臺灣博碩士論文加值系統

近年來，鉻金屬鍍層可以從使用甲酸、乙酸或氨基乙酸等為錯合劑的三價鉻鍍液中獲得，然而，在三價鉻電沉積工作中，對於要如何提高鍍液的穩定性及增加電流效率和沉積速率仍然無法獲得良好的解決。在這個研究中，鉻金屬鍍層將由不同種類錯合劑所形成的三價鉻鍍液中獲得，同時這些三價鉻金屬鍍層的硬度、表面形貌及電化學測試將會被量測與觀察。基於實驗的結果，一個適當並且可行的三價鉻鍍液在此被提出。在這個新提出的三價鉻鍍液中，當鍍液溫度為30℃且電流密度為50 ~70 A/dm2時，其電沉積之電流效率可達到85%。這個重要的改進，主要是歸功於在鍍液中添加適合的錯合劑種類及導電鹽類。
對於退火後的三價鉻金屬鍍層之硬度、X-ray分析儀(XRD)及腐蝕抵抗的量測方面。當三價鉻金屬鍍層在經過1小時600℃退火後，其鉻金屬鍍層之硬度可以提高到約1400 Hv。根據X-ray分析儀(XRD)量測的結果，鉻金屬鍍層之硬度的增加，主要在於退火進行期間，其鉻金屬鍍層中有Cr7C3形式的碳化鉻析出。三價鉻金屬鍍層在空氣中經過1小時700℃退火後，其腐蝕抵抗能力明顯的提升。在鍍層中，鍍層裂縫中的構成物是增進其腐蝕抵抗能力的主要緣由。當鍍層裂縫中沒有Cr2O3的存在時，在鍍層底部的鋼基材將會透過鍍層裂縫的發展而被優先侵蝕。
在最後的章節中，從這個新提出來的三價鉻-鎳鍍液中所獲得的鉻-鎳合金鍍層與鉻-鎳multilayers之特性在此被提出。當電鍍之電流密度為10 A/dm2時，其所獲得的鍍層之成份主要以鎳金屬為主，而電鍍之電流密度為40 A/dm2時，則鍍層之成份主要以鉻金屬為主。因此，藉由脈衝電流之電鍍方式，進而發展出每層厚度為數十奈米的鉻-鎳multilayers。鉻-鎳multilayers的顯微結構已經藉由穿透式電子顯微鏡(TEM)及歐傑電子分析儀(AES)進行解析。

Presently, chromium deposits could be obtained from trivalent chromium baths using formate and acetate, or glycine complex at 30℃. However, bath stability, relatively low plating current efficiency and deposition rate of trivalent chromium electroplating are still not well solved. In this study, the chromium deposit obtained from trivalent chromium plating bath with different complex formers was conducted. Meanwhile, the property of deposit was evaluated by means of hardness measurement, morphology examination, microstructure charization and electrochemical test. Based on the experimental results, a suitable and practicable trivalent plating bath was proposed. With the bath, high current efficiency of electroplating was recognized. The highest current efficiency of trivalent chromium electroplating can reach as high as 85% at 50 - 70 A/dm2 and 30℃. This improvement is attributed to suitable complex formers and conducting salts added in the plating bath.
The annealing behavior of hard chromium deposit was studied with x-ray diffractrometer, hardness and corrosion resistance tests. The highest hardness of chromium deposit could be raised to ca. 1400 Hv after the annealing at 600C for 1 hour. According to the results of X-ray diffractrometer, hardness increase is resulted from precipitation of Cr7C3 in the deposit during annealing. The corrosion resistance of trivalent chromium deposit could be increased after annealing at 700C for 1 hour in the air furnace. Formation of within deposit cracks in the deposit is the main ground for improving its corrosion resistance. Without Cr2O3 within cracks, steel substrate was preferred etched through cracks developed in the deposit.
The behavior of both chromium-nickel deposit and chromium rich –nickel rich multilayer obtained from the proposed plating bath were reported at last section. The chemical composition of chromium-nickel deposit depends strong on plating current density. At plating current density of 10 A/dm2, the nickel-rich deposit was obtained, while at 40 A/dm2, the chromium-rich deposit was formed. Hence, pulsed-current electroplating was used to develop chromium- and nickel-rich multilayer with a thickness modulation of tens of nanometers. Microstructures of chromium-nickel multilayers were investigated by transmission electron microscopy and auger electron spectrometer.

