黃坤祥2006-07-252018-06-282006-07-252018-06-282005http://ntur.lib.ntu.edu.tw//handle/246246/12492The carbon-sulfur analyzer has been purchased and installed. The methodology of measuring the carbon soot and the dissolved carbon are being developed. The preliminary tests show that this instrument can be used to identify the amount of carbon soot, the dissolved carbon, and the total carbon content. The remaining issues are the development on calibration and how to improve the accuracy. This fine tuning technique will be completed before the end of the first year of the project. While the instrument was being purchased and installed, the efforts of the study were focused on the effect of alloying element on dissolved carbon and the mechanical properties. The key finding is that nickel, which is one of the most popular alloying elements in powder metal compacts, has a strong repelling effect on carbon. As homogenization proceeded, nickel was distributed on the iron powder surface at the early stage through surface diffusion. This, however, forced carbon to move toward the center region of the powder. Thus, the powder surfaces were enriched in nickel while lean in carbon. These nickel-rich and carbon-lean areas, which were soft, were also present on the surface of the powder and pores. The electron backscattering diffraction (EBSD) technique was employed to identify the structure of these areas and the results show that these areas were ferrites, not the austenite, as was frequently speculated.application/pdf1370315 bytesapplication/pdfzh-TW國立臺灣大學材料科學與工程學系暨研究所EBSDCARBON ANALYSISCARBON SOOTNICKELHOMOGENIZATIONreporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/12492/1/932216E002018.pdf