Thermal spraying has emerged as a suitable and effective surface engineering technology and is widely used to apply wear, erosion and corrosion protective coatings for various kinds of industrial applications. Cr 3 C 2 -based coatings have been applied to a wide range of industrial components. Cr 3 C 2 -NiCr coatings offer greater corrosion and oxidation resistance, also having a high melting point and maintaining high hardness, strength and wear resistance up to a maximum operating temperature of 900 °C. The corrosion resistance is provided by NiCr matrix while the wear resistance is mainly due to the carbide ceramic phase. This paper reviews the performance, developments and applications of Cr 3 C 2 -NiCr thermal spray coatings for corrosion/erosion-corrosion under different types of environments and outlines the characterization of Cr 3 C 2 -NiCr coatings with respect to their microstructure and mechanical properties, together with some brief characterisation work by the author for HVOF sprayed 75Cr 3 C 2 -25NiCr coating on T91 boiler steel.
Sidhu TS, Malik A, Prakash S, Agrawal RD. Oxidation and Hot Corrosion Resistance of HVOF WC-NiCrFeSiB Coating on Ni- and Fe-based Superalloys at 800 °C. J. Therm. Spray Technol. 2007; 16(5-6); 844-849.
Mahesh RA, Jayaganthan R, Prakash S. Evaluation of hot corrosion behaviour of HVOF sprayed NiCrAl coating on superalloys at 900°C. Mater. Chem. Phys. 2008; 111; 524–533.
Kamal S, Jayaganthan R, Prakash S. Evaluation of cyclic hot corrosion behaviour of detonation gun sprayed Cr 3 C 2 –25%NiCr coatings on nickel- and iron-based superalloys. Surf. Coat. Technol. 2009; 203; 1004–1013.
Sidhu TS, Prakash S, Agrawal RD. Hot corrosion performance of a NiCr coated Ni-based alloy. Scripta Mater. 2006; 55; 179–182.
Poza P, Gran PS. Microstructure evolution of vacuum plasma sprayed CoNiCrAlY coatings after heat treatment and isothermal oxidation. Surf. Coat. Technol. 2006; 201; 2887–2896.
Sidhu HS, Sidhu BS, Prakash S. Mechanical and microstructural properties of HVOF sprayed WC–Co and Cr 3 C 2 –NiCr coatings on the boiler tube steels using LPG as the fuel gas. J. Mater. Process. Technol. 2006; 171; 77–82.
Miranda JC, Ramalho A. Abrasion resistance of thermal sprayed composite coatings with a nickel alloy matrix and a WC hard phase. Effect of deposition technique and re-melting. Tribol. Lett. 2001;11(1);37-48.
Khanna AS, Kumari S, Kanungo S, Gasser A. Hard coatings based on thermal spray and laser cladding. Int. J. of Refract. Met. H. 2009; 27; 485–491.
Roy M, Pauschitz A, Polak R, Franek F. Comparative evaluation of ambient temperature friction behaviour of thermal sprayed Cr 3 C 2 –25(Ni20Cr) coatings with conventional and nano-crystalline grains. Trib. Int. 2006; 39; 29–38.
Crawmer DE. Introduction to coatings, equipment and theory. In: Davis JR, editor. Hand book of thermal spray technology, ASM International, Materials Park, OH, USA; 2004; p. 43-46.
Bala N, Singh H, Prakash S. High-temperature oxidation studies of cold-sprayed Ni–20Cr and Ni–50Cr coatings on SAE 213-T22 boiler steel. Appl. Surf. Sci. 2009; 255; 6862– 6869.
Bolelli G, Cannillo V, Lusvarghi L, Montorsi M, Mantini FP, Barletta M. Microstructural and tribological comparison of HVOF-sprayed and post-treated M–Mo–Cr–Si (M = Co, Ni) alloy coatings. Wear 2007; 263; 1397–1416.
Tillmann W, Vogli E, Baumann I, Kopp G, Weihs C. Desirability-Based Multi-Criteria Optimization of HVOF Spray Experiments to Manufacture Fine Structured Wear-Resistant 75 Cr 3 C 2 -25(NiCr20) Coatings. J. Therm. Spray Technol. 2010; 19(1-2); 392–408.
