A solid state synthesis of ultrafine/nanocrystalline WC-10Co composite powders was reported from WO3 , Co3O4 and carbon powders after reduction and carburization at relatively low temperatures in a short time under pu...A solid state synthesis of ultrafine/nanocrystalline WC-10Co composite powders was reported from WO3 , Co3O4 and carbon powders after reduction and carburization at relatively low temperatures in a short time under pure H2 atmosphere. The effects of ball milling time and reaction temperature on the preparation of ultrafine/nanocrystalline WC-Co composite powders were studied using X-ray diffraction and scanning electron microscope (SEM). The results show that fine mixed oxide powders (WO3 , Co3O4 and carbon powders) can be obtained by long time ball milling. Increasing the reaction temperature can decrease the formation of Co3W3C and graphite phases and increase the WC crystallite size. Long-time ball milling and high reaction temperature are favorable to obtain fine and pure composite powders consisting of nanocrystalline WC from WO3 , Co3O4 and carbon powders.展开更多
A new process of WC-Co cemented carbide was developed by using nano-grained W（Co, C） composite powders as raw materials processed by high-energy ball milling. X-ray diffraetion（XRD）, differential thermal analysis ...A new process of WC-Co cemented carbide was developed by using nano-grained W（Co, C） composite powders as raw materials processed by high-energy ball milling. X-ray diffraetion（XRD）, differential thermal analysis （DTA）, thermo-gravimetrie （TG） analysis and coercive forces of the sintered samples were adopted to analyze the phase transformation and constitution, and the microstructures of sintered samples were characterized by scanning electron microscopy（SEM）. The results show that the as-milled powders are transformed into transitional phases W2C and η （Co3W3C or Co6W6C） during sintering, and finally transformed into WC and Co phases completely at 1 250℃ for 30 min, and a large number of fibrous WC grains with about 1.2μm in length and 100 nm in radial dimension are formed in the sintered body at 1 300 ℃.展开更多
基金Projects(50823006, 51021063, 51271152) supported by the National Natural Science Foundation of ChinaProject(NCET-10-0842)supported by the Program for New Century Excellent Talents in Universities of China
文摘A solid state synthesis of ultrafine/nanocrystalline WC-10Co composite powders was reported from WO3 , Co3O4 and carbon powders after reduction and carburization at relatively low temperatures in a short time under pure H2 atmosphere. The effects of ball milling time and reaction temperature on the preparation of ultrafine/nanocrystalline WC-Co composite powders were studied using X-ray diffraction and scanning electron microscope (SEM). The results show that fine mixed oxide powders (WO3 , Co3O4 and carbon powders) can be obtained by long time ball milling. Increasing the reaction temperature can decrease the formation of Co3W3C and graphite phases and increase the WC crystallite size. Long-time ball milling and high reaction temperature are favorable to obtain fine and pure composite powders consisting of nanocrystalline WC from WO3 , Co3O4 and carbon powders.
基金Project (50474049) supported by the National Natural Science Foundation of China
文摘A new process of WC-Co cemented carbide was developed by using nano-grained W（Co, C） composite powders as raw materials processed by high-energy ball milling. X-ray diffraetion（XRD）, differential thermal analysis （DTA）, thermo-gravimetrie （TG） analysis and coercive forces of the sintered samples were adopted to analyze the phase transformation and constitution, and the microstructures of sintered samples were characterized by scanning electron microscopy（SEM）. The results show that the as-milled powders are transformed into transitional phases W2C and η （Co3W3C or Co6W6C） during sintering, and finally transformed into WC and Co phases completely at 1 250℃ for 30 min, and a large number of fibrous WC grains with about 1.2μm in length and 100 nm in radial dimension are formed in the sintered body at 1 300 ℃.
