Mechanical and microMechanical and microstructural characterization of yttria-stabilized zirconia (Y2O3/ZrO2; YSZ) nanopartstructural characterization of yttria stabilized zirconia (Y2O3/ZrO2; YSZ) nanoparticles reinforced WC-10Co-4Cr coated turbine steel

Abstract

The aim of this paper is to investigate the WC-10Co-4Cr coatings reinforced with 5 % and 10 % of yttria-stabilized zirconia (Y2O3/ZrO2; YSZ) nanoparticles deposited on the CA6NM turbine steel by using the high-velocity oxy-fuel (HVOF) thermal spraying technique. In the HVOF technique, the hot jet of the semi-solid particles strikes against the workpiece and creates a layer of coating of varying thickness on the substrate material. The coatings fabricated with HVOF were analyzed by scanning electron microscope (SEM) / energy-dispersive x-ray spectroscopy (EDS). The phase identification of a crystalline material was made with the x-ray diffraction (XRD) technique. The mecha­nical properties in terms of porosity, surface roughness and microhardness of the nanocomposite coatings were also evaluated. The SEM/EDS analysis showed that dense and homogeneous coatings were developed by the reinforcement of YSZ nanoparticles. The peaks of XRD graphs of WC-10Co-4Cr coating reinforced with 5 and 10 % of YSZ nanoparticles revealed that the WC was present as a major phase and W2C, Co3W3C, Co, Co6W6C, Co6W and Y2O3/ZrO2 nanoparticles were observed as a minor phase. The porosity level decreased up to 42 and 56 % by the addition 5 and 10 % of YSZ nanoparticles as compared with conventional WC-10Co-4Cr coating. The surface roughness values for WC-10Co-4Cr conventional coating, 95 % (WC-10Co-4Cr) + 5 % YSZ and 90 % (WC-10Co-4Cr) + 10 % YSZ nanocomposite coated samples were found to be 5.03, 4.89 and 4.28 respectively. The nanocomposite coatings reinforced with 10 % YSZ nanoparticles exhibited the highest microhardness value (1278 HV). The WC-10Co-4Cr coatings reinforced with 10 % of YSZ nanoparticles resulted in low porosity, low surface roughness and high microhardness. During the coating process, the nanoparticles of YSZ flow into the pores and are dispersed in the gaps between the micrometric WC particles and provide a better shield to the substrate material. The WC-10Co-4Cr with 10 % of YSZ nanoparticles showed better results in terms of mecha­nical and microstructural properties during the investigation.

Effect of nano yttria-stabilized zirconia on properties of Ni-20Cr composite coatings

“…The increase in hardness has been attributed by Porthina et al [27] and Kumar et al [28] to the decrease in porosity. Due to the closure of porosities, the inclusion of YSZ nanoparticles increased the resistance to indentation.…”

Microhardness and biological behavior of AZ91D-nHAp surface composite for bio-implants

“…EDX analysis has been performed to confirm the composition of the material's composition as claimed by the manufacturer, as shown in Figure 3 [30]. Figure 4 shows the SEM image of the nano-HAp reinforcement powder particles.…”

Correlation study of random deposition for WC–12Co multiparticles on the TC18 substrates

“…They revealed the evolution of temperature, strain, and stress fields during particle deposition and analyzed the formation mechanism of coating pore. In the same year, Kumar et al 9 used HVOF technology to deposit YSZ nanoparticles on the surface of CA6NM turbine steel. The WC-10Co-4Cr coatings reinforced by 5% and 10% yttrium-stabilized zirconia (Y 2 O 3 /ZrO 2 ) were studied.…”