本研究將低碳鋼先進行一階段 1000 ℃滲鉻 4 小時，再選用 750 ℃與 850 ℃之 2 種滲鋁溫度進行第二階段滲鋁 0.5 ~ 2 小時，探討二階段滲鉻鋁於不同溫度和時間之相形成機制，並利用恆溫氧化與熱循
環氧化試驗來評估二階段滲鉻鋁鍍層之抗氧化性。實驗結果顯示，第一階段滲鉻鍍層由內而外可分為鐵鉻固溶相和富鉻層，第二階段 750 ℃與 850 ℃滲鋁後鍍層會隨滲鋁時間而有變化。第二階段 750 ℃滲鋁 0.5 小時，鍍層依序由內而外分為鐵鉻固溶相、 FeAl3相以及散佈在 FeAl3相的 AlCr2顆粒。由於鋁和鉻形成 AlCr2後體積大幅縮小，鋁可藉由空隙快速滲入和底材的鐵原子形成 FeAl3。隨滲鋁時間增加，鋁原子持續滲入，使 AlCr2介穩相溶解，因此鍍層有鐵鋁鉻層的產生。第二階段滲鋁 1.5 小時的總鍍層由內而外依序分為富鉻層、Fe2Al5、鐵鋁鉻層、FeAl3、富鋁層。第二階段 850 ℃滲鋁0.5 小時，鍍層由內而外分為鐵鉻固溶相、FeAl3相。隨滲鋁時間增加，滲鋁層由內而外分為鐵鉻固溶相、交互擴散層、Fe2Al5相以及散佈在Fe2Al5相的鐵鉻相(σ)。二階段 750 ℃、850 ℃滲鉻鋁試片經恆溫氧化後，氧化增重結果顯示，二階段滲鉻鋁之抗氧化性佳，提升滲鋁溫度是有助於提升抗氧化性。二階段 750 ℃、850 ℃滲鉻鋁試片經熱循環氧化後，鋁化層能抵禦外界的氧氣侵入，且無氧化物剝落。鉻元素固溶在鐵鋁相，可提升表面硬度以及抗高溫氧化能力。

In this study, the low carbon steel was firstly chromed at 1000 ℃ for 4 hours, and then the second-stage aluminized for 0.5 to 2 hours, and two kinds of aluminizing temperatures of 750 ℃ and 850 ℃ were selected to discuss the difference between the two-stage chroming and aluminum. The phase formation mechanism of temperature and time and the oxidation resistance of two-stage chromed aluminum coating was tested by constant temperature oxidation and thermal cycle oxidation test.
The experimental results show that the first stage chromizing coating can be divided into iron-chromium solid solution phase and chromium-rich layer from the inside to the outside, and the second stage after aluminizing at 750 ℃ and 850 ℃, the coating will change with the aluminizing time. The second stage is aluminized at 750 ℃ for 0.5 hours, and the coating is divided into iron-chromium solid solution phase, FeAl3 phase and AlCr2 particles dispersed in FeAl3 phase from inside to outside. Since aluminum and chromium form AlCr2, the volume is greatly reduced, and aluminum quickly infiltrates through the voids and iron atoms of the substrate to form FeAl3. As the aluminizing time increases, aluminum atoms continue to infiltrate, causing the AlCr2 metastable phase to dissolve, so the coating has an iron-aluminum-chromium layer. The total coating of the two-stage aluminizing for 1.5 hours is divided into chromium-rich layer, Fe2Al5, ironaluminum-chromium layer, FeAl3, and aluminum-rich layer from inside to outside. In the second stage, aluminizing at 850 ℃ for 0.5 hours, the coating is divided into iron-chromium solid solution phase and FeAl3 phase
from the inside to the outside. As the aluminizing time increases, the aluminizing layer is divided into Fe-Cr solid solution phase, interdiffusion layer, Fe2Al5 phase and Fe-Cr phase (σ) dispersed in Fe2Al5 phase from inside to outside. After the two-stage 750 ℃, 850 ℃ chromized aluminum test pieces were oxidized at constant temperature, the oxidation weight gain results showed that the two-stage chromized aluminum had better oxidation resistance. However, increasing the aluminizing temperature is helpful to improve the oxidation resistance. After the second-stage 750 ℃ and 850 ℃ chromized aluminum test pieces are oxidized by the thermal cycle, the aluminized layer can resist the intrusion of oxygen from the outside, and there is no oxide peeling off. It shows that the solid solution of chromium element in the iron-aluminum phase can improve the surface hardness and high-temperature oxidation resistance.

