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材料工程  2010, Vol. 0 Issue (3): 22-24,88    
  测试与表征 本期目录 | 过刊浏览 | 高级检索 |
沉淀剂对La2Zr2O7制备过程的影响
王璟, 白书欣, 张长瑞
国防科技大学航天与材料工程学院, 长沙, 410073
Effect of Precipitators on the Formation Process of La2Zr2O7 Powder
WANG Jing, BAI Shu-xin, ZHANG Chang-rui
College of Aerospace and Materials Engineering, National University of Defense Technology, Changsha, 410073, China
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摘要 分别采用氨水和草酸铵作沉淀剂,通过化学共沉淀法制备了单相La2Zr2O7粉末.利用DSC-TGA和XRD等方法对LZ前驱体的煅烧分解过程、产物物相进行了分析和表征.结果表明:氢氧化物前驱体在400~750℃分解得到无定型的复合氧化物,800℃保温2.5h即完成相转变形成单相组分的La2Zr2O7;而草酸盐前驱体在400~650℃草酸盐发生分解得到无定型氧化镧、氧化锆的混合物;700℃以后,La(OH)3的分解、无定型氧化物晶化得到六方结构氧化镧与单斜相氧化锆、Zr4+扩散到La2O3晶界生成La2Zr2O7等三个反应同时进行.获得单相组分La2Zr2O7的煅烧条件至少要1450℃,保温2.5h.草酸盐前驱体中镧和锆两种成分局部的分布不均匀是造成其处理温度比氨水法要高的直接原因.
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王璟
白书欣
张长瑞
关键词 La2Zr2O7化学共沉淀法氨水草酸铵    
Abstract:Single phase La2Zr2O7 powders were synthesized by co-precipitation method using ammonia and oxalate ammonium as precipitant agent,respectively.The process and crystallography characters of these precursors were studied by means of DSC-TGA and XRD.The results show that the hydrate precursor decomposes into amorphous composites of oxides between 400-750℃ followed by crystallization of these oxides.The single-phase La2Zr2O7 is formed just at 800℃ for 2.5h.And the oxalate precursor decomposes into mixture of amorphous oxides at 400-650℃;After 700℃,three reactions,such as the decomposition of La(OH)3,the crystallization of amorphous oxides and the solid state reaction between La2O3 and ZrO2,take place synchronously.The pure La2Zr2O7 from oxalate precursor is not achieved until calcined at 1450℃ for 2.5h.The essence of higher heating temperature for oxalate precursor is pockety La3+ and Zr4+.
Key wordsLa2Zr2O7    chemical co-precipitation    ammonia    oxalate ammonium
收稿日期: 2008-08-25      出版日期: 2010-03-20
中图分类号:  TG174.442  
作者简介: 王璟(1982- ),女,在读博士,从事高温热结构及热防护研究,联系地址:湖南长沙国防科技大学航天与材料工程学院501教研室(410073),E-mail:jingwang@nudt.edu.cn
引用本文:   
王璟, 白书欣, 张长瑞. 沉淀剂对La2Zr2O7制备过程的影响[J]. 材料工程, 2010, 0(3): 22-24,88.
WANG Jing, BAI Shu-xin, ZHANG Chang-rui. Effect of Precipitators on the Formation Process of La2Zr2O7 Powder. Journal of Materials Engineering, 2010, 0(3): 22-24,88.
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