| Summary: | 碩士 === 義守大學 === 材料科學與工程學系碩士班 === 97 === This study is focusing on the variation of microstructure and antibacterial property in austenitic stainless steels with different silver contents (0.1wt.%, 0.2wt.% and 0.3wt.%).This study can be divided into four parts: (1) influence of hardness on austenitic stainless steels with Ag-adding. (2) variation of microstructure on austenitic stainless steels with Ag-adding after solution treatment. (3) influence of antibacterial properties on austenitic stainless steels with Ag-adding. (4) influence of corrosion resistance on austenitic stainless steels with Ag-adding.The test result shows that the hardness is decreased slightly with Ag content increasing. The average hardness value is about HRB 80 ± 2. It shows that Ag-Adding is not the major factor to enhance the hardness of AISI 304 and AISI 316L stainless steels. The microstructure of AISI 304 and AISI 316L austenitic stainless steels is composed of γ-austenite and δ-ferrite phases, which indentified by OM and FE-SEM. The result demonstrates that the adding of Ag element doesn’t influence the microstructure of AISI 304 and AISI 316L austenitic stainless steels.For antibacterial property, AISI 304 and AISI 316L stainless steels reach to 99.99% of the cell reduction rate to Esherichia coli with Ag-adding. In addition, the cell reduction rate is 78.3%, while AISI 304 stainless steel possesses 0.3 wt. % Ag, and AISI 316L stainless steel has over 99% of cell reduction rate to Staphylococcus with adding 0.2wt% Ag.In the corrosion resistance test, the result of dynamic polarization curve shows that the Ecorr. value is increased with silver content increasing. AISI 304 possesses the superior corrosion resistance while silver content is added to 0.1wt%, the Ecorr. and Enp. value are -0.709 V and 0.01V, respectively. As AISI 316L stainless steel, it has no variation of corrosion resistance with Ag-adding.
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