[1] A. Szczepankowski, J. Szymczak, and J. Spychała. (2009). ‘‘Operating Degradations of Air Turbine Scoops of Turbo-Engines’’. Solid State Phenomena, 147 – 149, 524 – 529.
[2] Y. Kawahara. (2007). ‘‘Application of High Temperature CorrosionResistant Materials and Coatings Under Severe Corrosive Environment in Waste-to-Energy Boilers’’. Journal of Thermal Spray Technology, 16, 202 – 213.
[3] S. H. Lee, N. J. Themelis, and M. J. Castaldi. (2007). ‘‘HighTemperature Corrosion in Waste-to-Energy Boilers’’. Journal of Thermal Spray Technology, 16, 104 – 110.
[4] J. Singh, H. Vasudev, and S. Singh. (2020). ‘‘Performance of different coating materials against high temperature oxidation in boiler tubes – A review’’. Materials Today: Proceedings, 26, 972 – 978.
[5] J. K. Min, J. H. Jeong, M. Y. Ha, and K. S. Kim. (2009). ‘‘High temperature heat exchanger studies for applications to gas turbines’’.Heat and Mass Transfer, 46, 175.
[6] C. Zhou, H. Xu, S. Gong, K. Y. Kim. (2003). ‘‘A study of aluminide coatings on TiAl alloys by the pack cementation method’’. Materials Science and Engineering: A, 341, 169 – 173.
[7] Z. G. Zhang, Y. P. Peng, Y. L. Mao, C. J. Pang, and L. Y. Lu. (2012). ‘‘Effect of hot-dip aluminizing on the oxidation resistance of Ti–6Al–4V alloy at high temperatures’’. Corrosion Science,55, 187 – 193.
[8] F. Bozza, G. Bolelli， C. Giolli, A. Giorgetti, L. Lusvarghi, P. Sassatelli, A. Scrivani, A. Candeli, and M. Thoma. (2014). ‘‘Diffusion mechanisms and microstructure development in pack aluminizing of Ni-based alloys’’. Surface and Coatings Technology, 25, 147 – 159.
[9] S. Devaraj, B. Anand, M. Gibbons, A. McDonald, and S. Chandra. (2020). ‘‘Thermal spray deposition of aluminum and zinc coatings on thermoplastics’’. Surface and Coatings Technology, 399, 126114.
[10] A. Erdogan, T. Yener, K. M. Doleker, M. E. Korkmaz, and M. S. Gök. (2021). ‘‘Low-temperature aluminizing influence on degradation of nimonic 80A surface: Microstructure, wear and high temperature oxidation behaviors’’. Surfaces and Interfaces, 25, 101240.
[11] R. L. Puurunen, and B. M. Weckhuysen (2002). ‘‘Spectroscopic Study on the Irreversible Deactivation of Chromia/Alumina Dehydrogenation Catalysts’’. Journal of Catalysis, 210, 418 – 430. [12] R. Q. Lin, C. Fu, M. Liu, H. Jianga, Z. M. Ren, A. M. Russell, and G.
H. Cao. (2017) ‘‘Microstructure and oxidation behavior of Al + Cr codeposited coatings on nickel-based superalloys’’. Surface and Coatings Technology, 310, 273 – 277.
[13] C. Y. Bai, Y. J. Luo, and C. H. Koo. (2004) ‘‘Improvement of high temperature oxidation and corrosion resistance of superalloy IN738LC by pack cementation’’. Surface and Coatings Technology, 183,74 – 78.
[14] P. F. Tortorelli, and K. Natesan. (1998). ‘‘Critical factors affecting the
high-temperature corrosion performance of iron aluminides’’. Materials Science and Engineering, 258, 115 – 125.
[15] A. Agüero, J. G. Blas, R. Muelas, A. Sánchez, and S. Tsipas. (2001) ‘‘Steam Oxidation Resistant Coatings for Steam Turbine Components : A Feasibility Study’’. Materials Science Forum, 369,939 – 946.
[16] M. S. Doolabi, B. Ghasemi, S. K. Sadrnezhaad, K. Jafarzadeh , and A. Habibollahzadeh. (2017) ‘‘Hot corrosion behavior and nearsurface microstructure of a “lowtemperature high-activity Craluminide” coating on inconel 738LC exposed to Na2SO4, Na2SO4 + V2O5 and Na2SO4 + V2O5 + NaCl at 900 °C’’. Corrosion Science 128,42 – 53.
[17] S. Mahini, S. K. Asl, T. Rabizadeh, and H. Aghajani. (2020) ‘‘Effects of the pack Al content on the microstructure and hot corrosion behavior of aluminide coatings applied on Inconel-600’’. Surface & Coatings Technology, 397, 125949.
