(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 采用化學(xué)沉淀法制備了La2Zr2O7(LZ)和CeO2-La2O3-ZrO2(LCZ)陶瓷粉末。通過電感耦合等離子體原子發(fā)射光譜(ICP-AES)、X射線衍射、DSC及霍爾流速計等分析方法，對粉末的化學(xué)組成、不同CeO2摻雜量LCZ的相組成、不同煅燒溫度下的相組成、高溫相穩(wěn)定性和流動性能進行了研究。結(jié)果表明：所制備粉末的組成與鋯酸鑭燒綠石相的組成相近；熱處理溫度600 ℃時粉末為無定形的混合氧化物，900 ℃時轉(zhuǎn)化為復(fù)合氧化物，1 150 ℃時轉(zhuǎn)變?yōu)閱我坏匿喫徼|燒綠石相；高溫下LCZ無明顯相變；溫度高于1 400 ℃煅燒后，LCZ的流動性顯著改善，可用于等離子噴涂。
關(guān)鍵字: 鋯酸鑭；復(fù)合陶瓷；熱障涂層；化學(xué)沉淀法
powder by chemical precipitation method
（School of Materials Science and Engineering, Central South University,
Changsha 410083, China）
Abstract:Lanthanum zirconate (La2Zr2O7, LZ) and CeO2-La2O3-ZrO2 (LCZ) composite ceramic powders were prepared by the chemical precipitation. The chemical composition of the powders was analyzed by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The crystallogrphic phases of LZ and LCZ with different CeO2 doped concentrations were determined by X-ray diffractometry. Differential scanning calorimetry (DSC) and TG were used to analyze the phase stability of LCZ sintered at different temperatures. The Hall flow meter was performed to determine the flowability of LCZ powder. The results show that the compositions of all prepared ceramic powders are similar to that of La2Zr2O7 with pyrochlore structure, the ceramic powders are amorphous mixed oxide at 600 ℃, the amorphous mixed oxide is converted to composite oxide when temperature rises to 900 ℃, and the composite oxide is converted to single La2Zr2O7 with pyrochlore structure at 1 150 ℃. The LCZ powders keep pyrochlore structure and no phase transformations occur for LCZ at high temperatures (1 350 ℃). The flowability of LCZ powder sintered at 1 400 ℃ is improved clearly, and which could be used in plasma spray coatings.
Key words: lanthanum zirconate; composite ceramics; thermal barrier coatings; chemical precipitation
