Mechanical properties of WC coatings evaluated using instrumented indentation technique

Abstract

International audienceInstrumented indentation tests have been conducted on the surface and cross-section of the two WC based coatings obtained by means of high velocity oxygen fuel thermal spray techniques in order to investigate their mechanical properties. The yield strength of the coatings has been determined by means of the Zeng and Chiu model. In addition, the absolute hardness of the coatings has been determined by means of the modified proportional specimen resistance model. Additionally, conventional spherical indentation tests were carried out on the surface of the coatings, aimed at determining the yield strength by means of the equations employed in classical elastic contact mechanics. The analysis indicates that the yield strength determined from the Zeng and Chiu model is of 3*5 and 3*1 GPa for the WC-10Co-4Cr and WC-12Co coatings respectively. The absolute hardness of the WC-10Co-4Cr coating was found to be of 11*1 GPa, whereas that of the WC-12Co was of 9*3 GPa

Mechanical properties of WC/Co-CNT HVOF sprayed coatings

“…The maximum von Mises stress value determined for the WC CNT coating is slightly less than that of 2.6 GPa reported previously by La Barbera-Sosa et al. [25] for a HVOF WC-10Co-4Cr coating also found by means of spherical indentation techniques. These authors also reported a maximum von Mises stress value of approximately 1.9 GPa for a WC-12Co, which is quite similar to the one found in the present work for the WC CONV coating.…”

“…As shown in Figure 5, such a stress is located between approximately 30-40 μm below the coating surface. Therefore, following the approach suggested by La Barbera-Sosa et al [25], in the present work the criterion adopted for determining the coatings yield stress was that of the maximum von Mises stress associated to the smallest load which gives rise to the presence of a visible surface indent. Therefore, the yield stress of the WC CONV and WC CNT coatings can be assume to be approximately 1.8 and 2.2 GPa, respectively.…”

Comparison of Different Cermet Coatings Sprayed on Magnesium Alloy by HVOF

“…The benefits resulting from the application of coatings include, without limitation, the possibility of regeneration and restoring the usable properties of machines and equipment that operate under conditions of abrasive, erosive, and corrosive wear as well as the combination of the beneficial properties of the erosive, and corrosive wear as well as the combination of the beneficial properties of the core with resistance to wear, hardness, and heat. Depending on the source of heat used to melt the coating material, the following types of spraying can be differentiated: wire flame and powder flame spraying, crucible spraying, arc spraying, plasma spraying, and supersonic spraying [6][7][8]. The high-velocity oxygen fuel (HVOF) spraying method is one of the most commonly used methods.…”

Study of the effects of the laser remelting process on the microstructure and properties of the WC–10Co–4Cr coating sprayed by HVOF

“…The high velocity oxy-fuel (HVOF) thermal spray process is commonly used for depositing wear resistant coatings and has been successfully used for spraying ceramic coatings such as WC-Co-Cr [1][2][3]. The main applications of this technology are related to internal combustion engine shafts, compressors [4], and are widely used to protect surfaces against corrosion and wear in the petrochemical, aerospace and food industries [5,6] and also in automotive and electronics industry [7].…”