PbO-ZnO-Na2O ceramic coating was fabricated on the AZ91D Mg-alloy substrate surface by using of evaporated pattern casting(EPC) process.The ceramic coating was characterized through scanning electron microscopy(SEM) o...PbO-ZnO-Na2O ceramic coating was fabricated on the AZ91D Mg-alloy substrate surface by using of evaporated pattern casting(EPC) process.The ceramic coating was characterized through scanning electron microscopy(SEM) observation,energy dispersive X-ray spectrometer(EDS) and so on.The research was emphasized on the formation process of ceramic coating and the interface bonding conditions between ceramic coating and the substrate.Results show that the glass powder(PbO-ZnO-Na2O) melts when contacts with the high temperature liquid metal,and solidifies on the surface of the substrate with the decrease of temperature.Therefore,the ceramic coating was successfully prepared with the formation of the bonding interface with the substrate.Beside the influence of coating layer thickness,the vacuum level was also investigated.Further analysis indicates that oxide inclusions and decomposition products of foam pattern had a significant effect on the bonding interface.To obtain a good bonding interface between the ceramic coating and the substrate,the metal liquid oxidation and inclusions must be decreased and the decomposition products of foam pattern should be exhausted from the EPC coating completely.展开更多
The influencing factors of surface alloying layer by evaporative pattern casting technology were investigated.A certain thickness alloying layer was formed on the surface of Mg-alloy matrix when the pouring temperatur...The influencing factors of surface alloying layer by evaporative pattern casting technology were investigated.A certain thickness alloying layer was formed on the surface of Mg-alloy matrix when the pouring temperature was 780°C with different vacuum degree and alloying powder size.The surface layer microstructure,micro area composition of the new phase formed on the matrix and the composition characteristics on the surface layer were examined by SEM and element scanning.The results show that the content of aluminum increases greatly on the surface layer.The micro-hardness of alloyed layer has a more obvious increase compared with that of the matrix.The size of alloying element and the vacuum degree are the key factors influencing the alloying layer,with the increase of element powder size from 0.074 to 0.15 mm and vacuum degree from 0.04 to 0.06 MPa,the surface alloying effect becomes better.展开更多
In this paper the Expendable Pattern Casting with dry sand Vacuum(EPC-V) process is used to manufacture iron matrix composites with tungsten carbide particle.Microstructures of the composites layers were analyzed.The ...In this paper the Expendable Pattern Casting with dry sand Vacuum(EPC-V) process is used to manufacture iron matrix composites with tungsten carbide particle.Microstructures of the composites layers were analyzed.The abrasive wear resistance of the composites layers were tested and compared with that of high chromium cast iron.The results show that the iron matrix composites with tungsten carbide particle have high hardness.The abrasive wear resistance of composites with tungsten carbide particle is higher than that of high chromium cast iron.The properties of the matrix materials have been improved remarkably.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.50775085)
文摘PbO-ZnO-Na2O ceramic coating was fabricated on the AZ91D Mg-alloy substrate surface by using of evaporated pattern casting(EPC) process.The ceramic coating was characterized through scanning electron microscopy(SEM) observation,energy dispersive X-ray spectrometer(EDS) and so on.The research was emphasized on the formation process of ceramic coating and the interface bonding conditions between ceramic coating and the substrate.Results show that the glass powder(PbO-ZnO-Na2O) melts when contacts with the high temperature liquid metal,and solidifies on the surface of the substrate with the decrease of temperature.Therefore,the ceramic coating was successfully prepared with the formation of the bonding interface with the substrate.Beside the influence of coating layer thickness,the vacuum level was also investigated.Further analysis indicates that oxide inclusions and decomposition products of foam pattern had a significant effect on the bonding interface.To obtain a good bonding interface between the ceramic coating and the substrate,the metal liquid oxidation and inclusions must be decreased and the decomposition products of foam pattern should be exhausted from the EPC coating completely.
基金Project(50775085)supported by the National Natural Science Foundation of China
文摘The influencing factors of surface alloying layer by evaporative pattern casting technology were investigated.A certain thickness alloying layer was formed on the surface of Mg-alloy matrix when the pouring temperature was 780°C with different vacuum degree and alloying powder size.The surface layer microstructure,micro area composition of the new phase formed on the matrix and the composition characteristics on the surface layer were examined by SEM and element scanning.The results show that the content of aluminum increases greatly on the surface layer.The micro-hardness of alloyed layer has a more obvious increase compared with that of the matrix.The size of alloying element and the vacuum degree are the key factors influencing the alloying layer,with the increase of element powder size from 0.074 to 0.15 mm and vacuum degree from 0.04 to 0.06 MPa,the surface alloying effect becomes better.
文摘In this paper the Expendable Pattern Casting with dry sand Vacuum(EPC-V) process is used to manufacture iron matrix composites with tungsten carbide particle.Microstructures of the composites layers were analyzed.The abrasive wear resistance of the composites layers were tested and compared with that of high chromium cast iron.The results show that the iron matrix composites with tungsten carbide particle have high hardness.The abrasive wear resistance of composites with tungsten carbide particle is higher than that of high chromium cast iron.The properties of the matrix materials have been improved remarkably.
