Papers by Author: Chuang Tian Chen

Abstract: The anisotropy of LBO crystal leads to the different properties of different crystal faces, such as thermal expansion coefficient, which results in trouble of ultra-precision machining. Chemical mechanical polishing of a face (001), b face (010) and c face (001) of LBO crystal by adopting Logitech PM5 Precision Lapping & Polishing Machine in the same process conditions was investigated. The effect of anisotropy on MRR and surface roughness was studied. In the same CMP process conditions, c face of LBO crystal is the highest MRR, b face is inferior to and a face is the lowest. And surface roughness of c face is the best, b face is followed and a face is the worst. The results also show that the anisotropy leads to the different MRR and surface roughness on different crystal faces. In CMP of LBO crystal, the higher MRR is, and the better surface roughness is in the scope of experiment.

Abstract: Transparent Nd:YAG ceramics which are very hard and brittle materials, are very difficult to be polished. There are many micro scratches or damages on the surface after mechanical polishing with Al2O3. In order to remove micro scratches or damages, chemical mechanical polishing (CMP) was adopted to manufacture Nd:YAG ceramics. In the polishing experiment, Pellon and Chemcloth pads were utilized for chemical mechanical polishing of Nd:YAG ceramics. Colloidal SiO2 was selected as the polishing slurry in two different polishing environments, acidity and alkalinity. The surface roughness was determined by using atomic force microscope. In this study, four polishing experimental combinations that each combination contains one of the two pads and one of the two polishing environments were carried out in the optimum polishing condition. Then the high quality surface of transparent Nd:YAG ceramics with the best surface roughness of < 0.2 nm RMS and few micro scratches or damages is obtained by adopting CMP process with Chemcloth pad and colloidal SiO2 in acidic condition.