Abrasive wear behaviour of conventional and large-particle tungsten carbide-based cermet coatings as a function of abrasive size and type

Abstract

. (2011) Abrasive wear behaviour of conventional and large-particle tungsten carbide-based cermet coatings as a function of abrasive size and type. Wear, A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk Scale effects in cermet abrasionPage 1 Abrasive wear behaviour of conventional and large-particle tungsten carbide-based cermet coatings as a function of abrasive size and type AbstractAbrasive wear behaviour of materials can be assessed using a wide variety of testing methods, and the relative performance of materials will tend to depend upon the testing procedure employed. In this work, two cermet type coatings have been examined, namely (i) a conventional tungsten carbide-cobalt thermally sprayed coating with a carbide size of between 0.3 -5 µm and (ii) a tungsten carbide-nickel alloy weld overlay with large spherical carbides of the order of 50 -140 µm in diameter (DuraStell). The wear behaviour of these two materials has been examined by the use of two abrasion tests, namely the micro-scale abrasion test using both silica and alumina abrasives (typically 2-10 µm in size), and the dry sand-rubber wheel test (ASTM G65), again with both silica and alumina abrasives (typically 180 -300 µm in size). It was found that when the abrasive particles were of the same scale or larger than the mean free path between the hard phase particles, then the matrix phase was well protected by the hard phases. Testing (in both test types) with alumina abrasives resulted in wear of both the hard carbide phases and the matrix phases in both the thermally sprayed coating and the weld overlay, with the thermally sprayed coating exhibiting lower wear rates. The wear behaviour of the materials with the more industrially relevant silica abrasive was more complex; the thermally sprayed coating exhibited a lower wear rate than the weld overlay with the fine abrasive in the micro-scale abrasion test due to effective shielding of the matrix from abrasive action due to the fine reinforcement particle size. In contrast, with the coarser silica abrasive in the dry sand-rubber wheel test, the weld overlay with the large carbides was able to provide matrix protection with low rates of wear, whereas the thermally sprayed coating wore by fracture of the more brittle microstructure. These findings demonstrate the importance of selection of appropriate laboratory test procedures and abrasives to simulate behaviour of materials in service environments.

Microstructure and Cavitation Erosion Resistance of HVOF Deposited WC-Co Coatings with Different Sized WC

“…Nowadays, various surface engineering techniques, including thermal spraying, laser cladding, physical vapor deposition, chemical vapor deposition, hardening and plasma nitriding, have been developed to enhance the CE resistance of component surfaces. Among them, thermal spraying methods, such as detonation gun, plasma spraying, high velocity oxy-fuel spraying and cold spraying, have already been commercially applied to various machinery components [4][5][6][7]. Thermally sprayed WC-Co coatings have attracted much attention in the study of CE resistant coating materials in recent years due to their combination of excellent toughness and high hardness, which is necessary to CE resistance.…”

Wear and Corrosion Behavior of Tungsten Carbide Based Coating on Carbon Steel

“…As reported by other researchers, abrasive particles with an angular shape can generate wear rates higher than the rounded ones. Since finer rounded particles produce less damage on the surface, the coating would show a lower wear rate [19] [20]. Therefore, finer grain size with high volume fraction and lower mean free path, as well as high hardness leads to the excellent wear rates of WC-12Co coating.…”

Morphology studies of hydrophobic silica on filter surface prepared via spray technique

“…Another reason related to this phenomenon was due to high solvent viscosity [24]- [29]. The increase in viscosity could affects the spray process although the pressure and spray time was constant for all samples [30]- [32]. When highly viscous solution being spray, the transportation of liquid from the tank to nozzle was slow, and it was affected the amount of silica concentration on the filter surface.…”