Papers by Keyword: Thermal Chemical Polishing

Abstract: Chemical vapor deposition (CVD) diamond thin films are widely used in modern industries. However, due to the nature of polycrystalline, thin films are required to be polished in the final process to increase its surface quality. Thermal-chemical polishing is known for its less processing time and low cost. In this paper, the experiments are carried out to observe the effect of processing conditions such as temperature, rotational speed, polishing pressure, and substrate material on the surface roughness and on the material removal rate of the chemical vapor deposition diamond (CVDD). At the same time, the processing mechanism for this thermal-chemical polishing is investigated, and a polishing model is built for comparison with the experiment results. The results show that the material removal rate is affected mainly by the diffusing rate in the Fe-C polishing system. By using the model, the approximate value of material removal rate can be calculated according to the polishing temperature.

Abstract: Polycrystalline CVD diamond film possesses many advanced physical and mechanical properties which makes it a very important engineering material. However, high hardness value and extreme brittleness have made CVD diamond film a very difficult material to be machined by conventional grinding and polishing processes. In the present research, diamond wafers were pretreated with RIE in an attempt to weaken the top layer and pave the way for subsequent thermochemically polishing. It was found that the diamond grains were anisotropically etched and some high aspect ratio pillar-like micro-structures were formed during the RIE process. These micropillars are relatively easy to be ruptured and removed by the subsequent polishing process. The results showed that this method could effectively speed up the polishing of CVD diamond films.

Abstract: CVD diamond films have been used in many high-tech fields with the industrial and scientific developments, while the lagging of the polishing technology for the CVD diamond films has limited their widely applications. This paper presents a high-efficient low-cost wheel-grinding technology for CVD diamond polishing, and the two key techniques of this technology are introduced in detail based on thermo-chemical polishing technology. Furthermore, wheel grinding technology exhibits a promising perspective for the widely application in the diamond films.

Abstract: Structure-designed free-standing diamond films have been fabricated by DC plasma jet method. The different dominant crystalline surface distributions were obtained under different deposition conditions. The as-grown films were polished by thermal chemical method. For the same crystalline structure, the removal rate was strongly affected by polishing parameters, such as polishing temperature, polishing time and applied pressure. The experimental results also showed that the dominant surface distribution in the films affected the polishing removal rate very much.