The Electrochemical Pitting Behavior Studies of the A1xCo1.5CrFeNi1.5Ti0.5Moy High Entropy Alloys

• Main Authors: Ho, Zong-han, 何宗翰
• Other Authors: H.C. Shih
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/53713716620218853646

碩士 === 中國文化大學 === 材料科學與奈米科技研究所 === 99 === This study is mainly focused on the electrochemical pitting corrosion behavior of the newly developed high entropy alloy. In the experiment, the roles played by Al and Mo in the Al0.1Co1.5CrFeNi1.5Ti0.5Mo0.1high entropy alloy on the electrochemistry were evaluated and compared with type 304 stainless steel. The result shows that high entropy Al0.1-Mo0.1 has a better corrosion resistance than type 304 stainless steel in 0.1M NaCl solution. Other salt like NH4Clwas also used and the result indicated that high entropy alloy has a less pitting corrosion resistance, the higher the salt concentration, the less the pitting resistance. In this respect, the alloys with varying Al and Mo can be arranged in the following order starting with the highest pitting corrosion resistance : Al0.1-Mo0.2>Al0.1-Mo0.1>Al0.2-Mo0.1.The critical pitting temperature (CPT) of the Al0.1-Mo0.1 in NH4Cl solution decreases as the NH4Cl concentration increases. The corrosion potential (Ecorr) has been less affected by the chloride (Cl-) concentration, but significantly affected by the type of chloride salts as well as the alloying composition of the sample alloy. The result of SEM indicated a dendritic structure of the alloy to start with and the actual corrosion took place at the interdendritic regions. Once the CPT being surpassed, the pitting situation of the high entropy alloy tends to be serious.