本研究係探討HfNbTaTiZr、HfNbTaTi、HfNbTaZr及HfNbTiZr四種成分高熵合金的表面性質及腐蝕浸出之研究。X光繞射分析結果顯示HfNbTaTiZr、HfNbTaTi、HfNbTaZr及HfNbTiZr高熵合金於室溫下皆屬於BCC晶體結構。X光光電子能譜分析結果顯示Hf、Nb、Ta及Zr元素於表面大部分以HfO2、Nb2O5、Ta2O5及ZrO2氧化態形式存在，僅存在少部分金屬態；而Ti元素於表面觀察到的皆為TiO2氧化態，並無觀察到金屬態存在。電化學測試結果顯示，HfNbTaTiZr、HfNbTaTi、HfNbTaZr及HfNbTiZr高熵合金與316L不鏽鋼有相近的腐蝕電位及腐蝕電流，表示四種成分高熵合金具有與316L不鏽鋼相似的耐腐蝕性質。原子力顯微鏡表面型態分析結果顯示，HfNbTaTiZr、HfNbTaTi、HfNbTaZr及HfNbTiZr高熵合金與316L不鏽鋼經過電化學測試後，表面粗糙度皆有所上升。腐蝕浸出結果顯示，HfNbTaTiZr、HfNbTaTi、HfNbTaZr及HfNbTiZr高熵合金經過60天腐蝕浸出後，Hf及Ta元素釋出量相較Nb及Zr元素高出許多，而Ti元素釋出量則為最低。雖然HfNbTaTiZr、HfNbTaTi、HfNbTaZr及HfNbTiZr高熵合金離子釋出量高出預期，但其組成元素皆具有高度的生物相容性，因此HfNbTaTiZr、HfNbTaTi、HfNbTaZr及HfNbTiZr高熵合金於生醫材料領域發展仍具有相當的應用潛力。

The surface properties and the selectively leaching behaviors of HfNbTaTiZr, HfNbTaTi, HfNbTaZr, and HfNbTiZr high entropy alloys (HEAs) were investigated in this study. X-ray diffraction results showed that HfNbTaTiZr, HfNbTaTi, HfNbTaZr, and HfNbTiZr HEAs all possessed a BCC structure at room temperature. X-ray photoelectron spectroscopy results revealed that most Hf, Nb, Ta, Zr near the surface of these HEAs were in their oxidation states, rather than in their metallic states. The Ti on the surface of these HEAs was mostly in the highly passive TiO2 oxidation state. Electrochemical test results revealed that the HfNbTaTiZr, HfNbTaTi, HfNbTaZr, HfNbTiZr HEAs possessed of similar corrosion properties as 316L stainless steel. Atomic force microscopy results showed that the surface roughness of these HEAs increased after electrochemical test. The selective leaching results showed that the concentrations of Hf and Ta ions released from these HEAs were much higher than those of the Nb and Zr ions. The concentration of Ti released from these HEAs was much lower than the other ions. Although the ions concentrations leaching from HfNbTaTiZr HEAs were higher than our expected, HfNbTaTiZr HEAs still have potential biomedical applications since all their consistent elements are highly biocompatible.

摘要 i
Abstract ii
誌謝 iii
目錄 iv
圖目錄 vi
表目錄 ix
第一章 前言 1
第二章 文獻回顧 3
2.1 生醫材料 3
2.2 生醫金屬材料 3
2.3 高熵合金 (High Entropy Alloy, HEA) 4
2.4 高熵合金於生醫材料的應用 5
2.5 腐蝕 8
第三章 實驗設備與方法 19
3.1 HfNbTaTiZr system高熵合金的設計與熔煉 19
3.2 HfNbTaTiZr system高熵合金晶體結構分析 19
3.3 HfNbTaTiZr system高熵合金表面化學組成分析 19
3.4 HfNbTaTiZr system高熵合金電化學分析 20
3.5 HfNbTaTiZr system高熵合金表面型態分析 20
3.6 HfNbTaTiZr system高熵合金之腐蝕浸出 21
第四章 結果與討論 27
4.1 HfNbTaTiZr system高熵合金X光繞射結果分析 27
4.2 HfNbTaTiZr system高熵合金X光光電子能譜儀(XPS)結果分析 28
4.3 HfNbTaTiZr system高熵合金電化學Tafel極化曲線結果分析 31
4.4 HfNbTaTiZr system高熵合金AFM表面型態分析 32
4.5 HfNbTaTiZr system高熵合金腐蝕浸出行為 33
4.6 HfNbTaTiZr system高熵合金腐蝕浸出綜合討論 34
第五章 結論 51
參考文獻 52

[1]Mengdi Zhang, Lijun Zhang, Jiantao Fan, Gong Li, Peter K. Liaw, Riping Liu. Microstructure and enhanced mechanical behavior of the Al7Co24Cr21Fe24Ni24 high-entropy alloy system by tuning the Cr content, Mater. Sci. Eng. A, 733 (2018), pp. 299-306.