指導教授推薦書
口試委員會審定書
授權書
誌謝 iv
中文摘要 v
ABSTRACT vii
CONTENTS ix
TABLE CONTENTS xiii
FIGURB CONTENTS xiv

1. Introduction 1
1.1 Metal electrodeposition 1
1.2 Physical crystallization 2
1.2.1 Nucleation of physical crystallization 3
1.2.2 Growth of physical crystallization 3
1.3 Electrocrystallization 3
1.3.1 Nucleation of electrocrystallization 5
1.3.2 Growth of electrocrystallization 6
1.4 Effects of electrodeposition parameters 7
1.4.1 Effects of current density on electrodeposition 8
1.4.2 Pulsed electrolysis deposition 8
1.4.3 Effects of bath temperature on electrodeposition 10
1.4.4 Effects of additive on electrodeposition 11
1.5 Chromium electrodeposition 12
1.6 High-carbon tool steel 13
1.7 Trivalent chromium electrodeposition 14
1.8 Literature review of trivalent chromium electrodeposition 14
1.8.1 Electrodeposition using the formate and acetate complex 15
1.8.2 Electrodeposition using the urea complex 16
1.8.3 Electrodeposition using the glycine complex 17
1.9 Chromium-nickel alloys electrodeposition 18
1.10 Chromium-nickel multilayers electrodeposition 18

2. Objective of the investigation 24

3. Experimental tools and techniques 25
3.1 Substrate pretreatment and electrodeposition cell design 25
3.2 Trivalent chromium electrodeposition parameters 26
3.3 Surface morphology and microstructure examination 26
3.3.1 Scanning electron microscope (SEM) 27
3.3.2 X-ray diffraction (XRD) 28
3.3.3 Transmission electron microscope (TEM) 29
3.4 Electrochemical analyses 29
3.4.1 Potentiodynamic polarization 30
3.4.2 Cyclic Voltammetry (CV) 30
3.4.3 A.C. Impedance 31

4. Results and discussion 34
4.1 Preliminary study of trivalent chromium electroplating technique 34
4.2 Trivalent chromium deposits obtained from the plating bath with formate and acetate complex formers 36
4.2.1 Surface morphology 36
4.2.2 Hardness measurement 37
4.2.3 Potentiodynamic polarization measurement 37
4.3 Developing decorative chromium deposits from trivalent chromium bath by using glycine as complex formers 44
4.3.1 Surface characteristics of bright chromium deposits 44
4.3.2 Potentiodynamic polarization measurement 45
4.3.3 Potentiostatic measurement 46
4.4 The proposed plating bath for trivalent chromium electro- deposition 58
4.4.1 Current efficiency measurement 58
4.4.2 Surface morphology observation 60
4.4.3 Hardness measurement 61
4.4.4 X-ray diffraction measurement 62
4.5 Electrochemical measurement of trivalent chromium deposits electroplated from proposed plating bath 73
4.5.1 Anodic polarization behavior 73
4.5.2 Potentiostatic etching 74
4.5.3 AC impedance test 76
4.5.4 Microscope study 77
4.6 Chromium-nickel alloys electrodeposition from proposed trivalent chromium-nickel bath 90
4.6.1 Chromium-nickel electrodeposition 90
4.6.2 Pulse-current plating 91
4.6.3 Study of electrodeposits by transmission electron microscopy 92

