표제지
목차
I. 서론 4
II. 실험재료 및 방법 4
1. 실험재료 4
a. 내변색시편의 제작 5
b. 내부식시편 의 제작 5
c. 인장시편의 제작 5
d. 경도시편 및 금속조직시편, X-선 회절시편, EPMA분석시편 제작 6
2. 실험방법 6
a. 내변색성 시험방법 6
b. 내부식성 시험방법 6
c. 기계적 성질 시험방법 6
III. 실험성적 7
1. 내변색성시험성적 7
2. 내부식성시험성적 7
3. 기계적 성질시험성적 7
IV. 총괄 및 고찰 10
1.내변색성에 미치는 영향 10
2.내부식성에 미치는 영향 11
3.기계적성질에 미치는 합금원소의 영향 12
V. 결론 15
참고문헌 15
ABSTRACT 17
Table 1. Composition of alloys studied.(%) 5
Table 2. Tarnishing scoring sytem by Hodges. 6
Table 3. The results do the tarnish ing test. 7
Table 4. Standard electrode potentials for various metals at 25℃. 11
Table 5. The results of X-ray diffraction of Ag-25Pd2.dZn-2.5In system. 13
Table 6. Results of electron probe micro analysis of Ag-25Pd-2.5Zn-In system.(%) 15
Fig. 1. Corrosion test equipment and specimens. 5
Fig. 2. Gettleman and Harrisom type sub size tensile test speciment (a) and spilt metal die for wax pattern(b). 6
Fig. 3. Micrographs of tarnished surfaces of various alloys. After 3 days of immersion in 0.1% Na₂S solution at 37℃.(이미지참조) 8
Fig. 4. Forward scan potentiodynamic polarization curves of various alloys. Alloy 1. 75Ag- 25Pd Alloy 2. 70Ag-25Pd-4In-1Zn Alloy 3. 70Ag-25Pd-2.5In-2.5Zn Alloy 4.70Ag-25Pd-1In-4Zn 9
Fig. 5. The effect of alloying elements on the peak current density of as cast specimens. As the content of In is increased. The Peak current density is decreased. 9
Fig. 6. The effect of In content on the hadness of various states of Ag-25Pd-1Zn-xIn system. The hardness ofas cast specimen is also higher thhan that of the aged one. As In content is increased, the hardness is more sharply increased. In can be effective strengthener of th system 9
Fig. 7. The effect on In content on the tensile strength of Ag-25Pd-1Zn-xIn system. Tensile strength and hardness have similar behavior in this system. 9
Fig. 8. The combined effect of In and Zn on the hardness of various states of Ag-25Pd-xZn-yIn system. The hardness of aged specimen of Ag-25Pd-2.5Zn-2.5In is higher than of the cast state. 10
Fig. 9. The effect of aging temperature on the hardness of Ag-25Pd-2.5Zn-2.5In.(Aging time is 30min.) As temperature is increased, the hardness is also increased. The phenomena is due to the precipitation hardening of this system. 10
Fig. 10. The effect of aging time on the hardness of Ag-25Pd-2.5Zn-2.5In. (Aging temperature is 450℃.) As the aging time is increased, the hardness is increased with the time. 10
Fig. 11. X-ray diffranction charts of various states of Ag-25Pd-2.5Zn-2.5In system. 12
Fig. 12. Micrographs of various states of Ag-25Pd-2.5In-2.5Zn system. 14
Fig. 13. Electon probe micro analysis site 14