镍基Al_2O_3-TiB_2金属陶瓷粉末机械合金化机制研究

Mechanism of Mechanical Alloying of Ni Based Al_2O_3-TiB_2 Metal Ceramic Powder

本文研究了添加不同质量分数的Ni对机械合金化合成Al_2O_3-TiB_2金属陶瓷粉末的影响。应用X射线衍射仪、扫描电镜对球磨不同时间后的产物进行了物相和颗粒形貌的分析。结果表明:不含Ni粉的Al、TiO_2和B_2O_3的混合粉末,在机械合金化12 h后,按照化学方程式10Al+3TiO_2+3B_2O_3=5Al_2O_3+3TiB_2发生固相反应,获得Al_2O_3、TiB_2复相组织;当加入Ni粉后Al、TiO_2和B_2O_3的混合粉末,由于在机械球磨过程中,Ni优先与Al形成中间相NiAl,NiAl比Al更容易与TiO_2及B_2O_3发生反应,按照化学方程式10NiAl+3TiO_2+3B_2O_3=5Al_2O_3+3TiB_2+10Ni发生固相反应,获得Al_2O_3、TiB_2复相组织;使得机械合金化时间随着Ni粉加入量的增大而减小,当添加质量分数为5%、10%、15%、20%、25%和30%的Ni粉后,分别在机械合金化12 h、10 h、8 h、8 h、6 h和4 h后,得到Al_2O_3、TiB_2复相组织。

The effect of different amounts of Ni on mechanical alloying synthesis Al_2O_3-TiB_2 cermet powder was studied. Using X-ray diffraction phase analysis（ XRD） and scanning electron microscope（ SEM） studied the changes of phase and particles morphology,which ball milling different time. The results showed that according to the equation 10 Al ＋ 3TiO_2＋ 3B_2O_3= 5Al_2O_3＋ 3TiB_2,without adding Ni powder into the mixed powders which are composed of Al,TiO_2 and B_2O_3 can synthesis Al_2O_3 and TiB_2 by mechanical milling for 12 h. When Ni powder is added,Ni and Al react preferentially and form an intermediate phase NiAl. NiAl more easily react with TiO_2 and B_2O_3than that of Al. According to the chemical equation 10 NiAl ＋ 3TiO_2＋ 3B_2O_3= 5Al_2O_3＋ 3TiB_2＋ 10 Ni,the solid phase reaction occur,produce Al_2O_3、TiB_2 composites,making the required mechanical alloying time decrease with the increase of Ni powder added. Adding 5%,10%,15%,20%,25% and 30% of Ni,got Al_2O_3 and TiB_2 after mechanical alloying 12 h,10 h,8 h,8 h,6 h and 4 h.