Effect Of WC Particle Size Research Articles

Effect of WC Particle Size on Grain Growth Inhibition in the WC-xVC-Co System

The effect of WC particle size with the addition of VC as a grain growth inhibitor was investigated during the liquid phase sintering of WC-Co system. With increasing WC particle size at the same VC content, the effect of grain growth inhibition was increased. Also, with increasing the VC content, the grain shape of WC was changed from the faceted shape to the distorted shape, and the step density of the WC grain was increased.

Adhesion properties of arc ion-plated TiN coatings with WC particle size, Co content and surface roughness

In this work, TiN coating layers were deposited on various kinds of WC–Co substrates by an arc ion plating (AIP) method. Effects of WC particle size, Co content, surface roughness on the adhesion strength and failure behavior of the AIP-TiN/substrate interface were studied using a conventional scratch test. It was found that Co had diffused out of the substrate toward the coating layer and formed a certain phase composed of Ti and Co. This phenomenon might induce strong bonding between the coating layer and the substrate. The highest critical load, approximately 110 N, was obtained at a WC particle size of 1 μm and Co content of 10 wt.%. As the WC particle size, Co content and surface roughness of the substrate increased, the critical load was reduced. Adhesion between the coating and substrate was considerably affected by both the surface morphology of the coating and the surface roughness of the substrate.

Characteristics of HVOF-Sprayed WC-Co Cermet Coatings Affected by WC Particle Size and Fuel/Oxygen Ratio

The effect of WC particle size and fuel/oxygen (F/O) ratio on the characteristics of HVOF-sprayed WC–17 mass%Co coatings was investigated. The microstructure of the coatings was dense regardless of F/O ratio, but became slightly inhomogeneous due to incomplete formation of splats with coarsening WC particle size. The unmelted WC particle size in the coatings manufactured with 1.53 \\micron mean particle size varied from 0.82 to 0.89 \\micron depending on F/O ratio, and the unmelted WC particle size in the coatings manufactured with 6.3 \\micron mean particle size ranged from 2.87 to 3.03 \\micron depending on F/O ratio. The sintered WC–17 mass%Co powder for thermal spraying consisted of WC, fcc-Co and Co3W3C phases, but the HVOF-sprayed coatings consisted of WC, W2C and W phases. The rate of phase change during spraying was significantly influenced by both raw particle size of WC and F/O ratio. As the amount of the decomposed W2C phase was more, the hardness of the coatings was higher. On the contrary, as the amount of the decomposed W phase was more, the hardness of the coatings was rather lower. Consequently, it was revealed that the W2C phase was preferable but the W phase was detrimental to the hardness of the coatings.

Effect of WC Particle Size on the Abrasive Wear of Thermally Sprayed WC-Co Coatings

Four types of WC-Co powders with different WC particle sizes are sprayed to produce WC-Co coatings with a Jet-Kote gun using a gas mixture of C2H2–30% C3H6 and pure propylene as fuel gases. The carbide size in sprayed high velocity oxy-fuel (HVOF) WC-Co coatings is measured from the microstructure. The abrasive wear of the coatings is characterized using a Suga abrasive wear tester. The abrasive wear mechanism of thermally sprayed WC-Co is discussed. The relationship between the relative wear of WC-Co coatings and carbide sizes is established according to the strength theory on hard alloy. The correlation with experimental data proves that the relative abrasive wear of WC-Co coating is proportional to square root of relative carbide size.