SAFBM of Softer Materials: An Investigation into the Micro-Cutting Mechanisms and the Evolution of Roughness Profile

Int J Applied Ceramic Tech

Bhandari

2022

The aim of the present study is to investigate the slurry erosion behavior of nanoyttria-stabilized zirconia (YSZ) reinforced Cr 3 C 2 -25NiCr ceramic nanocomposite coatings deposited on turbine steel. The Cr 3 C 2 -25NiCr coating powder, 95% (Cr 3 C 2 -25NiCr) + 5% YSZ, and 90% (Cr 3 C 2 -25NiCr) + 10% YSZ nanocomposite coating powder deposited on CA6NM steel samples by using high-velocity oxy-fuel coating technique. L 9 orthogonal array Taguchi method was used to design the experiment. Erosion tests were performed on erosion test rig under hydro accelerated conditions at different levels of various parameters. Erosion tests and analysis of variance resulted that for coated samples, velocity is the major influencing factor followed by slurry concentration, impact angle, and particle size. Velocity was the largest contributor to the mass loss, whereas particle size has the least contribution to mass loss of the coated samples. The scanning electron microscopy analysis of eroded samples revealed that craters, micropores, platelets, plowing, spalling, and so on were responsible for the mass loss of uncoated and coated samples. The incorporation of YSZ nanoparticles decreased the porosity; erodent particles cannot penetrate more deeply inside the workpiece and resulted in less erosion. It has been resulted that 95% (Cr 3 C 2 -25NiCr) + 5% YSZ and 90% (Cr 3 C 2 -25NiCr) + 10% YSZ ceramic nanocomposite coatings exhibited better erosion resistance as compared to Cr 3 C 2 -25NiCr coatings due to high microhardness and low porosity.

“…The protuberances can also be seen on the eroded surface. Francis et al 35 . and Arabnejad et al 36 .…”

Section: Resultsmentioning

confidence: 99%

Section: Effect Of Slurry Erosion On the Surface Of U Uncoated A Coat...mentioning

confidence: 99%

Slurry erosion behavior of thermally sprayed ceramic nanocomposite coatings on turbine steel

Kumar

Int J Applied Ceramic Tech

Bhandari

2022

“…The scanning electron microscope studies of eroded CA6NM revealed various wear mechanism such as micro ploughing, lip formation, platelet, small craters for indentation and micro cracking. Francis et al (2016) and Arabnejad et al (2015) have reported that for ductile materials such as metal and alloys, material removal is caused by cutting, plastic deformation and micro ploughing of solid particles, and for brittle materials such as ceramics, the cracks coalescence will take place and cause material removal by microchipping and mircocutting. Moreover, repeated impacts might have also removed protuberance from the surface of coated specimens, which might have formed during the HVOF spraying process.…”

Section: Discussionmentioning

confidence: 99%

Mechanical properties and erosive behaviour of 10TiO₂-Cr₂O₃ coated CA6NM turbine steel under accelerated conditions

2019

WJE

Purpose This paper aims to evaluate the mechanical properties and slurry erosion behaviour of 10TiO2-Cr2O3 coated turbine steel. Design/methodology/approach Slurry erosion experiments were performed on the coated turbine steel specimens using slurry erosion test rig under accelerated conditions such as rotational speed, average particle size and slurry concentration. Surface roughness tester, Vickers microhardness tester and scanning electron microscope were used to analyse erosion mechanism. Findings Under all experimental conditions, 10TiO2-Cr2O3 coated steel showed better slurry erosion resistance in comparison with Al2O3 coated and uncoated steel specimens. Each experimental condition indicated a significant effect on the erosion rate of both coatings and uncoated steel. The surface analysis of uncoated eroded specimen revealed that plastic deformation, ploughing and deep craters formation were the reasons for mass loss, whereas microchipping, ploughing and microcutting were the reasons for mass loss of coated specimens. Originality/value The present investigation provides novel insight into the comparative slurry erosion performance of high velocity oxy fuel deposited 10TiO2-Cr2O3 and Cr2O3 coatings under various environmental conditions. To form modified powder, 10 Wt.% TiO2 was added to 90 Wt.% Cr2O3.

“…These types of coatings have dense grains, which create a more homogeneous layer because material spreads more uniformly over the surface. Also, this type of surface morphology is desirable for the HVOF coating process, as it allows the better flow of the coating powder in the spray gun during the deposition of the coating [37][38][39]. Thus, WC-10Co-4Cr + 10 % YSZ nanocomposite coating performed better than the other coatings mentioned.…”

Section: Energy Kevmentioning

confidence: 99%

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

Kumar

Bhandari²,

J. Electrochem. Sci. Eng.

2022

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.