Guilemany JM, Ferna′ndez J, Delgado J, Benedetti AV, Climent F. Effects of thickness coating on the electrochemical behaviour of thermal spray Cr 3 C 2 –NiCr coatings, Surf. Coat. Technol. 2002; 153; 107–113.
Sidhu TS, Prakash S, Agrawal RD, Hot corrosion studies of HVOF sprayed Cr 3 C 2 –NiCr and Ni–20Cr coatings on nickel-based superalloy at 900 °C. Surf. Coat. Technol. 2006; 201; 792–800.
Shi-Hong Zhang, Tong-Yul Cho, Jae-Hong Yoon, Fang W, Ki-O Song, Ming-Xi Li, Yun- Kon Joo, Lee CG. Characterization of microstructure and surface properties of hybrid coatings of WC–CoCr prepared by laser heat treatment and high velocity oxygen fuel spraying. Mater. Charact. 2008; 59; 1412-1418.
Ruhi G, Modi OP, Sinha ASK, Singh IB. Effect of sintering temperatures on corrosion and wear properties of sol–gel alumina coatings on surface pre-treated mild steel. Corros. Sci. 2008; 50; 639–649.
Wang BQ, Lee SW. Elevated temperature erosion of several thermal-sprayed coatings under the simulated erosion conditions of in-bed tubes in a fluidized bed combustor. Wear 1997; 203-204; 580-587.
Souza RC, Voorwald HJC, Cioffi MOH. Fatigue strength of HVOF sprayed Cr 3 C 2 –25NiCr and WC-10Ni on AISI 4340 steel. Surf. Coat. Technol. 2008; 203; 191–198.
Fernandez E, Garc?a JR, Cuetos JM, Higuera V. Behaviour of laser treated Cr, Ni coatings in the oxidative atmosphere of a steam boiler. Surf. Coat. Technol. 2005;195;1– 7.
Bala N, Singh H, Prakash S. An overview of characterizations and high temperature behaviour of thermal spray NiCr coatings. Int. J. Mater. Sci. 2007;2(3);201-218.
Matthews SJ, James BJ, Hyland MM. Microstructural influence on erosion behaviour of thermal spray coatings. Mater. Charact. 2007; 58; 59–64.
Kamal S, Jayaganthan R, Prakash S, Kumar S. Hot corrosion behavior of detonation gun sprayed Cr 3 C 2 –NiCr coatings on Ni and Fe-based superalloys in Na 2 SO 4 –60% V 2 O 5 environment at 900 °C. J. Alloys Compd. 2008; 463; 358–372.
Stein KJ, Schorr BS, Marder AR. Erosion of thermal spray MCr–Cr C cermet coatings. Wear 1999; 224; 153–159.
Seong BG, Hwang SY, Kimb KY. High-temperature corrosion of recuperators used in steel Mills. Surf. Coat. Technol. 2000; 126; 256-265.
Sidhu TS, Prakash S, Agrawal RD. Characterizations of HVOF sprayed NiCrBSi coatings on Ni- and Fe-based superalloys and evaluation of cyclic oxidation behaviour of some Nibased superalloys in molten salt environment. Thin Solid Films 2006; 515; 95–105.
Lawrence J, Lib L. Augmentation of the mechanical and chemical resistance characteristics of an Al 2 O 3 -based refractory by means of high power diode laser surface treatment. J. Mater. Process. Technol. 2003; 142; 461–465.
Sahraoui T, Fenineche N-E, Montavon G, Coddet C. Structure and Wear Behavior of HVOF Sprayed Cr 3 C 2 -NiCr and WC-Co Coatings. Mater. Des. 2003; 24(5); 309-313.
Lih W-C, Yang SH, Su CY, Huang SC, Hsu IC, Leu MS. Effects of Process Parameters on Molten Particle Speed and Surface Temperature and the Properties of HVOF CrC/NiCr Coatings. Surf. Coat. Technol. 2000; 133-134; 54-60.
Sidhu HS, Sidhu BS, Prakash S. The role of HVOF coatings in improving hot corrosion resistance of ASTM-SA210 GrA1 steel in the presence of Na 2 SO 4 –V 2 O 5 salt deposits. Surf. Coat. Technol. 2006; 200; 5386–5394.
