Abrasive wear behaviour of laser clad and flame sprayed-melted NiCrBSi coatings

Abstract In this work, the influence of the processing conditions on the microstructure and abrasive wear behaviour of a NiCrBSi hardfacing alloy is analysed. The hardfacing alloy was applied in the form of coatings onto a mild steel substrate (Fe–0.15%C) by different techniques: laser cladding (LC) and flame spraying (FS) combined with surface flame melting (SFM). In both cases, the appropriate selection of the process parameters enabled high-quality, defect-free NiCrBSi coatings to be obtained. The microstructure of the coatings was analysed by scanning electron microscopy (SEM), with attached energy dispersive spectroscopy (EDS) microprobe, and by X-ray diffraction (XRD). Their tribological properties were evaluated by micro-scale ball cratering abrasive wear tests using different abrasives: diamond, SiC and WC. Microstructural characterisation showed that both coatings exhibit similar phases in their microstructure, but the phases present differ in morphology, size distribution and relative proportions from one coating to another. Wear tests showed that in three-body abrasive conditions, despite these microstructural differences, the wear behaviour is comparable for both coatings. Conversely, in two-body wear conditions with diamond particles as the abrasive, it was observed that the specific wear rate of the material is sensitive to microstructural changes. This fact is particularly apparent in LC coatings, in which the zones of the layers with higher proportions of very small hard particles present a lower wear resistance. These results indicate that it is important to have good microstructural control of this material, in order to obtain coatings with an optimized and homogeneous tribological behaviour.

[1]  Shanping Lu,et al.  Microstructure and bonding strength of WC reinforced Ni-base alloy brazed composite coating , 2002 .

[2]  W. Kurz,et al.  Microstructural effects on the sliding wear resistance of a cobalt-based alloy , 1994 .

[3]  Z. Tao,et al.  Effect of CeO2 on microstructure and corrosive wear behavior of laser-cladded Ni/WC coating , 2000 .

[4]  I. Hutchings,et al.  Transitions between two-body and three-body abrasive wear: influence of test conditions in the microscale abrasive wear test , 1999 .

[5]  A. Conde,et al.  Cladding of Ni–Cr–B–Si coatings with a high power diode laser , 2002 .

[6]  Ian M. Hutchings,et al.  Wear-mode mapping for the micro-scale abrasion test , 2003 .

[7]  J. Damborenea,et al.  Corrosion behaviour of steels after laser surface melting , 2000 .

[8]  Z. Dawei,et al.  Laser cladding of Ni-Cr3C2/(Ni + Cr) composite coating , 1998 .

[9]  T. Fischer,et al.  The effects of fuel chemistry and feedstock powder structure on the mechanical and tribological properties of HVOF thermal-sprayed WC–Co coatings with very fine structures , 2003 .

[10]  R. Colaço,et al.  On the influence of retained austenite in the abrasive wear behaviour of a laser surface melted tool steel , 2005 .

[11]  José E. Fernández,et al.  Sliding wear behaviour of plasma sprayed WC-NiCrBSi coatings at different temperatures , 2001 .

[12]  Gwidon Stachowiak,et al.  Sharpness of abrasive particles and surfaces , 2004 .

[13]  F. Nenci,et al.  Microstructural aspects of wear-resistant stellite and colmonoy coatings by laser processing , 1987 .

[14]  W. Steen,et al.  Comparison of Laser Hardfacing with Conventional Processes , 1990 .

[15]  K. Acker,et al.  Influence of tungsten carbide particle size and distribution on the wear resistance of laser clad WC/Ni coatings , 2005 .

[16]  Qiang Li,et al.  Comparison of laser-clad and furnace-melted Ni-based alloy microstructures , 2001 .

[17]  J. Damborenea.  Surface modification of metals by high power lasers , 1998 .

[18]  J. Guilemany,et al.  Tribological study of NiCrBSi coating obtained by different processes , 2003 .

[19]  R. Colaço,et al.  A model for the abrasive wear of metallic matrix particle-reinforced materials , 2003 .

[20]  Changhee Lee,et al.  Assessment of wear performance of flame sprayed and fused Ni-based coatings , 2003 .

[21]  E. Rabinowicz,et al.  A study of abrasive wear under three-body conditions , 1961 .