烧结镁砂外加量对制备Mg-α/β-SiAlON复相材料的影响

Effect of sintered magnesia extra addition on preparation of Mg-α/β-SiAlON composite materials

以烧结镁砂粉、Al粉、Si粉及α-Al2O3粉为主要原料,Y2O3为助烧剂,采用高温氮化法经1550℃保温3 h制备了Mg-α/β-SiAlON复相材料。研究烧结镁砂粉的外加量(质量分数分别为0、20%、40%、60%、80%和100%)对其显微结构和烧结性能的影响。结果表明,随着烧结镁砂外加量的增加,Mg-α-SiAlON相由等轴晶向片状晶转变,引入过量的烧结镁砂粉可以弥补Mg-α/β-SiAlON在氮化过程中镁蒸气的损失;烧结镁砂粉外加量为60%(w)时,Mg-α-SiAlON晶粒的长径比最大,为3.47,Mg-α/β-SiAlON复相材料的质量增加率最大,为16.6%,体积密度为2.30 g·cm^-3。

Mg-α/β-SiAlON composite materials were synthesized by high temperature nitriding at 1550℃for 3 h using sintered magnesia powder,Al powder,Si powder andα-Al2O3 powder as the starting materials,and Y2O3 as the sintering agent.Effects of sintered magnesia powder extra additions(0,20%,40%,60%,80%and 100%,by mass)on the microstructure and the sintering properties of the composite materials were researched.The results show that with the sintered magnesia powder extra addition increasing,the morphology of Mg-α-SiAlON varies from isometric crystal to plate-like.Introducing excessive sintered magnesia powder can compensate for magnesium vapor of Mg-α/β-SiAlON loss during nitriding.Extra adding 60%sintered magnesia,the Mg-α-SiAlON grains have the maximum length-diameter ratio of 3.47,meanwhile,the Mg-α/β-SiAlON composite materials show the highest mass gain ratio of 16.6%and the bulk density of 2.30 g·cm^-3.