Ni、Cu-Al_2O_3纳米金属陶瓷粉末的热压

Hot pressing of Ni-Al_2O_3/Cu-Al_2O_3 cermet nanopowder

将化学电镀法制备的纳米Ni、Cu包覆Al2O3粉末进行热压。研究了金属Ni、Cu及其含量对Al2O3粉末的烧结致密化、显微组织和性能的影响。在纳米Al2O3粉末表面镀覆适当的金属Ni、Cu可以较有效地提高致密化,降低烧结温度。金属相作为第二相可以大大细化Al2O3晶粒组织。但Ni、Cu的加入伴随着Al2O3硬度和强度下降。硬度变化可以由金属Ni、Cu是软相较好地解释。强度下降则主要归因于包覆粉末中Ni、Cu对Al2O3粉末的润湿性不好所致。

Al2O3 nanopowder chemically coated with Ni and Cu was hot-pressed. The influences of Ni/Cu contents on densification, microstructure and properties were studied. Proper content of Ni/Cu coated on the Al2O3 nanopowder can enhance densification effectively, and thus sintered temperature is decreased. The metal phase as a second phase can greatly decrease Al2O3 grain size, but hardness and strength are decreased too. The decrease of hardness is due to the effect of soft metal phase of Ni/Cu. The decrease of strength is attributed to the weak bonding force of Ni/Cu to Al2O3 powders.