Al2O3/Mo纳米粉末模压成形烧结及其动力学

摘要

对Mo和Al 2 O 3/Mo纳米粉末进行模压成形，研究纯Mo和Al 2 O 3/Mo压坯在1700~2000℃温度范围内的等温烧结过程，并结合烧结模型分析材料烧结过程中的动力学；利用SEM和TEM分析复合材料的显微组织。结果表明：压坯密度与Al2O3的加入量有关，高温烧结时Al2O3/Mo复合材料的致密度高于纯Mo的致密度；在Al2O3/Mo复合材料烧结过程中，烧结机制既有体积扩散又有晶界扩散，且随着Al2O3含量的增加，晶界扩散趋势明显；纯Mo和Al 2 O 3体积分数为5%、10%和15%Al 2 O 3/Mo复合材料的烧结激活能分别为254.24、234.04、221.40和164.37 kJ/mol；Al 2 O 3的加入可促进晶粒的均匀化和组织的细化。%By molding formation, the isothermal sintering processes of pure Mo and Al 2 O 3/Mo green compact were investigated in the temperature range of 1 700−2 000℃. And combined with sintering model, the sintering kinetics was studied. The microstructures of the composites were analyzed by SEM and TEM. The results show that the green compact density and the adding amount of Al 2 O 3 are related, and the composite density is higher than that of pure Mo in high temperature sintering process. During Al 2 O 3/Mo composite sintering process, the sintering mechanism is proved to contain volume diffusion and grain boundary diffusion, and with the increase of Al 2 O 3 content, the latter trend is obvious. The sintering activation energies of pure Mo and Al 2 O 3 composites with volume fractions of 5%, 10% and 15% are 254.24, 234.04, 221.40 and 164.37 kJ/mol, respectively. The addition of Al 2 O 3 can promote the uniformity and refining for the grains.