Study on Hydro-thermal Processing of Cubic Boron Nitride by Laser Beam Irradiation

当固体材料在有水存在的情况下被激光束照射时，它们被加热到高温，预计固体材料与水产生的自由基之间会发生进一步的化学反应。本研究的目的是利用这些反应来制备立方氮化硼或其它陶瓷材料。首先，用ArF准分子激光、Ar离子激光和YAG激光分别照射水和溶解有甲烷、氢气和氧气等气体的水，用分光光度法测定其发光强度。结果表明，ArF准分子激光束能激发水，产生O ~（2+）、OH、H ~（2+）、O ~（2+）等自由基。而其他激光束不能激发一个，但加热固体材料。其次，腔室的大约60体积%填充有水，并且上部填充有甲烷。甲烷溶于水中的压力为350 kPa。腔室上部的气体压力为100 kPa。的 ...更多信息 n ArF准分子激光束聚焦在水面下。因此，薄膜沉积在光束聚焦区域周围的水面上。从透射电镜图像可以看出，Si_3N_4陶瓷中直径约为30 nm的小颗粒相互连接在一起。尽管将陶瓷放置在距离激光束1 mm处，但邻近激光束的陶瓷的颜色发生了变化。如上所述，ArF准分子激光束可以激发水，另一方面，Ar离子激光束不能激发水，而是加热陶瓷材料。用Ar离子激光器分别在水和空气中辐照相同的Si_3N_4陶瓷。在这两种情况下都形成了孔，但是形成的特征彼此不同，并且在水中处理的一个似乎被部分蚀刻。这取决于水和加热的陶瓷之间的水热反应。还期望加工在高温下与水反应的cBN。在水和水蒸气环境中辐照cBN单晶。在这两种情况下，都形成了非常清晰的形状孔。特别是在水蒸气中的一个显示出高结晶度的电子衍射。还观察到孔周围的晶体习性。少

When solid materials are irradiated by laser beam in the presence of water, they are heated to high temperature, further chemical reaction between solid materials and radicals which are produced from water is expected. The aim of this research is to process cubic boron nitride or other ceramic materials by using these reactions.Firstly water and water which dissolving gases, such as methane, hydrogen and oxygen, were irradiated by an ArF excimer laser beam, an Ar ion laser beam and a YAG laser beam and the luminescences were examined by Spectrophotometry. As the results ArF excimer laser beam can excite water and radicals such as O2+, OH, H2, O2 and etc. are produced. While the other laser beams could not excite one but heat the solid materials. Secondly approximately 60 volume percent of a chamber was filled with water and the upper part was filled with methane. The pressure of the methane dissolved in water was 350kPa. The gas pressure of the upper part of the chamber was 100kPa. The … More n ArF excimer laser beam was focused just below the water surface. Consequently, film was deposited on the water around the beam-focus area. From a TEM image, small particles of about 30nm in diameter are connected with each other in the mesh.Thirdly Si3N4 ceramics were immersed in water and ArF excimer laser beam was irradiated. Although the amics were placed 1mm away from the laser beam, the color of ceramics adjacent to the laser beam changed. ArF excimer laser beam can excite water as mentioned above, on the other hand, Ar ion laser beam can not excite water but rather heats the ceramic material. The same Si3N4 ceramics were irradiated by an Ar ion laser in both water and air. On both cases holes are formed, however the formed features are different each other and one processed in water seems to be partly etched. This depends on the hydro-thermal reaction between water and heated ceramics. It is also expected to process cBN which react with water at high temperature. cBN single crystal was irradiated in water and water vapor environments. In both cases very clear shaped holes were formed. In particular one in water vapor showed high crystallinity on electron diffraction. Also crystal habits were observed around the holes. Less