純銅加鎳能明顯地提高強度、耐蝕性和熱電性，並降低電阻溫度係數(Temperature Coefficient of Resistance, TCR)，由於銅鎳合金具有優異的抗腐蝕能力，被廣泛的應用於各工程中的耐蝕件。銅鎳合金系統中，當銅鎳的比例接近1時，經由退火熱處理使其結晶性更好，而有最低的電阻溫度係數，使其近幾年被積極地作為薄膜電阻元件的材料。
傳統的合金製備需在極高溫的環境下，將金屬熔煉混合，此生產成本非常高。目前低TCR性質的銅鎳合金是利用濺鍍或配膏印刷的方式製成。本研究是配製含有不同銅鎳比例的溶液，利用定電壓電鍍的方式，在基材上共沉積不同比例的銅鎳鍍膜，最後以退火的方式使銅原子與鎳原子在晶格中移動，形成結晶性較好的銅鎳合金相，以期達到降低生產成本的目的。
從研究中可以發現，當定電壓為-0.9 V (vs. Ag/AgCl)時，溶液銅鎳比例97:3其鍍層有最接近1之銅鎳比，電鍍3小時後，鍍層厚度約為10 μm，電阻值約為150 mΩ；而當定電壓為-1.3 V (vs. Ag/AgCl)時，則是溶液銅鎳比例90:10其鍍層有最接近1之銅鎳比，電鍍20分鐘後，亦可達到與前者相近的厚度、電阻值；兩者試片經退火熱處理後，從各分析觀察到銅鎳合金相微結構的改變，電阻值皆上升，而TCR則有顯著的下降。

Adding nickel (Ni) atoms intentionally into the pure copper (Cu) atoms can obviously increase the performance in strength, corrosion, and thermoelectricity. Moreover, it can also reduce the temperature coefficient of resistance (TCR). Cu-Ni alloys are applied widely as the anti-corrosive structure in engineering. When the atomic percent of Cu to Ni is around 1 in the Cu-Ni alloys system, it has good crystallinity through annealing leading to the low TCR. It has been applied as the material of resistive components in recent years.
Traditional method in preparing alloys is in extremely high temperature condition for melting and mixing the metals, which costs very expensive. So far, the copper-nickel alloys with low TCR are fabricated by sputtering or paste printing. In this research, we co-deposit Cu and Ni film in the solutions containing different composition ratio of Cu to Ni on the substrate, the sintered aluminum (Al) paste, at the constant voltage. After annealing, Cu atoms and Ni atoms migrate in the crystal lattice to form phase of Cu-Ni alloys. By this method, we can reduce the cost to fabricate alloys.
The results in this study showed that when we co-deposit Cu and Ni layer at -0.9 V (vs. Ag/AgCl) in the solution with the composition ratio of Ni to Cu as 97:3, the atomic percentage of Cu to Ni is approximately around 1 in the Cu-Ni alloys system. Electroplated for 3 hours, the thickness of the layer is growing up around 10 μm, and the resistance is around 150 mΩ. On the other hand, while co-depositing Cu and Ni layer at -1.3 V (vs. Ag/AgCl) on the substrate for 20 minutes, we can obtain the same results as the former in the solution with the composition ratio of Cu to Ni as 10:90. Later, after annealing both samples, we observe the change of microstructure in Cu-Ni alloys by analysis. Furthermore, there is an increase in the resistance but a dramatic reduction in TCR.

[1] Hongyan Wu, Yi Wang, Qingdong Zhong, Minqi Sheng, and Hailong Du, “The semi-conductor property and corrosion resistance of passive film on electroplated Ni and Cu-Ni alloys,” Journal of Electroanalytical Chemistry, Vol. 663, pp. 59-66, 2011.
[2] Aïda Varea, Eva Pellicer, Salvador Pané, Bradley J. Nelson, Santiago Suriñach, Maria Dolors Baró, and Jordi Sort, “Mechanical Properties and Corrosion Behaviour of Nanostructured Cu-rich CuNi Electrodeposited Films,” International Journal of Electrochemical Science, Vol. 7, pp. 1288-1302, 2012
[3] Waheed A. Badawya, Khaled M. Ismail, and Ahlam M. Fathi, “Effect of Ni Content on the Corrosion Behavior of Cu-Ni Alloys in Neutral Chloride Solutions,” Electrochimica Acta, Vol. 50, pp. 3603-3608, 2005
[4] Veena Subramanian, P. Chandramohan, M.P. Srinivasan, S. Velmurugan and S.V. Narasimhan, “Corrosion of Cupronickel Alloy in Permanganate under Acidic Condition,” Corrosion Science, Vol. 49, pp. 620-636, 2007
[5] “Copper-Nickel Alloys: Properties, Processing, Applications,” Available from: https://www.copper.org/applications/marine/cuni/properties/DKI_booklet.html, [cited 06, May, 2018],
[6] William D. Callister, and David G. Rethwisch, “Applications and Processing of Metal Alloys” in Materials Science and Engineering, 8th edition, John Wiley & Sons, Asia, pp. 406-416, 2011
[7] Nurul Khalidah Yusop, Nurulakmal Mohd Shariff, See Chin Chow, and Ahmad Badri Ismail, “Structural and Electrical Characterizations of CuNi Thin Film Resistors,” Procedia Chemistry, Vol. 19, pp. 619-625, 2016
