| Title |
The Effects of S and Ir on the Microstructure of Ag - Pd Dental Casting Alloys |
| Authors |
신승렬(Seung Ryoul Shin),서용찬(Yong Chan Suh),이진형(Zin Hyoung Lee) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Abstract |
The effects of S and Ir on the microstructures of binary Ag-25%Pd alloy and a commercial alloy, A-2 (Ag-25 wt%Pd-2 wt%Au-2 wt%In-0.84 wt%Zn-0.5 wt%Ir) were studied. The segregation tendency of S in the grain boundary was investigated by Auger electron spectroscopy (AES) and Energy Dispersive Spectroscopy (EDS) with varying S concentrations. The effect of the cooling rate on the microstructures and segregation was also investigated. The compositions of several positions on the fractured surface were measured by EDS analysis. The grain refining effect of Ir was obvious when the concentration of Ir was more than 0.1%. At S-concentrations above 0.1%, Ag₂Pd₃S phase was observed at the dendrite and grain boundary due to S-segregation during solidification. This phase did not appear at 0.01% S, but the S-concentration at the grain boundary was much higher than the bulk concentration, showing S-segregation to the grain boundary. The degree of S-segregation to the grain boundary decreased slightly with grain refining. The segregation of In and Zn in A-2 alloy containing high S concentration did not occur while it occurred in the alloy with low S concentration. |