机械法制备超细氧化铝粉体及其在ZTA陶瓷上的应用

MECHANICAL PREPARATION OF ULTRA-FINE POWDER OF ALUMINA AND ITS APPLICATION IN ZTA CERAMIC

采用机械研磨不同时间制备不同粒级的氧化铝(Al2O3)超细粉体,将该超细粉体应用于制备氧化铝-氧化锆(Al2O3-ZrO2,ZTA)复相陶瓷,研究了该超细粉体对ZTA复相陶瓷性能的影响。用氮气吸附法测量Al2O3粉体的比表面积,用X射线透射沉降粒度仪、电超声粒度仪测定Al2O3粉体的粒径。研磨实验结果表明:微米级氧化铝原料经研磨可得到亚微米和纳米粒级产品,其中纳米Al2O3粉体平均粒径为70nm,比表面积大于115m2/g;X射线衍射表明:Al2O3晶形未发生变化,随着研磨时间的增加,Al2O3结晶度会降低、各晶面受到不同程度的破坏、晶相仍然是α相。将研磨制备的Al2O3超细粉体与15%(质量分数)的ZrO2复合并在不同温度下烧结ZTA陶瓷。经测试,ZTA在1550℃烧结后,其体积密度最高可达到99%以上,抗弯强度最高可达到720MPa,断裂韧性最高可达到6.86MPa·m1/2,其机械性能优于用化学法制备的氧化铝超细粉体与15%(质量分数)的ZrO2复合的ZTA陶瓷。

This study focused on the fabrication of zirconia-toughened alumina（ZTA） composite ceramic prepared with ultra-fine alumina（α-Al2O3） powders with various sizes prepared by mechanical milling and nano-sized zirconia.The specific surface area of the particles was measured by nitrogen adsorption method.The particle size of the ground products was determined by X-ray transmission particle size analyzer and acoustic particle sizer.The crystal lattices were analyzed using X-ray diffraction（XRD）.The results show that the milling can produce submicron-sized and nano-sized products.The average size of the nano-sized product obtained in the mill was 70 nm with the specific surface area 〉115 m2/g.The main crystal planes of the ground particles were damaged in varying degrees,and the phase was still α-phase.Furthermore,the ultra-fine powder of alumina prepared by mechanical milling was used to compounded with zirconia of 15%（in mass） for sintering the ZTA composite ceramic at different temperat ures.The relative density was 〉 99%,the bending strength reached 720 MPa,and the fracture toughness reached 6.86 MPa·m1/2 after being sintered at 1 550 ℃.The mechanical property of ZTA composite ceramic with ultra-fine alumina powder prepared by mechanical milling was better than that with ultra-fine alumina powder prepared by chemical method.