5. Conclusions 100

6. Future work 102

REFERENCE 103

Publication List 109

[1] Milan Paunovic and Mordechay Schlesinger, Fundamentals of electro- chemical deposition, John Wiley & Sons, Inc., 1998.
[2] Mordechay Schlesinger and Milan Paunovic, Morden electroplateing, John Wiley & Sons, Inc., 2000.
[3] Bockris J.O’M and Razumney G. A. Fundamental aspects of Elecntro- crystallization , New York: plenum., 1967.
[4] Rolf Weil and R.G. Barradas, Proceedings of the symposium on electrocrystallization, Pennington, NJ (10 S. Main St., Pennington 08534) :Electrochemical Society., 1981.
[5] Milchev Alexander, Electrocrystallization: fundamentals of nucleation and growth, Boston, Mass. :Kluwer Academic Publishers., 2002.
[6] I. H. Warren, “Application of polarization measurements in the control of metal Deposition”, Process Metallurgy, 3, pp. 49, 1984.
[7] Vetter K. J, “Elektrochemische Kinetik“, Berlin Springer Verlag, pp. 698, 1961.
[8] Fischer H, “The nucleation dependent growth layer, structure element in Electrocrystallization”, Plating, 56, pp. 1229-1233, 1969.
[9] P. Sarkar and P. S. Nicholson, “Electrophoretic Deposition (EPD) Mechanisms, Kinetics, and Application to Ceramics”, Journal of the American Ceramic Society, 79, 8, pp. 1987-2002, 1996.
[10] E. Mechailova, I. Vitanova, D. Stoychev and A. Milchev, “Initial stages of copper electrodeposition in the presence of organic additives”, Electrochimica Acta, 38, pp. 2455-2458, 1993.
[11] K. Kondo, K. Kojima, N. Ishida and M. Irie, “Effects of 2,2' Dipyridyl on Electroless Copper Deposition in the Presence of Excess Triethanolamine” Journal of the Electrochemical Society, 140, pp.1598-1600, 1993.
[12] J. K. Dennis and T. E. Such, Nickel and chromium plating, 3rd Ed, Woodhead Publishing, Ltd., 1994.
[13] J. C. Saiddington and G. R. Hony, “Chromium plating from a low- ratio sulfate bath. Improvement by addition of sodium hydroxide”, Plating, 57, 11, pp. 1112-1116, 1970.
[14] J. C. Saiddington and G. R. Hony, “Study of transient processes preceding the electrodeposition of Cr on Pt”, Journal of the Electro- chemical Society, 120, pp. 1475-1484, 1973.
[15] J. C. Saiddington and G. R. Hony, “Crack-free chromium from conventional plating baths”, Plating, 61, 10, pp 923-930, 1974.
[16] G. A. Lausmann, “Electrolytically deposited hardchrome”, Surface and Coatings Technology, 86-87, 1-3, pp. 814-820, 1996.
[17] J. Pina, A. Dias, M. Francois, J. L. Lebrun, “Residual stresses and crystallographic texture in hard-chromium electroplated coatings”, Surface and Coatings Technology, 96, 2-3, pp. 148-162, 1997.
[18] M. R. Bayati, M. H. Shariat, K. Janghorban, “Design of chemical composition and optimum working conditions for trivalent black chromium electroplating bath used for solar thermal collectors”, Renewable Energy, 30, pp. 2163-2178, 2005.
[19] C. A. Huang, W. Lin, M. J. Liao, “The electrochemical behaviour of the bright chromium deposits plated with direct- and pulse- current in H2SO4”, Corrosion Science, 48, pp. 460-471, 2006.
[20] T. Pearson, E. Long, “Electrodeposition from trivalent chromium electrolytes”, Transactions of the Institute of Metal Finishing, 76, 6, pp. B83-B85, 1998.
[21] J. J. B. Ward, I. R. A. Christie, “Electrodeposition from trivalent chromium salts”, Transactions of the Institute of Metal Finishing, 49, pt4, pp. 148-12, 1971.
[22] C. Barnes, J. J. B. Ward, J. R. House, “Development of a wholly, wholly inorganic trivalent chromium plating process” Transactions of the Institute of Metal Finishing, 55, pt2, pp. 73-77, 1997.
[23] D. Smart, T. E. Such, S. J. Wake, “Novel trivalent chromium electroplating baths”, Transactions of the Institute of Metal Finishing, 61, pt3, pp. 105-111, 1983.
[24] A. Watson, M. EI-Sharif, C. U. Chisholm, “Role of chromium II and IV in electrodeposition of chromium nickel alloys from trivalent chromium-amid electrolytes”, Transactions of the Institute of Metal Finishing, 64, pt4, pp. 149-153, 1986.
[25] Z. -M. Tu, Z. -L. Yang, J. -S. Zhang, “Pulse plating with a trivalent chromium plating bath”, Plating and Surface Finishing, 77, 10, pp. 55-57, 1990.
[26] Y. B. Song and D. -T. Chin, “Pulse plating of hard chromium from trivalent baths”, Plating and Surface Finishing, 87, 9, pp. 80-87, 2000.
[27] Y. B. Song and D. -T. Chin, “Current efficiency and polarization be- havior of trivalent chromium electrodeposition process”, Electro- chimica Acta, 48, pp. 349-356, 2002.
