本論文是改變CoCrFeNiTax高熵合金中Ta元素的含量，設計出三種不同比例組成的合金，分別為CoCrFeNiTa0.1、CoCrFeNiTa0.3、CoCrFeNiTa0.5，研究三種不同Ta含量的高熵合金微結構及電化學性質，此實驗用恆電流/恆電位儀測CoCrFeNiTa0.1、CoCrFeNiTa0.3、CoCrFeNiTa0.5合金在除氧環境下分別使用1M硫酸、1M鹽酸、1M硝酸及1M氯化鈉溶液，再分別用攝氏30oC、40 oC、50 oC、60 oC、測量出來的極化曲線來量測腐蝕電位、腐蝕電流、鈍態區間電位，再用三種合金與304不鏽鋼互相做比較，除氧環境下的四種溶液中三種合金因為溫度以及溶液的不同，所以腐蝕後的狀況也不盡相同。研究中觀察這些合金在不同溶液中的鈍態區、腐蝕電位Ecorr和腐蝕電流icorr，可以了解此系列合金的腐蝕性質。此三種合金也與304不鏽鋼做比較，結果顯示三種合金的電化學性質在這四種溶液中皆優於304不鏽鋼。做SEM/EDS分析時可以發現腐蝕情況。三種合金也有FCC加HCP共晶結構的出現。三種合金做X-ray繞射分析，結果顯示若只有CoCrFeNi時，只會有FCC基地相，當加入Ta後會形成FCC基地相及HCP基地內的小顆粒相的混合立方結構相。三種合金也做硬度測試，顯示Ta添加含量越高，硬度會越大，皆可從本論文得知。
This study investigated the effects of Ta-content on the microstructures, hardness and corrosion properties of CrFeCoNiTax alloys. The results indicated that adding of Ta-content would change the microstructures from single-phase (FCC) of CrFeCoNi alloy to dual-phase (FCC+HCP) of CrFeCoNiTax alloys; also increased the hardness of these CrFeCoNiTax alloys. This study used constant galvanostatic/ potentiometric to measure the polarization curves of CoCrFeNiTa0.1、CoCrFeNiTa0.3、CoCrFeNiTa0.5 alloys in the deaeration 1M sulfuric acid, 1M hydrochloric acid, 1M nitric acid and 1M sodium chloride solutions; the tested temperatures were fixed at 30°C, 40°C, 50°C, 60°C. The results of the CrFeCoNiTax alloys were also compared with commercial 304 stainless steel. The results indicated that the corrosion properties of these CrFeCoNiTax alloys were all better than that of commercial 304 stainless steel.
