Tungsten carbides and W-C phase diagram

Kurlov, A. S.; Гусев, А. И.

doi:10.1134/s0020168506020051

Cited by 235 publications

(137 citation statements)

References 11 publications

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“…5a indicates that two g-phases-W 6 Co 6 C with a defined W/Co ratio and M 6 C with a variable W/Co ratio (expressed by the existence of JCPDS standard cards for Co 3 W 3 C and Co 2 W 4 C)-exist. At the same time, W 2 C does not exist at this temperature, as according to the W-C phase diagram [44], it is thermodynamically unstable below 1250°C. The path of carbon loss from WC-12%Co to a plain metallic composition crosses several two-and three-phase fields; the corresponding phase compositions are displayed in Fig.…”

Section: Tem Investigations Indicated Nanosized Particles Inmentioning

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: Tem Investigations Indicated Nanosized Particles Inmentioning

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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“…In the vicinity of the arc, temperatures above the melting point of W are reached, which is higher than the melting points of the compounds [68][69][70]. So, melting and segregation effects are expected.…”

Section: 72mentioning

confidence: 99%

Collection strategy, inner morphology, and size distribution of dust particles in ASDEX Upgrade

et al. 2014

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Abstract.The dust collection and analysis strategy in ASDEX Upgrade (AUG) is described. During five consecutive operation campaigns (2007)(2008)(2009)(2010)(2011), Si collectors were installed, which were supported by filtered vacuum sampling and collection with adhesive tapes in 2009. The outer and inner morphology (e.g. shape) and elemental composition of the collected particles were analysed by scanning electron microscopy. The majority of the ~50000 analysed particles on the Si collectors of campaign 2009 contain tungsten -the plasma-facing material in AUG -and show basically two different types of outer appearance: spheroids and irregularly shaped particles. By far most of the W-dominated spheroids consist of a solid W core, i.e., solidified W droplets. A part of these particles is coated with low Z material; a process which seems to happen presumably in the far scrape off layer plasma. In addition, some conglomerates of B, C, and W appear as spherical particles after their contact with plasma. By far most of the particles classified as B-, C-, and W-dominated irregularly shaped particles consist of the same conglomerate with varying fraction of embedded W in the B-C matrix and some porosity, which can exceed 50%. The fragile structures of many conglomerates confirm the absence of intensive plasma contact. Both the ablation and mobilization of conglomerate material and the production of W droplets are proposed to be triggered by arcing. The size distribution of each dust particle class is best described by a lognormal distribution allowing an extrapolation of the dust volume and surface area. The maximum in this distribution is observed above the resolution limit of 0.28 µm only for the W-dominated spheroids, at around 1 µm. The amount of W-containing dust is extrapolated to be less than 300 mg on the horizontal areas of AUG.

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“…According to the W-C phase diagram [42], W 2 C is thermodynamically unstable. Below 1250 °C it can decompose into WC and W during cooling of the WC-Co particle after impact.…”

mentioning

confidence: 99%

Structure Property Relationship of Suspension Thermally Sprayed WC-Co Nanocomposite Coatings

et al. 2014

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Tungsten carbides and W-C phase diagram

Cited by 235 publications

References 11 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

Collection strategy, inner morphology, and size distribution of dust particles in ASDEX Upgrade

Structure Property Relationship of Suspension Thermally Sprayed WC-Co Nanocomposite Coatings

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