[2]Peng Cui, Yimo Ma, Lijun Zhang, Mengdi Zhang, Jiantao Fan, Wanqing Dong, Pengfei Yu, Gong Li, Riping Liu. Effect of Ti on microstructure and mechanical properties of high entropy alloys based on CoFeMnNi system, Mater. Sci. Eng. A, 737 (2018), pp. 198-204.
[3]Shao-Ping Wang, Jian Xu. TiZrNbTaMo high-entropy alloy designed for orthopedic implants As-cast microstructure and mechanical properties, Mater Sci. Eng. C, 73 (2017), pp. 80-89.
[4]Mitsuharu Todai, Takeshi Nagase, Takao Hori, Aira Matsugaki, Aiko Sekita, Takayoshi Nakano. Novel TiNbTaZrMo high-entropy alloys for metallic biomaterials, Scr. Mater., 129 (2017), pp. 65-68.
[5]Takeshi Nagase, Mitsuharu Todai, Takao Hori, Takayoshi Nakano. Microstructure of equiatomic and non-equiatomic Ti-Nb-Ta-Zr-Mo high-entropy alloys for metallic biomaterials, J. Alloys Compd., 753 (2018), pp. 412-421.
[6]Takao Hori, Takeshi Nagase, Mitsuharu Todai, Aira Matsugaki, Takayoshi Nakano. Development of non-equiatomic Ti-Nb-Ta-Zr-Mo high-entropy alloys for metallic biomaterials, Scr. Mater., 172 (2019), pp. 83-87.
[7]Takeshi Nagase, Yuuka Iijima, Aira Matsugaki, Kei Ameyama, Takayoshi Nakano. Design and fabrication of Ti-Zr-Hf-Cr-Mo and Ti-Zr-Hf-Co-Cr-Mo high-entropy alloys as metallic biomaterials, Mater. Sci. Eng. C, 107 (2020), 110322.
[8]Ryan newell, Zi Wang, Isabel Arias, Abhishek Mehta, Yongho Sohn, Stephen Florczyk. Direct-Contact Cytotoxicity Evaluation of CoCrFeNi-Based Multi-Principal Element Alloys, J. Funct. Biomater., 9 (4) (2018), pp. 59.
[9]Yuan Yuan, Yuan Wu, Zhi Yang, Xue Liang, Zhifeng Lei, Hailong Huang, Hui Wang, Xiaogjun Liu, Ke An, Wei Wu, Zhaoping Lu. Formation, structure and properties of biocompatible TiZrHfNbTa high-entropy alloys, Mater. Res. Lett., 7 (2018), pp. 225-231.
[10]A. Motallebzadeh, M. B. Yagci, E. Bedir, C. B. Aksoy, D. Canadinc. Mechanical Properties of TiTaHfNbZr High-Entropy Alloy Coatings Deposited on NiTi Shape Memory Alloy Substrates. Mater. Trans. A, 49 (2018), pp. 1992-1997.
[11]C. B. Aksoy, D. Canadinc, M. B. Yagci. Assessment of Ni ion release from TiTaHfNbZr high entropy alloy coated NiTi shape memory substrates in artificial saliva and gastric fluid. Mater. Chem. Phys., 236 (2019) 121802.
[12]Amir Motallebzadeh, Naeimeh Sadat Peighambardoust, Saad Sheikh, Hideyuki Murakami, Sheng Guo, Demircan Canadinc. Microstructural, mechanical and electrochemical characterization of TiZrTaHfNb and Ti1.5ZrTa0.5Hf0.5Nb0.5 refractory high-entropy alloys for biomedical applications. Intermetallics, 113 (2019) 106572.
[13]S. H. Chang, S. K. Wu, B. S. Liao, C. H. Su. Selectively leaching and surface properties of CoNiCr-based medium-/high-entropy alloys. Appl. Surf. Sci., 515 (2020) 146044.
[14]Nitesh R. Patel, Piyush P. Gohil. A Review on Biomaterials: Scope, Applications & Human Anatomy Significance, Int. J. Emerg. Technol. Adv. Eng., 2 (4) (2012), pp. 91-101.
[15]Mahmoud Z. Ibrahim, Ahmed A.D. Sarhan, Farazila Yusuf, M. Hamdi. Biomedical materials and techniques to improve the tribological, mechanical and biomedical properties of orthopedic implants-A review article. J. Alloys Compd., 714 (2017), pp. 636-667.
[16]I Gurappa. Characterization of different materials for corrosion resistance under simulated body fluid conditions. Mater Charact, 49 (1) (2002), pp. 73-79.
[17]D.D. Xiang, P. Wang, X.P. Tan, S. Chandra, C. Wang, M.L.S. Nai, S.B. Tor, W.Q. Liu, E. Liu. Anisotropic microstructure and mechanical properties of additively manufactured Co-Cr-Mo alloy using selective electron beam melting for orthopedic implants. Mater. Sci. Eng. A, 765 (2019), 138270.
[18]M. Geetha, A.K. Singh, R. Asokamani, A.K. Gogia. Ti based biomaterials, the ultimate choice for orthopaedic implants – A review. Prog. Mater. Sci., 54 (2009), pp. 397-425.
