Al0.3CrFe1.5MnNiy高熵合金之腐蝕行為研究

The Investigation of the Corrosion Properties of Al0.3CrFe1.5MnNiy High Entropy Alloys

本實驗主要是探討高熵合金Al0.3CrFe1.5MnNiy的腐蝕行為，此高熵合金中的Al元素其用途主要是加強機械性質，但抗腐蝕能力不佳，因此考慮在少量Al成分的情況下，改變Ni的成分比例，並與304不銹鋼做比較；從極化掃描、電化學阻抗頻譜、循環極化及掃描式電子顯微鏡的結果顯示：在0.5 M除氣硫酸溶液中，當Ni的成分比例從0.5增加到1.5份時，確實其抗腐蝕能力增加，且與304不銹鋼相當，但Ni若添加太多，反而沒有得到更佳的抗蝕效果；而在含氯離子的硫酸溶液中，Ni含量高的試片表面仍會出現許多緻密的孔洞，因此可知其抗孔蝕能力並沒有得到改善，此應與合金中Al成分之存在有所關聯。

High entropy alloys (HEAs) are kinds of multi-component glassy alloys composed of several major alloying elements, such as copper, nickel, aluminum, cobalt, chromium, iron, titanium, etc. It is known that HEA contained more aluminum component, evaluated previously, is less resistant to general corrosion than type 304 stainless steel (304SS), both in H2SO4 and in NaCl solutions at room temperature. In this experiment shows that the increasing of alloying nickel component in Al0.3CrFe1.5MnNi0.5 alloy will increase the corrosion resistance in 0.5 M H2SO4 at ambient temperature (~ 22 ℃) and is similar to that of 304SS. On the other hand, the HEA's resistance to pitting corrosion in deaerated H2SO4 solution containing Cl- is inferior to that of 304SS, as indicated by a lower pitting potential and a narrower passive region for the HEA. The positive loop of hysteresis in cyclic polarization tests also confirmed that the HEA is susceptible to pitting corrosion in chloride-containing 0.5M H2SO4 solution.