燃烧法制备La_2O_3纳米晶的研究

以硝酸镧作为氧化剂,柠檬酸铵作为燃料,用少量尿素作引发剂,采用燃烧法制备了La_2O_3纳米晶.并研究了煅烧温度、原料计量比和释放气体等因素对样品的影响.室温固相反应法制得的粘稠膏状络合物LaCit,当加热至150 ℃时立即引起燃烧,得到灰色前驱物,前驱物经700 ℃煅烧2 h得到单晶纳米La_2O_3样品.利用XRD、TEM和SEM测试方法对样品表征,结果表明:样品形貌为透明矩形片状单晶,平均长度为100~150 nm,宽度为40~80 nm,厚度约为20 nm,产率为85;~87;,粒度分布均匀,具有良好的分散性.

Study on Preparation of La_2O_3 Nanocrystalline by the Combustion Method

The nanocrystalline La_2O_3 were prepared by the combustion method, in which the lanthanum nitrate was conducted as oxidant, ammonium citrate as fuel and a little urea as initiating agent. The influences of the factors on product, including calcinating temperature, stoichiometry ratio between materials and release gases were studied. The thixotropic paste complex LaCit was heated and burnt at a temperature of 150 ℃, and then the gray precursor was obtained. The nanocrystalline La_2O_3 was prepared by calcining the precursor at 700 ℃ for 2 h. Then the samples were characterized by XRD, TEM and SEM. The results indicate that the morphology of nanocrystalline La_2O_3 is clarity-rectangled flakes on an average length of 100-150 nm, the width of 40-80 nm and the thichness of 20 nm. The yield of nanocrystalline La_2O_3 is 85%-87% with narrow size distribution and good dispersion of particles.