[18] K. M. Doleker, A. Erdogan, T. Yener, A. C. Karaoglanlı, O. Uzun, M. S. Gok, and S. Zeytin. (2021) ‘‘Enhancing the wear and oxidation behaviors of the Inconel 718 by low temperature aluminizing’’. Surface & Coatings Technology, 412, 127069.
[19] Z. D. Xiang, J. S. B. Gray, and P. K. Datta. (2001) ‘‘Aluminide coating formation on nickel-basesuperalloys by pack cementation process’’. Journal of Materials Science, 36, 5673 – 5682.
[20] B. K. Gupta and L. L. Seigle. (1980) ‘‘The effect on the kinetics of pack aluminization of varying the activator’’. Thin Solid Films, 73,365 – 371.
[21] F. D. Geib and R. A. Rapp. (1993) ‘‘Simultaneous chromizing — Aluminizing coating of low-alloy steel by a halide-activated, packcementation process’’. Oxidation of Metals, 40, 213 – 228.
[22] M. C. Galetz. (2015) ‘‘Superalloys’’ (M. Aliofkhazraei, Ed.). IntechOpen, 277 – 298.
[23] C. S. Ashley, R. Bianco, N. Birks, C. J. Brinker and R. A. Cairncross. (1996) ‘‘Metallurgical and Ceramic Protective Coatings’’ (K. H. Stern, Ed.). Springer Science & Business Media
[24] P. N. Walsh, G. F. Wake, and J. B. Blocker. (1983) ‘‘Chemical Aspects of Pack Cementation in Chemical Vapor Deposition’’. E1ectrochemical. Society.
[25] S. R. Ke, J. Wang, C. Y. Zhu, and Z. D. Xiang. (2015) ‘‘On the selection of halide activators for the formation of hybrid Nialuminide/Ni coatings on creep resistant ferritic steels by low temperature pack cementation process’’. Materials Chemistry and Physics, 162, 263 – 272.
[26] 秦仕緯，低碳鋼經包覆擴散及熱浸鍍鋁處理 於熱腐蝕環境之高溫潛變，國立台灣科技大學機械工程所碩士論文，民國 108 年。
[27] A. W. Cruz, R. F. Glória, R. O. Nogueira, N. Chaia, G. Silva, and G. Rodrigues. (2020) ‘‘Fe-Cr-Si Codeposition on Nb-Si based Alloys via Halide Activated Pack Cementation to Improve Oxidation Resistance’’. Materials Research, 23, 5.
[28] Z. D. Xiang and P. K. Datta. (2005) ‘‘Effects of pack composition on the formation of aluminide coatings on alloy steels at 650 ℃’’.Journal of Materials Science, 40, 1959 – 1966.
[29] R. Bianco, M. A. Harper, and R. A. Rapp. (1991) ‘‘Codepositing elements by halide-activated pack cementation’’. JOM, 43, 68 – 73.
[30] V. A. Pavi, P. Choquet, and R. A. Rapp. (1988) ‘‘Thermodynamics of simultaneous chromizing-aluminizing in halide-activated cementation packs’’. Department of Metallurgical Engineering.
[31] Z. D. Xiang, J. S. B. Gray, and P. K. Datta. (2001) ‘‘Conditions for Codeposition of Al and Cr on Ni Base Superalloys by Pack Cementation Process’’. Surface Engineering, 17, 287 – 294.
[32] J. Hu, Y. Zhang, X. Yang, H. Li, H. Xu, C. Ma, Q. Dong, N. Guoc, and Z. Yao. (2018) ‘‘Effect of pack-chromizing temperature on microstructure and performance of AISI 5140 steel with Cr-coatings’’. Surface and Coatings Technology, 344, 656 – 663.
[33] G. H. Meier and C. Chieng. (1989) ‘‘Diffusion chromizing of ferrous alloys’’. Surface and Coatings Technology, 39/40, 53 – 64.
[34] J.W. Lee, J. G. Duh, and S. Y. Tsai.(2002) ‘‘Corrosion resistance and microstructural evaluation of the chromized coating process in a dual phase Fe–Mn–Al–Cr alloy’’. Surface and Coatings Technolog, 153,59 – 66.
[35] J. W. Lee, and J. G. Duh. (2004) ‘‘Evaluation of microstructures and mechanical properties of chromized steels with different carbon contents’’. Surface and Coatings Technolog, 177 - 178, 552 – 531.
[36] D. Wang, (1988) ‘‘Corrosion behavior of chromized and/or aluminized 2 1/4 Cr-1Mo steel in medium-BTU coal gasifier environments’’. Surface and Coatings Technology, 36, 49 – 60.
