Nano SiC Particles In-situ Growth And Fabrication Of Nano SiC Coatings Via Laser Irradiation

SiC nano-whisker is nanometer sized one-dimensional single crystalline. The SiC nano-whiskers film is provided with high strength and high hardness, and they are widely used as reinforcing materials for the fabrication of ceramic and metal matrix coatings. The growth mechanism of the SiC particles via laser irradiation was studied in this dissertation. As the precursor, the sintering characteristic of SiC particles heated by laser source was also discussed. The main works accomplished and conclusions are presented as follows: 1. The sintering and growth process via laser irradiation was studied, the materials transformation mechanism was analyzed, and the mathematic model of grain size growing of nano particle material via laser irradiation was built. The growth trends of grain size were simulated under different laser technological parameters. 2. Experimental researches on the laser irradiation of nano SiC material were carried out. The microstructures of the sample gotten by laser irradiation were studied in detail with X-ray diffraction, scanning electron microscopy. The varying of phase and microstructure in the temperature field of laser beam was researched; the nano-ceramics fabrication technology via laser beam rectangle spot was put forward and analyzed briefly. The rapid sintering for nano-structured material can be realized with the suitable parameters of laser beam. 3. The SiC nano-whiskers were obtained via laser irradiation, the phase structure of it is the typical cubic. The effect of the temperature field and heating time on the morphology of SiC nano-whiskers were discussed. 4. SiC structural coatings were made via laser irradiation on different substrates including nano-SiC composite coatings, nano-SiC coatings and nano-SiC coatings with the networked SiC nano-whiskers. The suitable laser technological parameters were gotten.