[28] S. Duan, H. Li, X. Zhang, G. Sun and J. Dash, “Hard chromium plating from a trivalent plating bath”, Plating and Surface Finishing, 82, 6, pp. 84-86, 1995.
[29] S. K. Ibrahim, A. Watson, D. T. Gawne, “The role of formic acid and methanol on speciation rate and quality in the electrodeposition of chromium from trivalent electrolytes”, Transactions of the Institute of Metal Finishing, 75, 5, pp. 181-188, 1997.
[30] M. EI-Sharif, S. Ma and C. U. Chisholm, “Environmentally acceptable process for electrodeposition of hard chromium from chromium (III) electrolyte”, Transactions of the Institute of Metal Finishing, 73, 1, pp. 19-25, 1995.
[31] M. EI-Sharif and C. U. Chisholm, “Characteristics of electro- deposited chromium”, Transactions of the Institute of Metal Finishing, 75, 6, pp. 208-212, 1997.
[32] M. EI-Sharif, J. McDougall and C. U. Chisholm, “Electrodeposition of thick chromium coatings from an environmentally acceptable chromium (III)-glycine complex”, Transactions of the Institute of Metal Finishing, 77, 4, pp. 139-144, 1999.
[33] A. G. Dolati, M, Ghorbani and A. Afshar, “The electrodeposition of quaternary Fe-Cr-Ni-Mo alloys from the chloride-complexing agents electrolyte. Part I. Processing”, Surface and Coatings Technology, 166, pp. 105-110, 2003.
[34] M. Lakatos-Varsanyi, A. Miko, L.K. Varga and E. Kalman, “Electro- deposited magnetic multi-nano-layers”, Corrosion Science, 47, 3, pp. 681-693, 2005.
[35] S. M. A. Haseeb, J. P. Cellis and J. R. Roos, “Dual-bath electro- deposition of Cu/Ni compositionally modulated multilayers”, Journal of the Electrochemical Society, 141, 1, pp. 230-237, 1994.
[36] D. R. Gabe, “Protective layered electrodeposits”, Electrochimica Acta, 39, 8-9, pp. 1115-1121, 1994.
[37] Ch. Bonhote, D. Landolt, “Microstructure of Ni-Cu multilayers electrodeposited from a citrate electrolyte”, Electrochimica Acta, 42, 15, pp. 2407-2717, 1997.
[38] C. N. Panagopoulos, V. D. Papachristos and L. W. Christoffersen, “Lubricated sliding wear behaviour of Ni-P-W multilayered alloy coatings produced by pulse plating”, Thin Solid Films, 366, 1-2, pp. 155-163, 2000.
[39] J. J. Kelly, P. Bradley and D. Landolt, “Additive Effects during Pulsed Deposition of Cu-Co Nanostructures”, Journal of the Electro- chemical Society, 147, pp. 2975, 2000.
[40] S. M. S. I. Dulal, E. A. Charles and S. Roy, “Characterisation of Co-Ni(Cu)/Cu multilayers deposited from a citrate electrolyte in a flow channel cell”, Electrochimica Acta, 49, 12, pp. 2041-2049, 2004.
[41] S.C. Kwon , M. Kim , S.U. Park , D.Y. Kim , D. Kim , K.S. Nam , Y. Choi, “Characterization of intermediate Cr-C layer fabricated by electrodeposition in hexavalent and trivalent chromium baths”, Surface and Coatings Technology, 183, pp. 151-156, 2004.
[42] Tz. Boiadjieva, D. Kovacheva, K. Petrov, S. Hardcastle, M. Monev, “Effect of anodic treatment on the composition and structure of electrodeposited Zn-Cr alloy coatings” Corrosion Science, 46, 3, pp. 681-695, 2004.
[43] L. Sziraki, E. Kuzmann, M. El-Sharif, C.U. Chisholm, G. Principi, C. Tosello, A. Vertes, “Electrochemical behavior of electrodeposited strongly disordered Fe-Ni-Cr alloys”, Electrochemistry Comm- unications, 2, pp. 619-625, 2000.
[44] C. A. Huang, K. C. Li, W. Lin, M. C. Liao, “The behavior of electro- plated hard-chromium on Cr-Mo steel subject to long-term annealing at 250℃”, Materials Science and Engineering. A, 46, pp. 222-226, 2005.
[45] M. Kim, S. U. Park, D. Y. Kim, S. C. Kwon, Y. Choi, “Charac- terization of chromium-carbon layer fabricated by electrodeposition in trivalent chromium bath“, Materials Science Forum, 475-479, pp. 3823-3826, 2005.
[46] S. S. Abd El Rehim, M. A. M. Ibrahim, M. M. Dankeria, “Thin films of chromium electrodeposition from a trivalent chromium electrolyte”, Transactions of the Institute of Metal Finishing, 80, 1, pp. 29-33, 2002.
[47] D. Landolt, A. Marlot, “Microstructure and composition of pulse- plated metals and alloys”, Surface and Coatings Technology, 160-170, 1, pp. 8-13, 2003.
[48] Feng Wang, Tohru Watanabe, “Preparation and characterization of the electrodeposited Fe-Cr alloy film”, Materials Science and Engineering. A, 349, 1-2, pp. 183-190, 2003.
[49] A. A. Edigaryan, V. A. Safonov, E. N. Lubnin, L. N. Vykhodtseva, G. E. Chusova, Yu. M. Polukarov, “Properties and preparation of amorphous chromium carbide electroplates”, Electrochimica Acta, 47, 17, pp. 2775-2786, 2002.