烧结温度对TiB2-AIN材料的结构与性能的影响

采用热压烧结制备了TiB2-AIN陶瓷材料,研究了不同烧结温度(1700-1900℃)对用5%体积分数AIN作添加剂的TiB2陶瓷材料的结构和性能的影响.结果表明:在压力为30MPa,保温保压1h条件下随着烧结温度的升高材料的机械性能先上升后下降,在1800℃得到的材料性能最好.     

放电等离子烧结过程温度场及原子扩散

对放电等离子烧结不同材料过程中的温度场进行了理论分析和实验研究,发现在一定条件下样品内出现较大的温差,控制工艺参数可以降低温差.对放电等离子烧结过程中材料界面和颈部的原子扩散过程进行了研究,并与相同工艺条件下辐射加热烧结进行比较,表明放电等离子烧结过程促进了原子的扩散.     

机械方法制造超微粉体的可能、优点及发展现状

本文分析了各种机械方式进行粉磨作业的机理和优缺点,指出目前所用的一些传统粉磨设备输给粉料的能量都不能适中,所以粉磨效果不好.讨论了助磨剂的作用机理,由于助磨剂的使用使得机械方法进行超微粉碎变成了可能.超微粉碎中发生的机械力化学现象可以大大增加微颗粒的化学活性.因此,制造超微颗粒时,不能只简单地将尺寸大小作为一种量度,对机械方法制得的粉体,还应该考虑其机械力化学效应产生的效果.文章最后例举和分析了几种人们正在研究的超微粉碎机械设备.     

硼化物助烧剂对TiB2陶瓷烧结及力学性能的影响

通过在ＴｉＢ２中加入少量的过渡金属硼化物添加剂,使之与ＴｉＢ２固溶复合,并制备出具有较细晶粒的ＴｉＢ２材料,与同等条件下烧结的ＴｉＢ２材料相比,材料强度,韧性均有显著提高。显微结构观察表明;裂纹偏转为主要增韧机理,而强度的提高则得益于其细的晶粒结构和高的烧结密度。     

自蔓延高温合成细晶六硼化钙陶瓷粉末(英文)

基于Mg–B2O3–CaO原料体系,采用自蔓延高温合成(self-propagating high-temperature synthesis,SHS)和后期酸处理工艺,制备出高纯度、均匀分布、小粒径的立方晶型细晶六硼化钙粉末。分析了Mg–B2O3–CaO自蔓延高温反应体系的燃烧产物成分及反应机理,测量了不同SHS反应物原始坯体成型压力的燃烧温度曲线,探讨了不同镁掺量和不同气氛对燃烧产物成分和形貌的影响。研究了原始坯体成型压力与最终CaB6产物粒径的关系。结果表明:采用氩气保护能抑制镁挥发;合适的原始坯体压力有利于合成分布均匀的细晶CaB6粉末。     

试述永磁材料及软磁材料的研究进展

永磁材料和软磁材料是磁性材料中的两大类主要磁性材料,本文在综述磁性材料的基础上,较详细地阐述了永磁材料和软磁材料在国内外的研究进展情况,并展望了其发展趋势。     

层状复合陶瓷研究进展

综合评述了层状复合陶瓷的一些研究进展,同时讨论了层状复合陶瓷的断裂特性,包括几种主要的增韧机制和影响因素。最后,对如何设计层状陶瓷作了一个总结！     

ZnO纳米晶的合成、掺杂及发光性能研究

以Zn(NO_3)_2、(NH_4)_2CO_3与Y(NO_3)_3为初始原料,采用水热法制备了棒状和枝状ZnO及掺杂Y的ZnO纳米晶.采用XRD、Raman、FESEM 、EDAX和PL方法对合成产物形貌与发光性能进行表征.XRD与Raman的研究结果表明,合成的棒状和枝状ZnO纳米晶为六方纤锌矿单晶;XRD与FESEM的测试结果表明,pH值对水热产物的晶相及形貌有重要的影响;XRD结合EDAX的分析结果表明,热处理后的水热产物中Y元素掺入了ZnO基体;ZnO及ZnO-Y_2O_3的纳米晶PL谱的结果表明,产物的发光性能与制备方式有关,与此同时,ZnO-Y_2O_3纳米晶的本征发光峰发生红移,其结果与Y元素与ZnO之间的能量传递有关.     

Diffusion bonding of Ti-6Al-4V by pulse current heating and hot-pressing

Pulse current heating （PCH） was used to join Ti-6Al-4V alloy at two cases of with die and without die. Hot-pressing （HP） method was used to provide a comparison between the two methods. Microstructures near the contacting surfaces were observed in optical microscope. Temperature distribution was analyzed. After joining, the tensile properties of the samples were evaluated. Experimental results show that grains and phases grow transversely on contacting surfaces, which makes two parts into a whole with a certain of tensile strength. PCH joining is a different temperature joining method. The highest temperature is located at the interface. The comparison of tensile strengths of samples joined by the two methods indicates that joining temperature and holding time needed by PCH are lower and less than those needed for HP.     

Fabrication of nano Rhizama Chuanxiong particles and determination of tetramethylpyrazine

Rhizama Chuanxiong is a kind of traditional medicinal herb used to promote blood circulation and eliminate wind to relieve pain. In this work, nano Rhizoma Chuanxiong particles were successfully prepared by high speed centrifugal sheering （HSCS） pulverizer. The influence of processing parameters on the size ofRhizama Chuanxiong particles and the different properties between nano Rhizoma Chuanxiong particles and original fine powder were systematically studied by ZetaPALS light scattering granulometric analyzer and optical microscope. The content of effective ingredient tetramethylpyrazine （TMP） was determined by high-performance liquid chromatography （HPLC）. The results illustrate that general Rhizama Chuanxiong powder can be ultrafinely ground to nanometer within 50 min, and the cellular tissues ofRhizoma Chuanxiong are broken into pieces and dispersed stably and homogeneously after being ultrafinely ground. In addition, the active ingredients can dissolve out directly and fully, and the extraction ratio of TMP is increased 32.2% by HSCS processing.