机械合金化3Y_2O_3-5Al_2O_3粉末的研究

PREPARATION OF 3Y_2O_3-5Al_2O_3 POWDER BY MECHANICAL ALLOYING

研究了转速,球磨时间等球磨工艺对3Y2O3-5Al2O3机械合金化过程的影响。结果表明:在较低的转速下(250r/min),提供的球磨能量很低,只会细化粉体颗粒;提高转速(400r/min),会促使Y2O3发生晶型转变,由稳定的立方晶转变成非稳态的单斜晶;继续提高转速(500r/min),还会使混合粉体发生合成反应,生成YAlO3(YAP)。在转速为500r/min,球料比为20∶1的球磨条件下,3Y2O3-5Al2O3粉体发生固相反应的过程可分为两个阶段:第一阶段,Al2O3颗粒晶格畸变,快速细化;同时,高能球磨促使Y2O3发生了晶型转变。第二阶段,Y2O3晶型转变基本完成,并呈无定形化,Y2O3和Al2O3发生合成反应,生成YAlO3(YAP)。但在球磨条件下,难以合成Y3Al5O12(YAG)、Y4Al2O9(YAM)。

Effect of rotation speed and time of ball milling on mechanical alloying（MA）of Y2O3-Al2O3 system was investigated.The result showed that the low rotation speed offers low energy,which can only refine the particles.Inereasing the rotation speed to 400 r/min makes Y2O3 polymorphic transform from stable cubic crystalline to metastable rhombic crystalline;At a rotation speed of 500 r/min the YAlO3（YAP）is synthesized from Y2O3 and Al2O3.At a rotation speed of 500 r/min and ratio of ball-to-powder 20∶1,solid-state reaction of Y2O3 and Al2O3 is divided into two steps,in first stage crystal size is reduced with distortion of crystal lattice of Al2O3.At the same time the ball milling promotes the polymorphic transformation of Y2O3.In the second stage,Y2O3 is transformed thoroughly into amorphous state,and YAP is synthesized by solid-state reaction from Y2O3 and Al2O3.However,it is difficult to form Y3Al5O12（YAG）,Y4Al2O9（YAM）by ball milling.