摘要
通过DSC,X射线衍射等技术研究了一系列掺杂钙铬酸镧材料的低温相变行为,并对其热膨胀过程进行了分析。发现铬酸镧在240℃左右发生低温相变,在260℃左右结束。随钙含量的增加,相变的开始和终了温度均显著升高,相变属吸热反应。铬酸镧及掺杂铬酸镧材料的低温结构相变均是由正交结构向菱形结构的转变。在相变过程中无明显质量变化,但会发生较大的体积收缩。
The low-temperature phase transformation of LaCrO_3 and doped-LaCrO_3 was studied by DSC and XRD, and thermal expansion during phase trans formation was measured. It is found that the phase transformation of LaCrO_3 begins near 240 ℃ and ends up to 265 ℃. The phase transformation temperature range obviously raises as the Ca content increases. The low temperature transformation changes the crystal structure of LaCrO_3 and Ca-doped LaCrO_3 from orthorhombic to rhombohedral and is a heat-absorbing reaction. There is no weight change but shrink of the sample happened during transformation.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2004年第5期619-622,共4页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金(50362001)
山东省中青年科学家基金(02BS061)项目
关键词
无机非金属材料
铬酸镧
结构相变
热分析
稀土
inorganic nonmetallic materials
lanthanum chromites
phase transformation
heat analysis
rare earths
