脫脂殘留碳之形態及其對乾壓與射出成形工件機械性質之影響(1/2)
Date Issued
2005
Date
2005
Author(s)
黃坤祥
DOI
932216E002018
Abstract
The 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.
Subjects
EBSD
CARBON ANALYSIS
CARBON SOOT
NICKEL
HOMOGENIZATION
Publisher
臺北市：國立臺灣大學材料科學與工程學系暨研究所
Type
report
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