In-situ synthesized ceramic such as TiC,Cr7C3 and Cr5B3 reinforced Ni-based alloy composite coating was fabricated on the surface of mild steel substrate by reactive braze coating processing with colloidal graphite,Cr...In-situ synthesized ceramic such as TiC,Cr7C3 and Cr5B3 reinforced Ni-based alloy composite coating was fabricated on the surface of mild steel substrate by reactive braze coating processing with colloidal graphite,Cr,Ni,ferro-boron,Si and titanium powders as the raw materials at low temperature of 1000℃,and a new kind of coating materials was developed.By means of SEM,EDS,XRD and surface hardness tester,the microstructures,phases,hardness and wear-resistance of the coating were analyzed,respectively.The results revealed that the coating was mainly composed of the ceramic in-situ synthesized reinforcement phases of TiC,Cr7C3 and Cr5B3 and the binder phases in-situ synthesized of Ni31Si12 and(Ni,Fe)solid solution;The ceramic reinforcement phases of TiC,Cr7C3 and Cr5B3 were randomly distributed in the binder phases of Ni31Si12 and(Ni,Fe)solid solution;The coating had about 15vol%pores and can possibly be applied as a self-lubrication coating;The coating and the substrate were integrated together by metallurgical bonding;The coating had a hardness up to 91-94HR15N.展开更多
WC7Co/Ti6Al4V composite coatings are deposited on the pure Ti substrate by pulse laser cladding(LC).During the laser melting process,the decomposition of WC7Co particles will lead to the evolution of microstructure an...WC7Co/Ti6Al4V composite coatings are deposited on the pure Ti substrate by pulse laser cladding(LC).During the laser melting process,the decomposition of WC7Co particles will lead to the evolution of microstructure and phases,which is directly related to the wear resistance and mechanism of composite coating.The microstructural evolution,phase compositions and interface reaction of WC7Co/Ti6Al4V composite coating were examined by scanning electron microscopy,energydispersive spectrum and X-ray diffraction(XRD).The hardness of different structures and abrasive resistance of composite coating were measured.The results show that the typical microstructure of LC WC7Co/Ti6Al4V composite coating can be classified into dissolved WC7Co composite structure and un-dissolved WC7Co structure.According to XRD results,there are Ti solid solution,W,TiC,VC,Co3W3C and secondary W2C in composite coating.The eutectic structure formed by the dissolved WC7Co particles consisted of W,W2C,TiC and P-Ti solid solution.The mean hardness of different structures exhibits a significant gradient distribution in composite coating.A reaction layer composed of TiC,W and W2C is also generated onto the interface between un-dissolved WC7Co particles and Ti6Al4V alloy matrix.The abrasive mechanisms of WC7Co/Ti6Al4V composite coating are mainly adhesive wear and oxidation wear during the dry sliding process.展开更多
基金supported by Yangjiang science and technology project (0202010067)Yangjiang polytechnic for providing financial assistance.
文摘In-situ synthesized ceramic such as TiC,Cr7C3 and Cr5B3 reinforced Ni-based alloy composite coating was fabricated on the surface of mild steel substrate by reactive braze coating processing with colloidal graphite,Cr,Ni,ferro-boron,Si and titanium powders as the raw materials at low temperature of 1000℃,and a new kind of coating materials was developed.By means of SEM,EDS,XRD and surface hardness tester,the microstructures,phases,hardness and wear-resistance of the coating were analyzed,respectively.The results revealed that the coating was mainly composed of the ceramic in-situ synthesized reinforcement phases of TiC,Cr7C3 and Cr5B3 and the binder phases in-situ synthesized of Ni31Si12 and(Ni,Fe)solid solution;The ceramic reinforcement phases of TiC,Cr7C3 and Cr5B3 were randomly distributed in the binder phases of Ni31Si12 and(Ni,Fe)solid solution;The coating had about 15vol%pores and can possibly be applied as a self-lubrication coating;The coating and the substrate were integrated together by metallurgical bonding;The coating had a hardness up to 91-94HR15N.
基金National Natural Science Foundation of China(51701165)the Natural Science Foundation of Shaanxi Province(2018JM5005)+1 种基金Postdoctoral Science Foundation of China(2017M623334XB)Shaanxi Province Postdoctoral Science Foundation(2018BSHQYXMZZ36).
文摘WC7Co/Ti6Al4V composite coatings are deposited on the pure Ti substrate by pulse laser cladding(LC).During the laser melting process,the decomposition of WC7Co particles will lead to the evolution of microstructure and phases,which is directly related to the wear resistance and mechanism of composite coating.The microstructural evolution,phase compositions and interface reaction of WC7Co/Ti6Al4V composite coating were examined by scanning electron microscopy,energydispersive spectrum and X-ray diffraction(XRD).The hardness of different structures and abrasive resistance of composite coating were measured.The results show that the typical microstructure of LC WC7Co/Ti6Al4V composite coating can be classified into dissolved WC7Co composite structure and un-dissolved WC7Co structure.According to XRD results,there are Ti solid solution,W,TiC,VC,Co3W3C and secondary W2C in composite coating.The eutectic structure formed by the dissolved WC7Co particles consisted of W,W2C,TiC and P-Ti solid solution.The mean hardness of different structures exhibits a significant gradient distribution in composite coating.A reaction layer composed of TiC,W and W2C is also generated onto the interface between un-dissolved WC7Co particles and Ti6Al4V alloy matrix.The abrasive mechanisms of WC7Co/Ti6Al4V composite coating are mainly adhesive wear and oxidation wear during the dry sliding process.
