Slurry erosion is one of the main failure modes of the hydraulic turbine parts, mud pumps and drill pipes. The high velocity oxygen fuel (HVOF) spray process has been widely used for depositing protective coatings especially the cermet coatings that can significantly improve the slurry erosion resistance of substrate materials. In this work, conventional WC-10Co4Cr composite coatings and coatings with bimodal structures were deposited on the 35CrMo steel substrate by HVOF, respectively. Structures of the two kinds of coatings were analysed with SEM and XRD methods, and microhardness, porosity and roughness were also measured. Furthermore, the slurry erosion tests were carried out on the coatings to explore the effect of average particle size, slurry concentration and pH value on the erosion behaviours. The erosion failure mechanisms of the coatings were also explored. The results show that the bimodal coating has a denser microstructure, superior mechanical properties, lower porosity and better slurry erosion resistance than the conventional coating. The erosion-corrosion mechanism of the two kinds of coatings is spalling, caused by crack initiation and propagation under fatigue stress.
AllenC, BallA.A review of the performance of engineering materials under prevalent tribological and wear situations in South African industries. Tribol Int. 1996;29(2):105–116. doi: 10.1016/0301-679X(95)00073-D
2.
SantaJF, BaenaJC, ToroA.Slurry erosion of thermal spray coatings and stainless steels for hydraulic machinery. Wear. 2007;263:258–264. doi: 10.1016/j.wear.2006.12.061
3.
Mann BS, AryaV, MaitiAK, Corrosion and erosion performance of HVOF/TiAlN PVD coatings and Candidate materials for high pressure Gate Valve Application. Wear. 2006;260(1):75–82. doi: 10.1016/j.wear.2004.12.045
4.
LiuJJ, LiSZ, ZhouPA, Principle of material wear and its wear resistance. Beijing (BJ
): Tsinghua University Press; 1993; p. 172–193.
5.
HongS, WuY, GaoW, Slurry erosion-corrosion resistance and microbial corrosion electrochemical characteristics of HVOF sprayed WC-10Co-4Cr coating for offshore hydraulic machinery. Int J Refract Metals Hard Mater. 2018;74:7–13. doi: 10.1016/j.ijrmhm.2018.02.019
GoyalDK, SinghH, KumarH, Slurry erosion behaviour of HVOF sprayed WC–10Co–4Cr and Al2O3 +13TiO2 coatings on a turbine steel. Wear. 2012;289(13):46–57. doi: 10.1016/j.wear.2012.04.016
8.
KumarA, SharmaA, GoelSK.Erosion behaviour of WC–10Co–4Cr coating on 23-8-N nitronic steel by HVOF thermal spraying. Appl Surf Sci. 2016;370:418–426. doi: 10.1016/j.apsusc.2016.02.163
9.
PeatT, GallowayAM, ToumpisAI, Evaluation of the synergistic erosion-corrosion behavior of HVOF thermal spray coatings. Surf Coat Technol. 2016;299:37–48. doi: 10.1016/j.surfcoat.2016.04.072
10.
RameshCS, SeshadriSK, IyerKJL.A survey of aspects of wear of metals. Indian J Technol. 1991;29:179–185.
11.
HussainovaI, KubarseppJ, PirsoJ.Mechanical properties and features of erosion of cermets. Wear. 2001;250(1–12):818–825. doi: 10.1016/S0043-1648(01)00737-2
12.
BolelliG, LusvarghiL, ManfrediniT, Comparison between plasma- and HVOF-sprayed ceramic coatings. Part II: tribological behaviour. Int J Surface Sci Eng. 2007;1(1):62–79. doi: 10.1504/IJSURFSE.2007.013621
13.
BolledduV, RacherlaV, BandyopadhyayPP.Comparative study of air plasma sprayed and high velocity oxy-fuel sprayed nanostructured WC-17 wt % Co coatings. Int J Adv Manufacturing Technol. 2016;84(5–8):1601–1613.
14.
