Ni-CNT (carbon nanotube) composite coatings were processed by electrodeposition and their hardness and corrosion characteristics were investigated with variations of CNT concentration in an electrolyte solution and el...Ni-CNT (carbon nanotube) composite coatings were processed by electrodeposition and their hardness and corrosion characteristics were investigated with variations of CNT concentration in an electrolyte solution and electrodeposition current density. With increasing the CNT concentration in the electrodeposition bath and the current density, more CNTs are incorporated into Ni matrix. Hardness values of the Ni-CNT coatings are irrelevant to the CNT concentration in the solution, the current density, and current mode, implying poor adhesion of CNTs to Ni matrix. With increasing the CNT content in the coating, the corrosion resistance of the Ni-CNT composite coating becomes inferior due to the porous microstructure.展开更多
The corrosion behavior of B30 Cu-Ni alloy in a sterile seawater and a SRB solution was investigated. The results show that the corrosion potential of specimen in the SRB solution is much lower than that in the sterile...The corrosion behavior of B30 Cu-Ni alloy in a sterile seawater and a SRB solution was investigated. The results show that the corrosion potential of specimen in the SRB solution is much lower than that in the sterile seawater. The polarization resistance of specimen in the SRB solution decreases quickly after a period immersion and becomes much lower than that in the sterile seawater. It is concluded that the SRB accelerates the corrosion process of B30 Cu-Ni alloy greatly. An anti-corrosion electroless Ni-P coating was produced and applied to the alloy. The results show that specimens coated with Ni-P plating exhibit favorable corrosion resistance property in SRB solution. Severe pitting corrosion appears on the uncoated specimens in the SRB solution when the coated specimens are still in good condition. The anti-corrosion mechanism of Ni-P plating was analyzed. It is concluded that coating the B30 Cu-Ni alloy with electroless Ni-P plating is an effective technique against the attack of SRB in marine environment.展开更多
The corrosion and high-temperature oxidation characteristics of AM60 Mg alloy in different environments were investigated by immersion test,electrochemical polarizing analysis and differential thermal analysis(DTA)/th...The corrosion and high-temperature oxidation characteristics of AM60 Mg alloy in different environments were investigated by immersion test,electrochemical polarizing analysis and differential thermal analysis(DTA)/thermo gravimetric(TG) experiments. The influence of aging heat treatment on the corrosion resistance of AM60 Mg alloy was studied. AM60 Mg alloy shows better corrosion resistance in sea water than in 3.5%(mass fraction) NaCl solution. The corrosion resistance after aging for 24 h is better than that of both as-cast and aging for 48 h. Corrosion resistance of Mg alloy is controled by microstructure,composition of α-matrix. Precipitation of β phase along the grain boundaries acts as a barrier that decreases corrosion rate,whereas the decrease of aluminum content of α phase causes an increase in the corrosion rate. The DTA and TG curves of heating process in air are characterized with combustion after 590 ℃. When heated in helium,the curves show two endothermic peaks and a remarkable evaporation of magnesium. As for isothermal DTA and TG experiments,mass increment caused by oxidation does not happen till 520 ℃.展开更多
基金supported by the Center for Electronic Packaging Materials of Korea Science Engineering Foundation
文摘Ni-CNT (carbon nanotube) composite coatings were processed by electrodeposition and their hardness and corrosion characteristics were investigated with variations of CNT concentration in an electrolyte solution and electrodeposition current density. With increasing the CNT concentration in the electrodeposition bath and the current density, more CNTs are incorporated into Ni matrix. Hardness values of the Ni-CNT coatings are irrelevant to the CNT concentration in the solution, the current density, and current mode, implying poor adhesion of CNTs to Ni matrix. With increasing the CNT content in the coating, the corrosion resistance of the Ni-CNT composite coating becomes inferior due to the porous microstructure.
基金Project (2005JS5144904.01) supported by the State Key Laboratory for Marine Corrosion and Protection, China
文摘The corrosion behavior of B30 Cu-Ni alloy in a sterile seawater and a SRB solution was investigated. The results show that the corrosion potential of specimen in the SRB solution is much lower than that in the sterile seawater. The polarization resistance of specimen in the SRB solution decreases quickly after a period immersion and becomes much lower than that in the sterile seawater. It is concluded that the SRB accelerates the corrosion process of B30 Cu-Ni alloy greatly. An anti-corrosion electroless Ni-P coating was produced and applied to the alloy. The results show that specimens coated with Ni-P plating exhibit favorable corrosion resistance property in SRB solution. Severe pitting corrosion appears on the uncoated specimens in the SRB solution when the coated specimens are still in good condition. The anti-corrosion mechanism of Ni-P plating was analyzed. It is concluded that coating the B30 Cu-Ni alloy with electroless Ni-P plating is an effective technique against the attack of SRB in marine environment.
基金Project (JSAWT-06-08) supported by the Key Laboratory of Advanced Welding Technology of Jiangsu Province, China
文摘The corrosion and high-temperature oxidation characteristics of AM60 Mg alloy in different environments were investigated by immersion test,electrochemical polarizing analysis and differential thermal analysis(DTA)/thermo gravimetric(TG) experiments. The influence of aging heat treatment on the corrosion resistance of AM60 Mg alloy was studied. AM60 Mg alloy shows better corrosion resistance in sea water than in 3.5%(mass fraction) NaCl solution. The corrosion resistance after aging for 24 h is better than that of both as-cast and aging for 48 h. Corrosion resistance of Mg alloy is controled by microstructure,composition of α-matrix. Precipitation of β phase along the grain boundaries acts as a barrier that decreases corrosion rate,whereas the decrease of aluminum content of α phase causes an increase in the corrosion rate. The DTA and TG curves of heating process in air are characterized with combustion after 590 ℃. When heated in helium,the curves show two endothermic peaks and a remarkable evaporation of magnesium. As for isothermal DTA and TG experiments,mass increment caused by oxidation does not happen till 520 ℃.
