纳米氧化锆/铂复合材料的微观组织和力学性能

Microstructure and Mechanical Properties of Nano-ZrO_2/Platinum Composite

用锆盐的前驱物(ZrO(OH)2)胶体与氯铂酸铵均匀混合,经过高温烧结,得到纳米ZrO2均匀分布于铂的坯料,再通过压力加工方法制成纳米氧化锆/铂复合材料(纳米ZrO2/Pt)的试样。用金相显微镜,扫描电镜(SEM)观察发现,纳米ZrO2颗粒可明显细化基体铂。纳米ZrO2/Pt复合材料的拉伸断口形貌也与纯铂明显不同。在高分辨透射电子显微镜(HREM)下观察可见,ZrO2颗粒周围铂原子排列发生了扭曲,由此导致铂的力学性能发生很大变化,纳米ZrO2/Pt复合材料的抗拉强度(sb)达470MPa,1400℃下的拉伸强度(sb)达15MPa,断裂伸长率(d)为20%,硬度(HV)为940MPa,分别是纯铂的3.6倍,10倍,0.5倍和2.3倍。

The precipitate of colloidal zirconia and ammonium chloroplatinate mixed sufficiently was sintered at high temperature, and then the sample was prepared by rolling and drawing. The fracture morphology and microstructure of the samples were observed by metallograph, SEM, and HREM. The results show that the nano-ZrO2/Pt grain was refined and its fracture was obviously different from that of pure platinum. The platinum atomic arrangement around the nano-ZrO2 particle was dislocated, which results in great change of the mechanical propereties. The tensile strength of the nano-ZrO2/Pt is 470 MPa at room temperature, 15 MPa at 1 400degreesC, elongation is 20% in annealed condition and Vickers hardness is 940 MPa which is 3.6, 10, 0.5 and 2.3 times, respectively, as compared with that of pure platinum.