Papers by Keyword: WC-17Co

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Authors: Guo Qing Gou, Nan Huang, Hui Chen, Da Li, Yan Liu, Hua Ji, Yong Hui Zhu, Gui Guo Wang, Jin Peng Yu
Abstract: Nanostructured WC-17Co coating was prepared by means of High Velocity Oxygen Flame (HVOF) technique. Characteristic of nano-structure of the coating was analyzed. The coating seems to be of lamination structure formed by fully or partially melted powder. It shows that the coating consists of melted and recrystallized zone, semi-molten zone and un-melted zone. Amorphous phase and nanocrystalline phase co-existed in the coating is due to the rapid heating and cooling during spraying. The nanostructured coating possesses excellent mechanical properties, which are closely related to the unique nanostructures existed in the coating.
Authors: Guo Qing Gou, Nan Huang, Hui Chen, Da Li, Yan Liu, Hua Ji
Abstract: Nanostructured WC-17Co coatings, nanostructured WC-12Co coatings, conventional WC-17Co coatings were prepared by means of High Velocity Oxygen Flame (HVOF) technique. The characteristic of powders and coatings of nanostructured WC-17Co coatings, hardness of different coatings, distribution gradient of the hardness of the nanostructured WC-17Co coatings in the depth direction, fracture toughness and interface fracture toughness of different coatings, residual stress of different coatings, different phase and distribution of WC phase in the depth direction were investigated. The results indicated that the micro-crack is spread along the phase interface where the brittle phase are more in the Co rich area , where there are more different properties in the Co rich area and W rich area, where there are more defects close to the intend end in the W rich area, even spread through the WC particles in microcosmic and the different residual stress of different phase are because of different melting point and different expansion coefficient , so the WC, W2C produced compressed stress, the Co6W6C produced tensile stress. The residual stress manifested from higher to lower in the depth direction of the coatings.
Authors: Guo Qing Gou, Da Li, Nan Huang, Yan Liu, Hui Chen, Li Chun Meng
Abstract: Nanostructured WC-17Co coating was prepared by means of High Velocity Oxygen Flame (HVOF) technique. When eroded with quartz sand, the erosion wear resistance of nanostructured coating is better than that of 1Cr13. The loss of Co-rich phase dominates the main failure mechanism, following with minor peeling of WC particles.
Authors: Shahin Khameneh Asl, M. Heydarzadeh Sohi, Kazuyuki Hokamoto, Mitsuhiro Matsuda, Ryuichi Tomoshige, Minoru Nishida
Abstract: In this work, WC-17Co powder was thermally sprayed onto mild steel using HVOF spray technique. The coated specimen was heat treated at 1100°C in a vacuum chamber and was then studied by using transmission electron microscopy (TEM). Post heat treatment resulted in recrystallization of the amorphous phase, formed during thermal spraying, into low carbon eta phase like Co6W6C. TEM results of the heat treated specimens showed that these new nucleated eta phases had very clear crystallographic structure without any crystalline defects. Heat treatment could also transform high carbon carbides like WC and W2C in the as sprayed samples to high carbon eta phases like Co3W3C. High density of dislocations and staking faults noticed in TEM of these phases might be an indication of possible shear mechanism in formation of these carbides.
Authors: Shahin Khameneh Asl, M. Heydarzadeh Sohi, S.M.M. Hadavi
Authors: Xu Wu, Zhi Meng Guo
Abstract: This work use the D-gun system to spray the WC-17Co coating. analyzed the microstructure and performance of the coating by SEM, EDAX, XRD, HAXD. It gave a basis for the next research work for the anti-wear coating on aluminum alloy. The hardness of the WC-17Co coating is about HV1100~1300, the average porosity less than 1%. And the max diameter of the single hole is less than 0.012mm. There are no apparent oxide in the coating. The WC particles occurred decarburization during the spraying process and deposited the coating that composed with W2C and Co3W3C phases. The corrosion resistance of the coating is more ideal. But the phase distribution in the coating is not enough uniform.
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