Cobalt capping on WC–Co hardmetals. Part I: A mechanism explaining the presence or absence of cobalt layers on hardmetal articles during sintering

Konyashin, I.; Hlawatschek, S.; Ries, B.; Lachmann, F.; Vukovic, M.

doi:10.1016/j.ijrmhm.2013.08.016

Cited by 20 publications

(13 citation statements)

References 3 publications

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“…In those studies, increasing the surface area of particles depending on the decrease of particle sizes ensured that tungsten carbide materials have higher densities (85%) at high-temperature processes (<800 ∘ C). An increase in the carbide amount during the sintering of WC particles has a negative impact on the abrasion resistance of the resulting material [15]. In that study, the concentration of the tungsten carbide materials is 10% maximum and abrasion resistance is measured up to 1000 kg vertical load.…”

Section: Introductionmentioning

confidence: 87%

“…Therefore, synthesis and sintering of WC particles have been adopted in several industries such as metal and building industries that use high temperature (>1500 ∘ C) and corrosion (95% salt spray conditions) and abrasive conditions (6000 revolutions at a load of 13.6 kg using a 229 mm diameter rubber wheel and dry sand) [10][11][12]. It is convenient to use WC particles with sizes in the nanometer range (<10 m) in industrial processes such as metal industries [13][14][15]. Sintering below 500 ∘ C for 24 h can 2 Advances in Materials Science and Engineering afford WC particles that have a maximum particle size of 0.2 m as pointed out by Canakci et al and Joo et al [16,17].…”

Section: Introductionmentioning

confidence: 99%

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Effects of Mechanical Alloying on Sintering Behavior of Tungsten Carbide-Cobalt Hard Metal System

Gezerman

Çorbacıoğlu

2017

Advances in Materials Science and Engineering

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During the last few years, efforts have been made to improve the properties of tungsten carbides (WCs) by preparing composite materials. In this study, we prepared WC particles by mechanical alloying and investigated the effects of mechanical alloying conditions, such as mechanical alloying time and mechanically alloyed powder ratio, on the properties of 94WC-6Co. According to experimental studies, increasing the mechanical alloying time causes an increase in the density of tungsten carbide samples and a decrease of crystal sizes and inner strength of the prepared materials. With the increase of mechanical alloying time, fine particle concentrations of tungsten carbide samples have increased. It is observed that increasing the mechanical alloying time caused a decrease of the particle surface area of tungsten carbide samples. Besides, the amount of specific phases such as Co 3 W 3 C and Co 6 W 6 C increases with increasing mechanical alloying time. As another subject of this study, increasing the concentration of mechanically alloyed tungsten carbides caused an increase in the densities of final tungsten carbide materials. With the concentrations of mechanically alloyed materials, the occurrence of Co 6 W 6 C and Co 3 W 3 C phases and the increase of crystallization are observed.

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Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Effects of Mechanical Alloying on Sintering Behavior of Tungsten Carbide-Cobalt Hard Metal System

Gezerman

Çorbacıoğlu

2017

Advances in Materials Science and Engineering

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“…Cobalt capping was a term that refers to local thin layers of cobalt which were occasionally observed on the surface of sintered WC-Co parts when they came out of the furnace. Cobalt capping, which is usually believed undesirable and needs to be removed, was also considered to be related to the carbon atmosphere in the sintering furnace during cooling [76][77][78][79][80].…”

Section: Bulk Densification Techniquesmentioning

confidence: 99%

Development of manufacturing technology on WC–Co hardmetals

Nie

Zhang

2019

Tungsten

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Hardmetals are tungsten carbide (WC)-based composites, which are made of WC as a hard phase and transition metals such as Co, Fe, or/and Ni as ductile binder matrices. Their properties can be mainly tailored through the grain sizes of the sintered carbides and the amount of metallic binder. As successful tool materials, hardmetals are widely applied in metal cutting, wear applications, chipless forming, stoneworking, wood, and plastic working. In 2017, about two-thirds of tungsten consumption (including recycled materials) were produced for hardmetals in the world. This paper briefly introduces the development of manufacturing technology on WC-Co hardmetals from three aspects: powder preparation, bulk densification, and performance characterization. Two special WC-Co hardmetals are also described: cobalt-enrichment zone (CEZ) hardmetals, and binderless hardmetals. Furthermore, the development prospects for manufacturing techniques of hardmetals are also presented in the end. Keywords Hardmetal • Ultrafine WC powder • Ultrafine cobalt powder • Extrusion press • Liquid sintering • Cobaltenrichment zone hardmetal • Binderless hardmetal 2 Powder preparation techniques Although WC-Co hardmetals can be made directly with mixing and reactive sintering of tungsten, carbon, and cobalt powders [6], the most commonly used method for preparing Tungsten www.springer.com/42864

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“…Reasons for the presence or absence of Co layers on the surface of carbide articles after sintering have been a riddle up to recent times when the mechanism of the Co layers formation was established in refs. [51,52]. Sometimes such layers are present on the surface of carbide articles after sintering, however, in many cases when articles of the same carbide grade is repeatedly sintered in the same production sinter-HIP furnace there are no such layers on the carbide surface.…”

Section: Creating Co Gradients Due To Varying a Carbon Content In Dif...mentioning

confidence: 99%

Sintering Mechanisms of Functionally Graded Cemented Carbides

Konyashin

Lengauer

2016

MSF

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Functionally graded cemented carbides of two types are described. The functionally graded cemented carbides of the first type are of the WC-Co system and comprise gradients of WC grain sizes and/or Co contents. The functionally graded cemented carbides of the second type are Ti-and N-containing cemented carbides comprising gradients of nitrogen, cobalt and Ti-based cubic carbides. Special features and applications of the functionally graded cemented carbides of the both types are presented. Sintering mechanisms explaining the gradient formation in the functionally graded cemented carbides of the both types are summarized.

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Cobalt capping on WC–Co hardmetals. Part I: A mechanism explaining the presence or absence of cobalt layers on hardmetal articles during sintering

Cited by 20 publications

References 3 publications

Effects of Mechanical Alloying on Sintering Behavior of Tungsten Carbide-Cobalt Hard Metal System

Effects of Mechanical Alloying on Sintering Behavior of Tungsten Carbide-Cobalt Hard Metal System

Development of manufacturing technology on WC–Co hardmetals

Sintering Mechanisms of Functionally Graded Cemented Carbides

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