控制纳米二氧化钛晶型的方法及由此得到的纳米二氧化钛

本发明涉及一种通过氧空位催化相转变控制纳米二氧化钛晶型的方法以及由此得到的纳米二氧化钛。本发明方法可以根据需要得到晶型完全可控的纳米二氧化钛，并克服了二氧化钛在相变温度跨越范围较大时造成晶粒粒径生长很大、难以满足纳米尺度的问题。

Phase transitions, micro-morphology and its oxidation mechanism in oxidation of ilmenite (FeTiO_3) powder

Phase transitions, morphology changes, and oxidation mechanism of the ilmenite oxidation process were investigated. FeTi03 transforms to hematite and rutile when oxidation at 700-800 ℃, and pseudobrookite is formed when the oxidation temperature reaches 900 ℃. The initial ilmenite powder exhibits paramagnetism; however, after being oxidized at the intermediate temperature （800-850 ℃）, the oxidation product exhibits weak ferromagnetism. The oxidation mechanism was discussed. The microstructure observations show that a lot of micro-pores emerge on the surfaces of ilmenite particles at the intermediate temperature, which is deemed to be caoable ofenhancin~ the mass transfer ofoxgen during oxidation.

(Ba_(1-x)Sr_x)(Zn_(1/3)Nb_(2/3))O_3微波介质陶瓷微结构对介电性能的影响

采用传统的固相烧结法制备(Ba1-xSrx)(Zn1/3Nb2/3)O3微波介质陶瓷,研究微结构对介电性能的影响。随着系统中Sr2+含量的增多,介电常数和温度系数发生异常呈现非线性变化,这是由于氧八面体的畸变而导致的相转变造成的,相转变的发生相应影响了极化以及极化模式。相转变及氧八面体畸变对介质损耗没有明显的影响,介质损耗受到Sr2+含量及烧结温度的影响较大。