Sergei Letunovitš - Academia.edu (original) (raw)
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Central Research Institute for Dryland Agriculture
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Papers by Sergei Letunovitš
International Journal of Materials and Product Technology, 2011
... Biographical notes: Kristjan Juhani is a PhD student in the Department of Materials Engineeri... more ... Biographical notes: Kristjan Juhani is a PhD student in the Department of Materials Engineering, Tallinn University of Technology ... There are several studies about manufacturing chromium carbide by high energy milling (Li and Tang, 1994; Huang and McCormick, 1997; Pirso et ...
Estonian Journal of Engineering
A novel recycling technology for the production of bulk WC-Co hardmetals from a mixture of WO3, C... more A novel recycling technology for the production of bulk WC-Co hardmetals from a mixture of WO3, CoWO4 and graphite powders by way of carbothermal reduction in combination with reactive sintering has been developed. Waste hardmetals parts with 15 wt% Co from hardmetals production were fully oxidized into a mixture of WO3 and CoWO4 powder. To oxide powder mixtures, carbon was added in the form of nanocrystalline graphite, milled, pressed into compacts and sintered. During reactive sintering carbothermal reduction, tungsten monocarbide (WC) synthesis and structure formation occurs in one cycle. The influence of different graphite content in the initial powder mixtures on the phase composition, and linear shrinkage during solid and liquid state sintering is discussed. The microstructure of reactive sintered WC-Co composites is fine-grained and identical to that of the original WC-Co microstructure and has similar mechanical properties.
Wear, 2007
This paper is on comparison of the abrasive and erosive wear resistance of chromium carbide based... more This paper is on comparison of the abrasive and erosive wear resistance of chromium carbide based and nickel bonded cermets prepared by two different methods: conventional powder metallurgy sintering and the new developed one-reactive carburizing sintering. The nickel content was varied at the weight percents of 10, 20 and 30%. Results indicate that sintering process and microstructural parameters influence materials resistance to erosion and abrasion. It is shown, that cermets produced by reactive carburizing sintering have some advantage in erosion and abrasion resistance over conventionally produced ones.
International Journal of Materials and Product Technology, 2011
... Biographical notes: Kristjan Juhani is a PhD student in the Department of Materials Engineeri... more ... Biographical notes: Kristjan Juhani is a PhD student in the Department of Materials Engineering, Tallinn University of Technology ... There are several studies about manufacturing chromium carbide by high energy milling (Li and Tang, 1994; Huang and McCormick, 1997; Pirso et ...
Estonian Journal of Engineering
A novel recycling technology for the production of bulk WC-Co hardmetals from a mixture of WO3, C... more A novel recycling technology for the production of bulk WC-Co hardmetals from a mixture of WO3, CoWO4 and graphite powders by way of carbothermal reduction in combination with reactive sintering has been developed. Waste hardmetals parts with 15 wt% Co from hardmetals production were fully oxidized into a mixture of WO3 and CoWO4 powder. To oxide powder mixtures, carbon was added in the form of nanocrystalline graphite, milled, pressed into compacts and sintered. During reactive sintering carbothermal reduction, tungsten monocarbide (WC) synthesis and structure formation occurs in one cycle. The influence of different graphite content in the initial powder mixtures on the phase composition, and linear shrinkage during solid and liquid state sintering is discussed. The microstructure of reactive sintered WC-Co composites is fine-grained and identical to that of the original WC-Co microstructure and has similar mechanical properties.
Wear, 2007
This paper is on comparison of the abrasive and erosive wear resistance of chromium carbide based... more This paper is on comparison of the abrasive and erosive wear resistance of chromium carbide based and nickel bonded cermets prepared by two different methods: conventional powder metallurgy sintering and the new developed one-reactive carburizing sintering. The nickel content was varied at the weight percents of 10, 20 and 30%. Results indicate that sintering process and microstructural parameters influence materials resistance to erosion and abrasion. It is shown, that cermets produced by reactive carburizing sintering have some advantage in erosion and abrasion resistance over conventionally produced ones.