Tan Xiao-Ping, Liang Shu-Quan, Chai Li-Yuan, Zhang Guo-Wei, Zhang Yong
College of Metallurgical Science and Engineering, Central South University, Changsha 410083, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2011 Jan;31(1):123-6.
The structural changes in the in-situ controlled crystallizing process of Si-Al-Zr-O(SAZ) amorphous bulk were investigated by laser Raman (LRa), infrared (IR) and X-ray diffraction (XRD) techniques. The structure of the amorphous network apparently reorganized at about 920 degrees C, resulting in the formation of Si-rich and Al, Zr-rich regions. The t-ZrO2 was crystallized from the Zr-rich region at 920-950 degrees C and poorly defined Al-Si spinel was formed from the Al-rich regions. With the increase in temperature, the peak of Al-Si spinel was enhanced and then disappeared in the XRD pattern, and the characteristic IR band groups of mullite centered in the 1 200-1 100, 1 000-700 and 650-400 cm(-1) could be observed. At 1 100-1 150 degrees C, the Raman bands at 179 and 193 cm(-1) typical for the m-ZrO2 occurred and cristobalite was detected, and the main crystalline phases were identified as t-ZrO2 and mullite. These results indicated that mullite was formed by reaction between amorphous silica and the Al-Si spinel which was metastable phase. During the heating process, t-ZrO2 was crystallized firstly and a portion was transformed to m-ZrO2 at high temperature, and the left amorphous silica was transformed to cristobalite.
采用激光拉曼光谱（LRa）、红外光谱（IR）和X射线衍射（XRD）技术研究了Si-Al-Zr-O（SAZ）非晶块体原位控制结晶过程中的结构变化。非晶网络结构在约920℃时明显重组，形成了富硅区和富铝、锆区。t-ZrO₂在920-950℃从富锆区结晶出来，富铝区形成了结晶度较差的Al-Si尖晶石。随着温度升高，XRD图谱中Al-Si尖晶石的峰增强然后消失，并且可以观察到以1200-1100、1000-700和650-400 cm⁻¹为中心的莫来石特征红外波段组。在1100-1150℃，出现了m-ZrO₂典型的179和193 cm⁻¹拉曼峰并检测到方石英，主要晶相被鉴定为t-ZrO₂和莫来石。这些结果表明莫来石是由无定形二氧化硅与亚稳相Al-Si尖晶石反应形成的。在加热过程中，t-ZrO₂首先结晶，一部分在高温下转变为m-ZrO₂，剩余的无定形二氧化硅转变为方石英。