PawlowskiL.The science and engineering of thermal spray coatings. 2nd ed. Hoboken (NJ
): John Wiley & Sons; 2008; p. 67–113.
15.
ChivavibulP, WatanabeM, KurodaS, Effect of powder characteristics on properties of Warm-sprayed WC-Co coatings. J Therm Spray Technol. 2010;19(1-2):81–88. doi: 10.1007/s11666-009-9438-7
16.
ShipwayPH, MccartneyDG, SudaprasertT.Sliding wear behaviour of conventional and nanostructured HVOF sprayed WC–Co coatings. Wear. 2005;259(7–12):820–827. doi: 10.1016/j.wear.2005.02.059
17.
ThakurL, AroraN.A study of processing and slurry erosion behaviour of multi-walled carbon nanotubes modified HVOF sprayed nano-WC-10Co-4Cr coating. Surf Coat Technol. 2016;309:860–871. doi: 10.1016/j.surfcoat.2016.10.073
StewartDA, ShipwayPH, MccartneyDG.Abrasive wear Behaviour of Conventional and Nanocomposite HVOF-sprayed WC-Co Coatings. Wear. 1999;225(4):789–798. doi: 10.1016/S0043-1648(99)00032-0
20.
WangQ, ChenZH, DingZX.Performance of abrasive wear of WC-12Co coatings sprayed by HVOF. Tribol Int. 2009;42(7):1046–1051. doi: 10.1016/j.triboint.2009.02.011
21.
DingX, ChengXD, YuanCQ, Structure of micro-nano WC-10Co4Cr coating and cavitation erosion resistance in NaC1 solution. Chin J Mech Eng. 2017;30(5):1239–1247. doi: 10.1007/s10033-017-0162-9
22.
BarberJ, MellorBG, WoodRJK.The development of sub-surface damage during high energy solid particle erosion of a thermally sprayed WC–Co–Cr coating. Wear. 2005;259(1):125–134. doi: 10.1016/j.wear.2005.02.008
23.
HadadM, HitzekR, BuerglerP, Wear performance of sandwich structured WC–Co–Cr thermally sprayed coatings using different intermediate layers. Wear. 2007;263(1–6):691–699. doi: 10.1016/j.wear.2006.12.057
ArjiR, DwivediDK, GuptaSR.Sand slurry erosive wear of thermal sprayed coating of stellite. Surf Eng. 2013;23(5):391–397. doi: 10.1179/174329407X247145
26.
StewartDA, ShipwayPH, MccartneyDG.Microstructural evolution in thermally sprayed WC–Co coatings: comparison between nanocomposite and conventional starting powders. Acta Mater. 2000;48(7):1593–1604. doi: 10.1016/S1359-6454(99)00440-1
27.
SudaprasertT, ShipwayPH, MccartneyDG.Sliding wear behaviour of HVOF sprayed WC–Co coatings deposited with both gas-fuelled and liquid. Wear. 2003;255(7):943–949. doi: 10.1016/S0043-1648(03)00293-X
28.
PadhyMK, SainiRP.Effect of size and concentration of silt particles on erosion of Pelton turbine buckets. Energy. 2009;34(10):1477–1483. doi: 10.1016/j.energy.2009.06.015
29.
BajracharyaTR, AcharyaB, JoshiCB, Sand erosion of Pelton turbine nozzles and buckets: A case study of Chilime Hydropower Plant. Wear. 2008;264(3):177–184. doi: 10.1016/j.wear.2007.02.021
30.
LiuY, FischerTE, DentA.Comparison of HVOF and plasma-sprayed alumina/titania coatings-microstructure, mechanical properties and abrasion behavior. Surf Coat Technol. 2003;167(1):68–76. doi: 10.1016/S0257-8972(02)00890-3
31.
SantaJF, BaenaJC, ToroA.Slurry erosion of thermal spray coatings and stainless steels for hydraulic machinery. Wear. 2007;263(1):258–264. doi: 10.1016/j.wear.2006.12.061
