Investigation on Erosion Resistance of WC-Co-Cr Coatings

Güney

J. Electrochem. Sci. Eng.

2022

High-velocity air fuel (HVAF) coating processes have advantages over conventional high-velocity oxygen fuel (HVOF) processes, resulting in coatings with superior properties. The present review first provides a concise overview of HVAF coatings, highlighting their advantages over HVOF coatings. Then, the fundamentals of solid particle, slurry, and cavitation erosion are briefly introduced. Finally, the performance of HVAF coatings for erosion-resistant applications is discussed in detail. The emerging research consistently reports HVAF-coatings having higher erosion resistance than HVOF-coatings, which is attributed to their elevated hardness and density and improved microstructural features that inhibit the surface damages caused by erosion. The dominant wear mechanisms are mainly functions of particle impact angle. For instance, the removal of the binder phase at high impact angles causes the accumulation of plastic strain on hard particles (e.g., WC particles) in the matrix, forming micro-cracks between the hard particles and the matrix, eventually decreasing the erosion resistance of HVAF coatings. The binder phase of HVAF-coatings significantly affects erosion resistance, primarily due to their inherent mechanical properties and bearing capacity of hard particles. Optimizing spraying parameters to tailor the microstructural characteristics of these coatings appears to be the key to enhancing their erosion resistance. The relationship between microstructural features and erosion mechanisms needs to be clarified to process coatings with tailored microstructural features for erosion-resistant applications.

Section: Hvaf Coatings Against Solid Particle Erosionmentioning

confidence: 71%

High-velocity air fuel coatings for steel for erosion-resistant applications

Güney

J. Electrochem. Sci. Eng.

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

“…A tribological investigation of HVOF sprayed Cr 3 C 2 -25NiCr and WC-10Co-4Cr coatings under varying slurry conditions was carried out by Sharma et al 24 reveals that HVOF-sprayed WC-10Co-4Cr coatings demonstrate a lesser erosive wear compared to Cr 3 C 2 -25NiCr coatings, owing to high hardness. A study performed by Lian and Li 25 examined the solid particle erosion resistance of WC-10Co-4Cr coatings sprayed using HVOF/HVAF process under varying impingement angles. Owing to homogeneous microstructure and higher hardness, the erosion resistance of HVAF sprayed coatings surpass HVOF sprayed coatings in terms of performance.…”

Section: Introductionmentioning

confidence: 99%

Performance of HVAF sprayed WC-10Co-4Cr coating onto cast 21-4N steel for slurry erosion: Characterization and erosion rate studies

Rajanna,

Mamatha,

Prabhuswamy

et al. 2023

In this study, 86WC-10Co-4Cr powder was thermally sprayed onto cast 21-4N steel using High Velocity Air-Fuel (HVAF) technology. The deposited coating exhibited a dense structure with minimal porosity (1.0 ± 0.3%) and excellent fracture toughness (5.1 ± 0.3 MPa m1/2). Slurry erosion tests had shown that the HVAF-coated steel had significantly improved erosion resistance compared to uncoated steel, attributed to its high hardness, fracture toughness, and dense microstructure. Statistical analysis revealed that slurry velocity and impact angle were the most influential parameters. Further, Field emission scanning electron microscope (FE-SEM) image analysis showed that the coated steel exhibited a brittle mode of material removal, while the bare steel displayed a ductile mode. Overall, the study highlights the effectiveness of HVAF-sprayed 86WC-10Co-4Cr coatings in enhancing erosion resistance, providing valuable insights into the coating’s microstructure and performance under different erosion conditions.

International Thermal Spray Conference

“…On the other hand, when design changes are not possible or not enough for preventing the problem, the selection of the proper material is of main focus. To further improve components toughness and wear resistance, hard material coatings are substantially applied using thermal spray methods such as laser cladding [1], plasma spray [2], highvelocity oxyfuel [3], and cold spray [4]. The most common coating material named as "cermets" consist of hard particles such as tungsten carbides or alumina oxides dispersed in a metal matrix usually made of cobalt or nickel.…”

Section: Introductionmentioning

confidence: 99%

Erosion Behaviour of Cold Sprayed Coatings Made of CrMnFeCoNi High-Entropy Alloy or Composite Powders Containing WC Hard Particles in a Pure Nickel Matrix

Cappelli

Yin

Lupoi

2023

The performance of two distinct coating materials under alumina particle impingement was tested in this study. CrMnFeCoNi and WC-Ni coatings were applied to 2205 duplex stainless steel substrates using cold spray method with nitrogen as the process gas. In between the substrate and the high entropy alloy coating, an interlayer coating of 316 stainless steel was used. The presence of WC particles in the WC-Ni composite coatings was confirmed by SEM cross sectional inspection. Following deposition, the coatings were heat treated in an air furnace. The influence of heat treatment holding time on the WC-Ni coatings was studied using chemical analysis by X-ray diffraction. Heat treatments peak temperatures for the WC/Ni- Ni and high entropy alloy coatings were 600°C and 550°C, respectively. Coatings microhardness and porosity volume fraction were measured for all the samples. The HEA coating outperformed the WC/Ni-Ni hardness but exhibited a higher level of porosity. The coatings were then subjected to erosion experiments using alumina particles with variable impact angles (30°, 60°, and 90°). To compare the different materials, an average erosion value was calculated for each target specimen. The WC/Ni-Ni as-sprayed coating was the most effective against a 60° impingement angle. The HEA coating, on the other hand, demonstrated greater resistance to impact angles of 30° and 90°. SEM was utilized to examine the eroded areas and determine the main mechanisms of erosion.