Sidhu BS, Prakash S. Studies on the behaviour of stellite-6 as plasma sprayed and laser remelted coatings in molten salt environment at 900 °C under cyclic conditions. J. Mater. Process. Technol. 2006; 172; 52–63.
Wang Y. Friction and wear performances of detonation-gun- and plasma-sprayed ceramic and cermet hard coatings under dry friction. Wear 1993; 161; 69-8.
Wang BQ, Luer K. The erosion-oxidation behavior of HVOF Cr 3 C 2 -NiCr cermet coating. Wear 1994; 174; 177-185.
Wang BQ. Erosion-corrosion of coatings by biomass-fired boiler fly ash. Wear 1995; 188; 40-48.
Wang BQ. Effect of alkali chlorides on erosion-corrosion of cooled mild steel and Cr 3 C 2 - NiCr coating. Wear 1996; 199; 268-274.
Wang J, Zhang L, Sun B, Zhou Y. Study of the Cr 3 C 2 -NiCr detonation spray coating. Surf. Coat. Technol. 2000; 130; 69-73.
Mateos J, Cuetos JM, Vijande R, Ferna′ndez E. Tribological properties of plasma sprayed and laser remelted 75/25 Cr 3 C 2 /NiCr coatings. Trib. Int. 2001;34;345–351.
Wolfe DE, Eden TJ, Potter JK, Jaroh AP. Investigation and Characterization of Cr 3 C 2 -Based Wear-Resistant Coatings Applied by the Cold Spray Process. J. Therm. Spray Technol. 2006; 15(3); 400-512.
?órawski W, Kozerski S. Scuffing resistance of plasma and HVOF sprayed WC12Co and Cr 3 C 2 -25(Ni20Cr) coatings. Surf. Coat. Technol. 2008; 202; 4453–4457.
Matthews S, James B, Hyland M. The role of microstructure in the mechanism of high velocity erosion of Cr 3 C 2 –NiCr thermal spray coatings: Part 1—As-sprayed coatings, Surf. Coat. Technol. 2009; 203; 1086–1093.
Verdon C, Karimi A, Martin J-LA. Study of High Velocity Oxy- Fuel Thermally Sprayed Tungsten Carbide Based Coatings. Part 1: Microstructures. Mater. Sci. Eng. A 1998; 246; 11-14.
Tao K, Zhou X, Cui H, Zhang J. Microhardness variation in heat-treated conventional and nanostructured NiCrC coatings prepared by HVAF spraying. Surf. Coat. Technol. 2009; 203; 1406–1414.
Wang BQ, Shui ZR. Hot erosion behavior of carbide–metal composite coatings. J. Mater. Process. Technol. 2003; 143–144; 87–92.
Kamal S, Jayaganthan R, Prakash S. High temperature oxidation studies of detonation-gunsprayed Cr 3 C 2 –NiCr coating on Fe- and Ni-based superalloys in air under cyclic condition at 900 °C. J. Alloys Compd. 2009; 472; 378–389.
Sidhu TS, Prakash S, Agrawal RD. Hot corrosion and performance of nickel-based coatings. Current Sci. 2006; 90(1); 41-47.
Sundararajan G, Sudharshan PP, Jyothirmayi A, Gundakaram RC. The influence of heat treatment on the micro structural, mechanical and corrosion behaviour of cold sprayed SS 316L coatings. J of Mater Sci. 2009; 44; 2320–2326.
Wang BQ. Effect of post heat treatment and sealing on erosion resistance of several thermal sprayed coatings. Proceedings of ICSE, Southwest Jiaotong University Press, Chengdu, China, 2002; 138–143.
Matthews S, Hyland M, James B. Microhardness variation in relation to carbide development in heat treated Cr 3 C 2 –NiCr thermal spray coatings. Acta Mater. 2003; 51; 4267–4277.
Matthews S, James B, Hyland M. High temperature erosion of Cr 3 C 2 -NiCr thermal spray coatings—The role of phase microstructure. Surf. Coat. Technol. 2009; 203(9); 1144-1153.
Suarez M, Bellayer S, Traisnel M, Gonzalez W, Chicot D, Lesage J, Puchi-Cabrera ES, Staia MH. Corrosion behavior of Cr 3 C 2 –NiCr vacuum plasma sprayed coatings. Surf. Coat. Technol. 2008; 202(18); 4566–4571.