[37] F. A. P. Fernandes, S. C. Heck, C. A. Picon, G. E. Totten, and L. C. Casteletti.(2012) ‘‘Wear and corrosion resistance of pack chromised carbon steel’’. Surface Engineering, 28, 313.
[38] R Bianco. (1992) ‘‘The development and performance of chromium/reactive element-modified aluminide diffusion coatings by chloride-activated pack cementation’’. The Ohio State University ProQuest Dissertations.
[39] P. Visuttipitukul, N. Limvanutpong, and P. Wangyao. (2010) ‘‘Aluminizing of Nickel-Based Superalloys Grade IN 738 by Powder Liquid Coating’’. Materials Transactions, 51, 982 – 987.
[40] C. Houngninou, S. Chevalier, and J. P. Larpin. (2004) ‘‘Synthesis and characterisation of pack cemented aluminide coatings on metals’’. Applied Surface Science, 236, 256 – 269.
[41] K. Morsi. (2001) ‘‘Review: reaction synthesis processing of Ni–Al intermetallic materials’’. Materials Science and Engineering, 299, 1 –15.
[42] G. W. Goward and D. H. Boone. (1971) ‘‘Mechanisms of Formation of Diffusion Aluminide Coatings on Nickel-Base Superalloys’’. Oxidation of Metals, 3, 5.
[43] R. A. Cottis. (2009). ‘‘Shreir’s Corrosion’’(T. Richardson, Ed.; Vol.1). Elsevier Science Ltd.
[44] S. Samal. (1983). ‘‘High‐Temperature Oxidation of Metals’’ (Z. Ahmad, Ed.). IntechOpen.
[45] 藍威勝，Ti-6Al-4V 熱浸鋁及其高溫腐蝕特性，國立台灣科技大學機械所碩士論文，民國 109 年。
[46] 賴立霖，熱浸鍍鋁 A36 低碳鋼銲接件於氯化鈉/硫酸鈉熱腐蝕環境之高溫潛變，國立台灣科技大學機械所碩士論文，民國 107年。
[47] N. Brisk and G. H. Meier. (1983). ‘‘Introduction to High Temperature Oxidation of Metals’’. Edwar Arnold Ltd.
[48] C. Xu and W. Gao. (2000) ‘‘Pilling-Bedworth ratio for oxidation of alloys’’. Material Research Innovations, 3, 231 – 235.
[49] A. S. Khanna. (2002) ‘‘Introduction to High Temperature Oxidation and Corrosion’’. ASM International, Nevada, 10, 203 – 212.
[50] T. Yener, K. M. Doleker, and A. Erdogan. (2019) ‘‘High temperature oxidation behavior of low temperature aluminized Mirrax ESR steel’’. Materials Research Express, 6, 116407.
[51] 陳世明，矽對鐵基與鎳基合金熱浸鋁化塗層之顯微結構和高溫氧化性的影響，國立台灣科技大學機械所博士論文，民國 96 年。
[52] Z. Liu and W. Gao. (2000) ‘‘Effects of chromium on the oxidation performance of β-FeAlCr coatings’’. Oxidation of metals, 54, 189 – 209.
[53] A. G. Evans, G. B. Crumley, and R. E. Demarayt. (1983) ‘‘On the Mechanical Behavior of Brittle Coatings and Layers’’. Oxidation of Metals, 20, 193 – 216.
[54] B. Wu, E. Chang, C. Chao, and M. Tsai. (1990) ‘‘The oxide pegging spalling mechanism and spalling modes of ZrO2 8 wt.% Y2O3/Ni22Cr-10Al-1Y thermal arrier coatings under various operating conditions’’. Journal of Materials Science, 25, 1112 – 1119.
[55] K. J. Huang, J. T. Chang, A. Davison, K. C. Chen, J. L. He, C. K. Lin, A. Matthews, and A. Leyland. (2006) ‘‘Thermal cyclic performance of NiAl/alumina-stabilized zirconia thermal barrier coatings deposited using a hybrid arc and magnetron sputtering system’’. Surface and Coatings Technology, 201, 3901 – 3905.
[56] C. J. Wang, and S. M. Chen. (2006) ‘‘Microstructure and cyclic oxidation behavior of hot dip aluminized coating on Ni-base superalloy Inconel 718’’. Surface and Coatings Technology, 201,3862 – 3866.
