷的硬度、抗弯强度均优于未分散细粉制备的烧结体,前者的硬度HRh为90.2,抗弯强度为2108MPa;后者分别为89和1983MPa,其微观结构特征为存在较多的细小均匀的黑芯白壳包覆层结构。细粉分散后,颗粒大小的分布较均匀而影响了液相烧结中的溶解-析出过程,这是金属陶瓷微观结构和性能得到改善的重要原因。 相似文献
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By means of optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM), the process of densification, the characterization of phase transformation and the microstructure for spark plasma sintering (SPS) nano hard phase Ti(C, N)-based cermet were investigated. It is found that the spark plasma sintering (SPS) enables the nano hard phase Ti(C,N)-based cermet to densify rapidly, however, the full densification of the sintered samples can not be obtained. The rate of phase transformation is significantly quick.When being sintered at 1 200℃ for 8 min, Mo2C is completely dissolved, and TiN dissolves into TiC entirely and disappears. Above 1200℃, Ti(C,N) begins to decompose and the atoms of C and N separate from Ti(C,N) resul-ting in the generation of N2 and the graphite. Due to the denitrification and the graphitization, the density and the hardness of sintered samples are rather low. The distribution of grain size of the sample sintered at 1350℃ covers a wide range of 90-500 nm, and most of the grain size are about 200 nm. The hard phase is not of typical core-rim structure. Oxides on the surface of particles can not be fully removed and present in sample as titanium oxide TiO2.Graphite exists in band-like shape. 相似文献
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