Phase Composition Analysis of TiN-AI_2O_3Synthesized from Aluminum-containing Dross and Rutile by Aluminothermic Reductionnitridation Method

TiN- Al2O3 composite powder was prepared by aluminothermic reduction- nitridation method with starting materials of aluminum-containing dross and rutile,and metallic aluminum in the aluminum-containing dross as reducer. The influences of synthesis temperature（600-1 400 ℃） and aluminum-containing dross addition（20% lower than theoretical value,theoretical value,20% higher than theoretical value,and 50% higher than theoretical value） on phase compositions and microstructure of the composites were investigated,and the reaction mechanism was analyzed. The results show that（1） TiN- Al2O3 composite powder can be synthesized under the experimental conditions; the main phases are TiN,α-Al2O3,a little bytownite,and MgAl2O4;（2）enhancing synthesis temperature or increasing aluminumcontaining dross addition favors the reaction of aluminothermic reduction- nitridation;（3） in the synthesized products,α-Al2O3 is platy or columnar; TiN is sub-micron granular,which reinforces and toughens the composite.

晶化硅酸铝纤维增强金属基复合材料

本文研究了非晶态硅酸铝纤维的晶化原理及晶化工艺，以便改善纤维和复合材料的成本和性能，并用Ｘ－射线能谱、Ｘ－射线衍射、电子探针和透射电镜分析技术研究了纤维与铝硅合金的界面反应现象。与非晶态硅酸铝短纤维相比，晶化硅酸铝纤维的显微硬度高，与熔融金属有稳定的化学反应，晶化硅酸铝纤维增强铝硅合金复合材料的高温抗拉强度得到提高。

合成镁铝尖晶石中β″-Al_2O_3结构的研究

采用工业氧化铝和轻烧氧化镁烧结合成镁铝尖晶石(MgAl2O4,MA),当MA中Al2O3含量超过72%(质量分数,下同)时,在晶间生成少量呈板状自形习性的晶体,借助于场发射扫描电子显微镜(field emission scanning electron microscope,FESEM)、能谱仪和X-射线衍射仪研究了晶体形貌和组成。结果表明,该晶体具有与Na2O–MgO–Al2O3系三元化合物组成相同的Mg–β″-Al2O3的晶格常数,特征衍射峰d值分别为1.565 3、0.789 2 nm和0.525 8 nm。样品中Na2O、MgO和Al2O3的组成范围分别为3.1%(质量分数,下同)～4.1%、11.6%～14.4%和81.7%～85.3%。在FESEM的电子束轰击下于β″-Al2O3晶体表面沉析出纳米级微粒金属钠。