球磨转速对Nd:YAG透明陶瓷的显微结构及光学性能的影响

以高纯商业Y₂O₃、α-Al₂O₃和Nd₂O₃粉体为原料, 以TEOS(正硅酸乙酯)和MgO为烧结助剂, 采用固相反应和真空烧结技术制备了1.0at%Nd:YAG透明陶瓷。系统研究了球磨转速(球磨时间10 h)对混合粉体的尺寸以及对陶瓷样品致密化行为、显微结构和光学性能的影响。结果表明: 通过球磨过程可以充分细化原料粉体的颗粒; 随着球磨转速的提高, 陶瓷烧结时样品中的气孔能更好地排除。但是球磨转速过高时, 陶瓷烧结体中存在少量的富铝第二相会降低样品的光学透过率。当球磨转速为130 r/min时, 真空烧结(1760℃×50 h)所得Nd:YAG透明陶瓷的微结构均匀致密, 几乎没有晶界和晶内气孔存在, 样品在1064 nm处的直线透过率高达83%。

Influence of Ball Milling Speed on Microstructure and Optical Transparency of Nd:YAG Ceramics

Transparent 1.0at%Nd:YAG ceramics were fabricated by the solid-state reaction and vacuum sintering method using Y₂O₃, α-Al₂O₃ and Nd₂O₃ as starting powders. These powders were mixed in ethanol with MgO and TEOS as sintering aids and ball milled at different speeds for 10 h. Effects of ball milling speed on the particle size of powder mixtures as well as the densification process, the microstructure and the optical transparency of Nd:YAG ceramics were mainly investigated. It is showed that coarse powders can be ground into fine particles with increase of the ball milling speed up to 130 r/min. Porosities of the sintered Nd:YAG ceramics decrease with the increase of ball milling speed. Al-rich secondary phase can be observed in the microstructure of Nd:YAG ceramics when the ball milling speed is over-high, and it will cause a decrease in the optical transmittance. For the sample sintered at 1760℃ for 50 h from the powder mixture ball milled at 130 r/min, the in-line transmittance reaches 83% at 1064 nm and there are almost no pores at the grain boundaries and inner grains.