[57] F. J. Pérez, M. P. Hierro. F. Pedraza, M. C. Carpintero, C.Gómez, and R.Tarı́n. (2001) ‘‘Effect of fluidized bed CVD aluminide coatings on the cyclic oxidation of austenitic AISI 304 stainless steel’’. Surface and Coatings Technology, 145, 1 – 7.
[58] M. B. Lin, C. J. Wang, and A. A. Volinsky. (2011) ‘‘Isothermal and thermal cycling oxidation of hot-dip aluminide coating on flake/spheroidal graphite cast iron’’. Surface and Coatings Technology, 206, 1595 – 1599.
[59] C. J. Wang, P. K. Koech, and X. Z. Lin. (2019) ‘‘High-temperature degradation mechanism of aluminide coatings on titanium alloys under cyclic oxidation at 750 °C’’. Journal of the Chinese Institute of Engineers, 42, 244 – 253.
[60] S. R. Lampman, B. R. Sanders, G. J. Anton, C. Polakowski, J. Kinson, K. Muldoon, S. D. Henry, and W. W. Scott, Jr. (2004). ‘‘ASM Handbook Volume 9: Metallography and Microstructures’’ (9th ed.). ASM International.
[61] H. Sina, J. Corneliusson, K. Turba, and S. Iyengar. (2015) ‘‘A study on the formation of iron aluminide (FeAl) from elemental powders’’. Journal of Alloys and Compounds, 636, 261 – 269.
[62] R. Khoshhal, and A. H. Zadeh. (2020) ‘‘The formation mechanism of iron aluminide phases in Fe-Al system with different raw materials ratio’’. Materials Science, 4,1 – 7.
[63] U. Burkhardt, Y. Grin, M. Ellner, and K. Peters. (1994). ‘‘Structure refinement of the iron–aluminium phase with the approximate composition Fe2Al5’’. Acta Crystallographica Section B Structural Science, 50 (3), 313 – 316.
[64] P. Matysik, S. Jóźwiak, and T. Czujko. (2015). ‘‘Characterization of Low-Symmetry Structures from Phase Equilibrium of Fe-Al System—Microstructures and Mechanical Properties’’. Materials, 8,914 – 931.
[65] H. Okamoto, M. E. Schlesinger, and E. M. Mueller. (1992). ‘‘ASM Metals Handbook Volume 3 Alloy Phase Diagrams’’, (10th Ed ).ASM International.
[66] T. Sasaki, T. Yakou. (2006). ‘‘Features of intermetallic compounds in aluminized steels formed using aluminum foil’’. Surface and Coatings Technology, 201, 2131 – 2139.
[67] M. Gich, E. A Shafranovsky, A. Roig, and A. S. Waniewska. (2005).
‘‘Aerosol nanoparticles in the Fe1−xCrx system: Room-temperature stabilization of the σ phase and σ→α-phase transformation’’. Journal of Applied Physics, 98, 24303.
[68] Z. Dong, T. Zhou, J. Liu, X. Zhang. B. Shen, W. Hu, and L. Liu.
(2019). ‘‘Effects of pack chromizing on the microstructure and anticorrosion properties of 316L stainless steel’’. Surface and Coatings Technology, 366, 86 – 96.
[69] H. Okamoto. (2008). ‘‘Al-Cr (Aluminum-Chromium)’’. Journal of Phase Equilibria and Diffusion, 29, 112 – 113.
[70] J. W. Lee, J. G. Duh, and S.Y. Tsai. (2002) “Corrosion resistance and microstructural evaluation of the chromized coating process in a dual phase Fe–Mn–Al–Cr alloy’’. Surface and Coatings Technology, 153, 59.
[71] Y. Y. Chang, C. C. Tsaur, and J. C. Rock. (2006) “Microstructure studies of an aluminide coating on 9Cr-1Mo steel during high temperature oxidation’’. Surface and Coatings Technology, 200,6588–6593.
[72] K. Gemma, Y. Satoh, I. Ushioku, and M. Kawakam.(1995)
“Abnormal nitriding behaviour of a high chromium, high manganese austenitic steel’’. Surface Engineering, 11, 240 – 245.
[73] Mohammad Badaruddin，水蒸氣對低碳鋼與熱浸鋁化低碳鋼高溫氧化之影響，國立台灣科技大學機械所博士論文，民國 100 年。
[74] 高振源，鋁矽溶湯中矽含量對熱浸鍍 310 不銹鋼高溫氧化之作用，國立台灣科技大學機械所碩士論文，民國 95 年。
[75] C. Houngniou, S. Chevalier, and J. P. Larpin.(2006) “HighTemperature-Oxidation Behavior of Iron–Aluminide Diffusion Coatings’’. Oxidation of Metals, 65, 409 – 439.