Tham khảo tài liệu 'properties and applications of silicon carbide part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 382 Properties and Applications of Silicon Carbide influence when the milling is performed with smaller balls. Whereas for vial filling volume depending on the ball size a local minimum in filling parameter was found. Table 14 reports Vickers hardness of different Al SiC composites prepared by MA. Al SiC composition Technique Vickers hardness Hv Reference Al-20 vol. SiC Al nanoSiC Sintered at 600 C for 1h 40 Chaira et al 2007 Al SiC composite SiC incorporated by mechanically stirring the fully molten Al 36 2 - 39 1 Tham et al 2001 Al-1 vol. nano SiC Al nanaoSiC hot pressed 163 Kolloa et all 2010 Table 14. Microhardness of different Al SiC composites obtained by MA. Chaira et al 2007 demonstrated that with increasing sintering temperature the hardness of Al-SiC composites increased too due to good compatibility of Al and SiC particles. However the hardness values of the obtained composite remained by far lower than the one given by Kolloa et all 2010 who had studied and optimized the milling s parameters on the hardness of the material. Moreover a better density was also achieved a property which is also related to the hardness of the material. 5. Conclusion Silicon carbide can occur in more than 250 crystalline forms called polytypes. The most common ones are 3C 4H 6H and 15R. Silicon carbide has attracted much attention a few decades ago because it has a good match of chemical mechanical and thermal properties that makes it a semiconductor of choice for harsh environment applications. These applications include high radiation exposure operation in high temperature and corrosive media. To obtain high-performance SiC ceramics fine powder with narrow particles-size distribution as well as high purity are required. For this purpose many effective methods have been developed. The simplest manufacturing process of SiC is to combine silica sand and carbon in an Acheson graphite electric resistance furnace at temperatures higher than 2500 C. The poor quality of the .