[19]W.J. Buehler, J.V. Gilfrich, R.C. Wiley. Effect of Low-Temperature Phase Changes on the Mechanical Properties of Alloys near Composition TiNi. J. Appl. Phys., 34 (1963), pp. 1475.
[20]D.Y. Li. Exploration of TiNi shape memory alloy for potential application in a new area: tribological engineering. Smart Mater Struct, 9 (5) (2000).
[21]Wei-huai GONG, Yu-hua CHEN, Li-ming KE. Microstructure and properties of laser micro welded joint of TiNi shape memory alloy. Transactions of Nonferrous Metals Society of China, 21 (9) (2011), pp. 2044-2048.
[22]B. Cantor, I.T.H. Chang, P. Knight, A.J.B. Vincent. Microstructural development in equiatomic multicomponent alloys. Mater. Sci. Eng. A, 375-377 (2004), pp. 213-218.
[23]T.K. Chen, T.T. Shun, J.W. Yeh, M.S. Wong. Nanostructred nitride films of multi-element high-entropy alloys by reactive DC sputtering. Surf. Coat. Technol., 188-189 (2004), pp. 193-200.
[24]J.W. Yeh, S.K. Chen, S.J. Lin, J.Y. Gan, T.S. Chin, T.T. Shun, C.H. Tsau, S.Y. Chang. Nanostructred high-entropy alloys with multiple principal elements: novel alloy design concepts and outcomes. Adv. Eng. Mater., 6 (5) (2004), pp. 299-303.
[25]Jien-Wei Yeh, Su-Jien Lin, Tsung-Shune Chin, Jon-Yiew Gan, Swe-Kai Chen, Tao-Tsung Shun, Chung-Huei Tsau, Shou-Yi Chou. Formation of simple crystal structures in Cu-Co-Ni-Cr-Al-Fe-Ti-V alloys with multiprincipal metallic elements. Metall. Mater. Trans. A, 35 (8) (2004), pp. 2533-2536.
[26]P.K. Huang, J.W. Yeh, T.T. Shun, S.K. Chen. Multi-principal-element alloys with improved oxidation and wear resistance for thermal spray coating. Adv. Eng. Mater., 6 (2004), pp. 74-78.
[27]Chin-You Hsu, Jien-Wei Yeh, Swe-Kai Chen, Tao-Tsung Shun. Wear resistance and high-temperature compression strength of Fcc CuCoNiCrAl0.5Fe alloy with boron addition. Metall. Mater. Trans. A, 35 (2004), pp. 1465-1469.
[28]Ming-Hung Tsai, Jien-Wei Yeh. High-Entropy Alloys: A Critical Review. Mater. Res. Lett., 2 (3) (2014), pp. 107-123.
[29]O.N. Senkov, J.M. Scott, S.V. Senkova, D.B. Miracle, C.F. Woodward. Microstructure and room temperature properties of a high-entropy TaNbHfZrTi alloy. J. Alloys Compd., 509 (20) (2011), pp. 6043-6048.
[30]Guo Sheng Huang, Xiang Bo Li, Lu Kuo Xing. Corrosion behavior of low pressure cold sprayed Zn-Ni composite coatings. Anti-Corrosion Methods and Materials, 63 (6) (2016), pp.461-469.
[31]Mohammed A. Amin, Nader El-Bagoury, Murat Saracoglu, Mohamed Ramadan. Electrochemical and Corrosion Behavior of cast Re-containing Inconel 718 Alloys in Sulphuric Acid Solutions and the Effect of Cl. Int. J. Electrochem. Sci., 9 (2014), pp. 5352-5374.
[32]William Stephen Tait. An Introduction to Electrochemical Corrosion Testing for Practicing Engineers and Scientists. (1994).
[33]Denny A. Jones. Principles and Prevention of Corrosion. (1996).
[34]N.K. Das, J. Chakrabartty, S.F.U. Farhad, A.K. Sen Gupta, E.M.K. Ikball Ahamed, K.S. Rahman, A. Wafi, A.A. Alkahtani, M.A. Martin, N. Amin. Effect of substrate temperature on the properties of RF sputtered CdS thin films for solar cell applications, Results Phys, 17 (2020), 103132.
[35]Jiří Zýka, Jaroslav Málek, Jaroslav Veselý, František Lukáč, Jakub Čížek, Jan Kuriplach and Oksana Melikhova. Microstructure and Room Temperature Mechanical Properties of Different 3 and 4 Element Medium Entropy Alloys from HfNbTaTiZr System, Entropy, 21(2) (2019), 114.
[36]S.Y. Chen, Y. Tong, K.K. Tseng, J.W. Yeh, J.D. Poplawsky, J.G. Wen, M.C. Gao, G. Kim, W. Chen, Y. Ren, R. Feng, W.D. Li, P.K. Liaw. Phase transformation of HfNbTaTiZr high-entropy alloy at intermediate temperature. Scr. Mater, 158 (2019), pp. 50-56.
[37]J. Rituerto Sin, A. Neville, N. Emami. Corrosion and tribocorrosion of hafnium in simulated body fluids. J. Biomed Mater Res Part B Appl. Biomater., 102 (6) (2014), pp. 1157-1164.