[8] Masami Ishikawa, Hidehiko Enomoto, Naohiro Mikamoto, Tsuneshi Nakamura, Masao Matsuoka, and Chiaki Iwakura, “Preparation of Thin Film Resistors with Low Resistivity and Low TCR by Heat Treatment of Multilayered Cu/Ni Deposits,” Surface and Coatings Technology, Vol. 110, pp. 121-128, 1998
[9] Sung-Gi Hur, Dong-Jin Kim, Byoung-Don Kang, and Soon-Gil Yoon, “The Structural and Electrical Properties of CuNi Thin-Film Resistors Grown on AlN Substrates for P-Type Attenuator Application,” Journal of The Electrochemical Society, Vol. 152, pp. G472-G476, 2005
[10] Jae min lee, Sung Ho Lee, Young Jun Kim, and Jong Soo Ko, “Effect of the Diffusion Rate of the Copper Ions on the Co-electrodeposition of Copper and Nickel,” International Journal of Precision Engineering and Manufacturing, Vol.14, pp. 2009-2014, 2013
[11] Pengoeng Grimshaw, Joseph M. Calo, and G. Hradi, “Co-electrodeposition/Removal of Copper and Nickel in a Spouted Electrochemical Reactor,” Industrial & Eingineering Chemistry Reaserch, Vol. 50, pp.9532-9538, 2011
[12] Ramona Y. Ying, “Electrodeposition of Copper-Nickel Alloys from Citrate Solutions on a Rotating Disk Electrode,” Journal of Electrochemical Society, Vol. 135, pp. 2957-2964, 1988
[13] William D. Callister, and David G. Rethwisch, “Imperfections in Solids” in Materials Science and Engineering, 8th edition, John Wiley & Sons, Asia, pp. 93-95, 2011
[14] Reza Abbaschian, Lara Abbaschian, and R.E. Reed-Hill, “Solid Solutions” in Physical Metallurgy Principles, 4th edition, Cengage Learning, USA, pp. 261-267, 2010
[15] William D. Callister, and David G. Rethwisch, “Phase Diagrams” in Materials Science and Engineering, 8th edition, John Wiley & Sons, Asia, pp. 287-298, 2011
[16] Milan Paunovic, and M. Schlesinger, Fundamentals of Electrochemical Deposition, 2nd edition, Wiley-VCH, New York, 2006.
[17] 胡啟章, “電化學反應系統簡介,” in 電化學原理與方法, 五南圖書出版股份有限公司, 台灣, pp. 4-19, 2002
[18] 胡啟章, “參考電極,” in 電化學原理與方法, 五南圖書出版股份有限公司, 台灣, pp. 30-35, 2002
[19] Evgeni B. Budevski, G.T. Staikov, and W.J. Lorenz, Electrochemical Phase Formation and Growth: An Introduction to the Initial Stages of Metal Deposition, Wiley-VCH, New York, 2008
[20] Gosser, and David K., Cyclic Voltammetry: Simulation and Analysis of Reaction Mechanisms, Wiley-VCH, New York, 1993.
[21] 胡啟章, “循環伏安法,” in 電化學原理與方法, 五南圖書出版股份有限公司, 台灣, pp. 105-109, 2002
[22] William D. Callister, and David G. Rethwisch, “Diffusion” in Materials Science and Engineering, 8th edition, John Wiley & Sons, Asia, pp. 123-126, 2011
[23] Gordon Roberts. “History's Influence on Screen Printing's Future,” Available from: http://www.screenweb.com/content/historys-influence-screen-printings-future#.WvlCHWiFPIV, [cited 14, May, 2018],
[24] “Fine Line Screen Printing of Thick Film Pastes on Silicon Solar Cells,” Available from: https://www.azom.com/article.aspx?ArticleID=10079, [cited 14, May, 2018]
[25] 羅聖全, “科學基礎研究之重要利器—掃描式電子顯微鏡(SEM),” 科學研習, Vol.52-5, pp. 2-4, 2013
[26] 何政恩, and 高振宏, “SEM/EDS的原理與操作應用之簡介,” 化工技術, Vol. 119, pp. 102-115, 2003
[27] Dr Prashant Mudgal et al., “Characteristic radiation,” Available from: radiopaedia.org/articles/characteristic-radiation, [cited 14, May, 2018]
[28] “Characteristic X-rays,” Available from: www.ammrf.org.au/myscope/analysis/eds/xraygeneration/characteristic/, [cited 14, May, 2018]
[29] Pradyot Patnaik, “X-ray methods,” in Dean's Analytical Chemistry Handbook, 2nd edition, McGraw-Hill Education, United States, pp. 9-20, 2004
[30] 鄭信民, and 林麗娟, “X光繞射應用簡介,” 工業材料雜誌, Vol. 181, pp.100-108, 2002
[31] “X-ray diffraction—XRD,” Available from: particle.dk/methods-analytical-laboratory/xrd-analysis/, [cited 14, May, 2018]
[32] ”X-ray powder diffraction (XRD),” Available from: http://www.eag.com/x-ray-diffraction-xrd/, [cited 14, May, 2018]
[33] Cristopher Hammond, The Basics of Crystallography and Diffraction, 3rd edition, Oxford University Press, New York, pp. 198-209, 2009
[34] David Brandon, and Wayne D. Kaplan, “Focused Ion Beam Microscopy,” in Microstructural Characterization of Materials, 2nd edition, Jon Wiley & Sons, England, pp. 301-315, 2008
[35] David Brandon, and Wayne D. Kaplan, “Transmission Electron Microscopy,” in Microstructural Characterization of Materials, 2nd edition, Jon Wiley & Sons, England, pp. 139-238, 2008