环境材料的研究及进展

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。     

SPS技术的进展及其在硬质合金制备中的应用

介绍了放电等离子烧结SPS技术的原理、特征、工艺影响因素及发展,并使用放电等离子烧结制备了WC-Co和TiCN系硬质合金,展望了放电等离子烧结在硬质合金制备中的应用。     

高能球磨制备Ti(C,N)基金属陶瓷硬质相超微粉

对Ti(C,N)基金属陶瓷硬质相TiC、TiN、WC原料粉在不同球料比、不同球磨时间试验条件下进行高能球磨,探讨了TiC、TiN、WC粉体的高能球磨超细化机理和球磨行为特征。试验表明随球料比和球磨时间的增加,TiC、TiN、WC粉体得到细化,但达到一个极小值后细化趋于稳定。利用沉降法测试粉末粒度分布并在扫描电镜下观察粉末的形貌和粒度,发现在10∶1球料比下球磨96h后可以有效制备得颗粒粒度为0.20μm的金属陶瓷硬质相超微粉。     

粉末粒度测试方法述评

综述了目前常用的粉末粒度与粒度分布测定方法的原理、特点及适用范围 ,并对粒度测试技术的发展作了展望     

放电等离子烧结制备Ti(C,N)基金属陶瓷

用放电等离子烧结(SPS)技术制备了Ti(C，N)基金属陶瓷材料。使用XRD、SEM对烧结体物相、微观组织进行了分析，并对金属陶瓷的硬度、抗弯强度和孔隙率进行了对比分析。结果表明：SPS工艺下形成了Ti(C，N)相；1350℃下保温8min是较佳的烧结工艺。原料粉添加VC后，烧结体晶粒组织明显细化，但孔隙率变大，综合性能仍高于未添加VC的金属陶瓷。     

粉末分散对Ti(C,N)基金属陶瓷力学性能的影响

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。     

Characterization of phase transformation and microstructure of nano hard phase Ti（C,N）-based cermet by spark plasma sintering

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.