【作者】 黄永珍；

【导师】 程继贵；

【作者基本信息】 合肥工业大学 ， 材料学， 2007， 硕士

【摘要】 ABO3型钙钛矿复合氧化物是一类重要的无机化合物，可以用作多种功能材料。钛酸锶（SrTiO3）陶瓷作为一种典型的钙钛矿型结构物质，是一种用途广泛的电子功能陶瓷材料。它具有介电损耗低、热稳定性好等特点，可以制造高中压陶瓷电容器和边界层陶瓷电容器、低压压敏电阻器等，广泛应用于电子、机械等行业；同时，SrTiO₃陶瓷具有禁带宽度高（312 eV）、光催化活性优良等特点，在光催化分解水制氢、光催化降解有机污染物和光化学电池等光催化领域也得到了广泛的应用。目前，A位或B位掺杂的ABO₃型钙钛矿结构稀土氧化物是研究热点之一。其中，以碱土金属或稀土金属掺杂SrTiO₃而获得的离子-电子混合导体，在中温下具有较高的电导率和催化活性，并具有较好的化学稳定性和热稳定性。有可能作为燃料电池的阳极催化材料等。掺杂SrTiO₃粉体的制备通常采用固相反应法，固相反应法虽然简单易行，但制备的粉体粒度较粗，活性差，需烧结温度高。在本论文中，采用新颖的湿化学方法——凝胶浇注法（Gel-casting）制备出了Sr_1-1.5xSm_xTiO₃粉体，考察了Sm掺杂量、煅烧温度等对粉体的相组成、形貌、粒度及烧结活性的影响；并对由粉体制备获得的烧结体的性能等进行了表征。结果表明：采用凝胶浇注法制备的粉体颗粒细小均匀、烧结体性能较好；煅烧温度和Sm掺入量对粉体的成相有明显的影响。煅烧温度为1200℃，Sm掺入量为4mol％时，粉体形成单一的钙钛矿结构，所得粉体粒径为1.77μm。1400℃烧结得到的Sr_1-1.5xSm_xTiO₃烧结样品具有较好的孔隙率和力学性能；另外，Sm的掺杂明显提高了掺杂SrTiO3材料的电导率，烧结体在氢气中的电导率高于在空气中的电导率，1400℃烧结体Sr_0.94Sm_0.04TiO₃，800℃时在氢气和空气中的电导率分别为28.2S·cm^-1，0.0041S·cm^-1；掺入少量的Sm，适当控制烧结温度可以改善烧结体的硬度，1400℃烧结Sr_0.94Sm_0.04TiO₃试样的洛氏硬度和抗弯强度最高分别为91.5HRA，825.32MPa。更多还原

【Abstract】 Perovskite oxide is an important kind of inorganic compounds as functional materials. SrTiO₃, as a typical perovskite oxide,is widely used in electronic and mechanical applications for its low dielectric loss and thermal stability. And it can be made into high and middle voltage ceramic capacitors, boundary layer ceramic capacitors and low voltage dependent resistors. SrTiO₃ can also be used in producing hydrogen, degrading polluted organic and photochemical cells Because of its high band gap （312eV） and photo-catalysis activity.At present, ABO₃ oxides doped with rare element in A or B sites become one of hotspots. Sm doped SrTiO₃, a mixed conductor, shows high conductivity, high catalysis activity, good chemical and good thermal stability, This makes it potentially be used as anode materials for solid oxide fuel cells. The powder is usually made by solid-state reaction.The powders is coarse size, poor activity, and a high sintering temperature manufactured by the solid-state reaction.In this dissertation, Sr_1-1.5xSm_xTiO₃ was made by a novel wet chemical way of gel-casting. The effect of Sm content and sintering temperature on phase, powders morphology, particle size and sintering activity were investigated, and the properties of the sintered specimen as-prepared were also tested. The results showed the powders made by gel-casting showed uniform particle size and good properties. Sm content and sintering temperature had greatly affected the phase of powders. The powders sintered at 1200°C with 4mol% Sm doped showed pure perovskite and 1.77μm in size, and Sr_1-1.5xSm_xTiO₃ sintered at 1400°C showed high porosity and mechanical strength. Sm doped into SrTiO₃ evidently improved conductivity, and the conductivity tested in hydrogen was higher than that tested in air. The conductivity of Sr_0.94Sm_0.04TiO₃ sintered at 1400°C in hydrogen and air were 28.2 S·cm^-1 and 0.0041 S·cm^-1 at 800°C, respectively. Sm also made Sr_0.94Sm^0.04TiO₃ show a high Rockwell hardness of 91.5HRA and high bend strength of 825.32MPa.更多还原