磁铅石结构NdMgAl11O19粉体的合成与晶格热膨胀  

Synthesis and Lattice Thermal Expansion of Magnetoplumbite Structured Neodymium Magnesium Hexaaluminate

作　　者：吴红丹[1,2] 张锦化[3] 周志辉[1] 雷新荣[2] 

机构地区：[1]武汉科技大学,冶金矿产资源高效利用与造块湖北省重点实验室,武汉430081 [2]中国地质大学(武汉)、纳米矿物材料及应用教育部工程研究中心,武汉430074 [3]武汉科技大学、省部共建耐火材料与冶金国家重点实验室,武汉430081

出　　处：《硅酸盐学报》2017年第7期930-934,共5页Journal of The Chinese Ceramic Society

基　　金：纳米矿物材料及应用教育部工程研究中心基金项目(NGM2016KF008)

摘　　要：采用反向化学共沉淀法和高温煅烧法制备了磁铅石结构NdMgAl_(11)O_(19)粉体,并对粉体物相组成、化学成分、显微结构及晶格热膨胀行为进行了表征。结果表明:1 600℃煅烧得到的粉体为磁铅石结构NdMgAl_(11)O_(19),晶体发育良好,晶粒呈规则六方片状,各晶面光滑平整。a、c逐渐增大,与温度呈非线性关系。NdMgAl_(11)O_(19)的晶格热膨胀表现出各向异性,室温~1 300℃,a轴方向的平均热膨胀系数为7.3×10^(–6)/℃,c轴方向的平均热膨胀系数为11.2×10^(–6)/℃。Nd―O键的各向异性膨胀是晶格沿a、c轴方向表现出不同的热膨胀行为的主要原因。The neodymium magnesium hexaaluminate （NdMgAl11O19, NMA） powders were synthesized via a reverse chemical coprecipitation and high-temperature calcination method. The crysstal structure, phase composition, micromorphology, and lattice thermal expansion were characterized. The magnetoplumbite structured NMA powder was obtained via calcination of the precursor at 1 600 ℃, and the morphology of the grain is regular with smooth hexagonal facets. The temperature dependence of the lattice parameters is established, i.e., aT =5.573 68＋4.586×10^-5 T–5.906×10^-8 T2＋4.310×10^-11 T3, cT =21.862 89＋2.7390×10^-4 T–3.186 4×10^-7 T2＋2.306 3×10^-10 T3. The thermal expansion coefficients of NMA from ambient temperature to 1 300 ℃ are 7.3×10^-6 ℃–1 in a-axial direction and 11.2×10^-6 ℃–1 in c-axial direction, respectively. The difference of thermal expansion coefficients in different axis directions is due to the expansion anisotropy of Nd―O bonds.

关 键 词：钕镁六铝酸盐 晶格热膨胀 磁铅石结构 

分 类 号：O614.33[理学—无机化学]