Microstructure and Properties of Tungsten Carbide Coatings Sprayed with Various High-Velocity Oxygen Fuel Spray Systems

Schwetzke, R.; Kreye, H.

doi:10.1361/105996399770350395

Cited by 131 publications

(87 citation statements)

References 13 publications

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“…These microstructural changes were also studied by mechanical spectroscopy [26]. Depending on the chemical composition of the as-sprayed coating and heat treatment conditions, a replacement of the amorphous phase, metallic W, as well as the non-equilibrium phase W 2 C by the formation of g-phases was observed, e.g., [27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Influence of Post-treatment on the Microstructural and Tribomechanical Properties of Suspension Thermally Sprayed WC–12 wt%Co Nanocomposite Coatings

et al. 2017

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The potential to improve the tribomechanical performance of HVOF-sprayed WC-12Co coatings was studied by using aqueous WC-12Co suspensions as feedstock. Both as-sprayed and hot-isostatic-pressed (HIPed) coatings were studied. Mathematical models of wear rate based on the structure property relationships, even for the conventionally sprayed WC-Co hardmetal coatings, are at best based on the semiempirical approach. This paper aims to develop these semiempirical mathematical models for suspension sprayed nanocomposite coatings in as-sprayed and heat-treated (HIPed) conditions. Microstructural evaluations included transmission electron microscopy, X-ray diffraction and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy. The nanohardness and modulus of the coated specimens were investigated using a diamond Berkovich nanoindenter. Sliding wear tests were conducted using a ball-on-flat test rig. Results indicated that the HIPing post-treatment resulted in crystallization of amorphous coating phases and increase in elastic modulus and hardness. Influence of these changes in the wear mechanisms and wear rate is discussed. Results are also compared with conventionally sprayed high-velocity oxy-fuel hardmetal WC-Co coatings.

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Section: Introductionmentioning

confidence: 99%

Influence of Post-treatment on the Microstructural and Tribomechanical Properties of Suspension Thermally Sprayed WC–12 wt%Co Nanocomposite Coatings

et al. 2017

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“…Decarburization and formation of brittle η phases is an undesirable effect leading to a loss of the tough Co matrix. The presence of the above mentioned phases in HVOF sprayed WC-Co coatings were described in literature many times [7,8].…”

Section: Microstructurementioning

confidence: 99%

The influence of the spraying angle on properties of thermally sprayed HVOF cermet coatings

Houdková

Zahálka

Kašparová

2009

WIT Transactions on Engineering Sciences

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The tribological properties of the surfaces of parts, namely their wear resistance and friction properties, are in many cases decisive for their proper function. To improve surface properties, it is possible to create hard, wear resistant coatings by thermal spray technologies. Using these versatile coatings it is possible to increase the lifetime, reliability and safety of parts. For proper function of the surface treatment it is necessary to find and keep the optimal condition and parameters during preparation, deposition and further processing of the sprayed part. The spraying angle is one of the deposition parameters that influence the quality of thermally sprayed coatings. According to the theory, with decreasing spraying angle the process deposition efficiency decreases, whereas the porosity of coatings increases, being a cause of aggravated microstructure and mechanical properties. In this paper, the microstructure together with the basic mechanical properties and wear of WC-Co and Cr 3 C 2 -NiCr HVOF sprayed coatings were investigated in dependence of the spraying angle. For each coating, the marginal spraying angle that can be used without a significant decrease of the coating's quality was identified. With respect to the change in coating properties as well as to process deposition efficiency, the maximum 30° diversion from a normal spray direction is recommended in the case of WC-Co and 15° diversion in the case of Cr 3 C 2 -NiCr.

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“…This system was selected because of its higher particle velocities, which are in the range 1005-1118 m s −1 and a more uniform distribution of particles within the spray stream, resulting in better coating quality [5]. The coating and substrate materials were selected because of their desired combination of mechanical and thermal properties.…”

Section: Coating Depositionmentioning

confidence: 99%

“…The principal aim of this investigation was to investigate the RCF performance and failure modes of recently developed liquid fuel HVOF systems of superior coating microstructure [5] and fracture toughness (Fig. 8), and compare them to previously reported investigation on APS coatings [3].…”

Section: Failure Modesmentioning

confidence: 99%

Contact fatigue failure modes of HVOF coatings

Ahmed

2002

Wear

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The objective of this experimental study was to investigate the influence of coating thickness and contact stress fields on the performance and fatigue failure modes of thermal spray (WC-12%Co) HVOF coatings. Results of this study indicate that a non-dimensional coating thickness parameter (∆ = ξ/Ψ ), where ξ is the coating thickness and Ψ the depth of maximum shear stress, can be used as a useful index to optimise coating delamination resistance during Hertzian contact loading. Apart from the detection of a new failure mode (termed spalling), which is a rare failure mode in thermal spray coatings, results indicate that by appropriate control of coating thickness, and tribological conditions, it is possible to achieve a fatigue life in excess of 70 million stress cycles, without failure. This improvement in coating performance was attributed to improved fracture toughness of liquid fuel HVOF (JP5000) coatings. Coating failure was attributed to micro-and macrocracking within the coating microstructure. Thermal spray coatings were deposited by a JP5000 system in three different thicknesses on the surface of 440-C steel substrate cones to vary the depth of shear stress within the Hertzian stress field. Rolling contact fatigue (RCF) tests were conducted using a modified four-ball machine under various tribological conditions of contact stress, configuration and lubrication. Surface observations were made using scanning electron microscope (SEM), surface interferometry and light microscopy, whereas subsurface observations were made using die penetrant investigations.

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Microstructure and Properties of Tungsten Carbide Coatings Sprayed with Various High-Velocity Oxygen Fuel Spray Systems

Cited by 131 publications

References 13 publications

Influence of Post-treatment on the Microstructural and Tribomechanical Properties of Suspension Thermally Sprayed WC–12 wt%Co Nanocomposite Coatings

Influence of Post-treatment on the Microstructural and Tribomechanical Properties of Suspension Thermally Sprayed WC–12 wt%Co Nanocomposite Coatings

The influence of the spraying angle on properties of thermally sprayed HVOF cermet coatings

Contact fatigue failure modes of HVOF coatings

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