钇铝石榴石晶体的机械抛光工艺

摘要

Yttrium aluminum garnet (YAG) is a kind of excellent laser crystal,while it is a hard-brittle material with Mohs hardness of 8.5.In order to remove the defects such as scratches and pits easily produced during the polishing,copper plate was used as rough polishing and the effect of load and rotational speed on the flatness and surface roughness RMS was studied.Results show that copper plate can obviously improve the surface defects of YAG,and that the optimized parameters are rotation speed 70 r/min,load 15 kPa for 45 min.Then IC1000 was used to further reduce crystal surface roughness,and the best process are rotational speed 9 r/min and polishing pressure 15 kPa for 30 min polishing.At such condition,the flatness can reach around 100 nm and the surface roughness RMS can reach around 0.9 nm,with no scratches and pits observed under the stereo microscope.The proposed process could be a good reference for YAG polishing.%钇铝石榴石(yttrium aluminum garnet,YAG)是性能优良的激光晶体,但其属于硬脆材料(莫氏硬度8.5),在抛光时易产生划痕及凹坑等缺陷.为去除YAG晶体的表面缺陷,用铜盘进行粗磨,并研究载荷和抛光盘转速对晶体平面度和表面粗糙度的影响.结果显示:铜盘可改善晶体表面缺陷,在转速70 r/min、载荷15 kPa时抛光45 min可达到最佳加工效果.再使用IC1000进一步降低晶体表面粗糙度,在抛光盘转速为9r/min,抛光压力为15 kPa的条件下抛光30 min后,平面度PV可达100 nm,表面粗糙度RMS可达0.9 nm,在体视显微镜下观察无划痕及凹坑.