| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 89 === Abstract
Effect of fluxing chemicals on the quality of the aluminum castings were fully assessed and discussed in this study. Six different fluxing chemicals classified into three groups(fluorides, chlorides and carbonates) were added to A356.2, Al-Si and Al-Cu melts respectively.
The quality of aluminum castings was evaluated by the oxide particles and oxide films on polished surface of aluminum chill samples (after ultrasonic vibration treatment). The inclusion particles and oxide films (termed as foggy area of polished surface from aluminum chill samples) were statistically assessed by pc-meter image process system. Alloying elements on the quality of aluminum castings were commonly different while it was strongly dominated by the fluxing chemicals.
Experimental results showed that the morphologies of foggy areas (or porosity) on the aluminum chill samples were mainly controlled by the orders of fluorides, chlorides and carbonates. The average of inclusion particles was 156, 145 and 132 (counts/mm2) through the image process system after fluxing with fluorides, chlorides and carbonates in each melts, respectively.
The skimmed slag was also observed and detected after fluxing treatment. The dry-type dross was found in fluxing melts with fluorides when the others were wet-type fluxed by the chlorides and carbonates. Many spontaneously reactive and complex compounds were detected by the X-ray powder diffraction spectroscopy.
Eventually, the optimal fluxing process was achieved through the mechanical properties testing of fluxed specimens.
Keyword: fluorides, chlorides, carbonates, fluxing treatment, inclusion particles, oxide films, dry-type slag, wet-type slag
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