Search

For improving the wear resistance and corrosion resistance of 38CrMoAl steel substrate， CoMoCrNi alloy powder was used as the research object to be mixed with a special binder and coated on the surface of 38CrMoAl steel substrate，and subsequently，the CoMoCrNi coating was prepared by vacuum cladding.The structure and comprehensive performance of the coating were investigated through XRD， SEM and its accompanying EDS instrument， hardness test， abrasive wear test， acidic salt spray test and electrochemical corrosion test.Results showed that the as-prepared CoMoCrNi coating had the smooth surface with metallic luster.The coating was composed of Co-based solid solution and Co3Mo2Si hard Laves phase， and the structure was fine， uniform and dense.In addition， a strong metallurgical bond was formed between the CoMoCrNi coating and the substrate.The micro-Vickers hardness of the substrate/coating exhibited a gradient distribution pattern， and there were dispersed hard phases in the coating，which had a much higher microhardness than the substrate.The wear resistance and corrosion resistance of CoMoCrNi coating were higher than those of the base material.Furthermore， compared with the self-fluxing cobalt-based alloy coatings prepared by current mainstream surface processing technologies such as laser cladding and surfacing welding， the CoMoCrNi coating prepared by the vacuum cladding method showed better wear resistance and corrosion resistance.In general， the coating possessed a stronger comprehensive load-bearing capacity， which could be expected to be used in complex working conditions.

In order to enhance the service life of special complex shaped workpieces under severe working conditions, a new coating preparation process, namely, easy-coating and sintering technology, has been proposed. In this study, the feasibility of preparing Co-based coatings on 38CrMoAl substrates using the easy-coating and sintering process was investigated, and the microstructure and properties of the Co-based coatings were studied. By optimizing the parameters of the sintering process, the prepared coating is dense, and the coating forms a good metallurgical bond with the substrate with few pores, but no other defects. As the process has good applicability to the surface of complex-shaped parts, the inner wall of small serpentine tubes and large thicknesses, and is low-cost and easy to operate, the easy-coating-sintering process has great application prospects.

Objective: To develop a HCV combined HBV DNA-based therapeutic vaccine., Methods: The HBV core gene and HCV core cDNA were inserted into the eukaryotic expression vector with two multiple cloning sites mammalian expression vector, which can be used for expression of two foreign genes, under the CMV promoter and RSC promoter respectively (named pRSC-HBV/HCV). Cellular expression of pRSC-HBV/HCV was assessed following transfection into SP2/0 cells. The Balb/c mice were immunized by multiple sites intramuscular injection with pRSC-HBV/HCV and the immune responses were detected., Results: The 21-kd and 14-kd core protein was observed. Both anti-HBc IgG and anti-HCV core Ab were detected in all immunized mice. Strong CTL activity of splenocytes against SP2/0 cells expressing both HBV and HCV core proteins were measured in immunized mice both in vitro and in vivo., Conclusion: The investigation demonstrated that pRSC-HBV/HCV could generated both humoral immune response and Strong CTL activity against HBcAg and HCV nucleocapsid in mice.