NiCoCrAlY/ZrO2 coatings were obtained by cold spraying.Nitrogen gas was used as processing gas(750℃,3.8 MPa).The corrosion electrochemical behavior of the coating on 907A steel in seawater was studied using open circ...NiCoCrAlY/ZrO2 coatings were obtained by cold spraying.Nitrogen gas was used as processing gas(750℃,3.8 MPa).The corrosion electrochemical behavior of the coating on 907A steel in seawater was studied using open circuit potential monitoring,potentio-dynamic polarization and electrochemical impedance spectroscopy.Results showed that the as-deposited NiCoCrAlY/ZrO2 coatings,which were formed through significantly plastic deformed particles during impact,presented a dense microstructure and a high hardness.Results indicated that the formation of the stable and consecutive oxidation film,which has an outstanding anti-corrosion performance,was contributed to the compact structure of cold spray coatings.The pervasion of seawater was held back resulting from the cooperation of the oxidation film and the scale-like structure.展开更多
The NiCoCrAlY coatings strengthened by three nano-particles with the same addition were prepared on a Ni-base super alloy using laser cladding technique. The dry frictional wear behaviors of the coatings at 500 ℃ in ...The NiCoCrAlY coatings strengthened by three nano-particles with the same addition were prepared on a Ni-base super alloy using laser cladding technique. The dry frictional wear behaviors of the coatings at 500 ℃ in static air were investigated. The comparison was made with the coating without nano-particles. The results show that the wear mechanism of the NiCoCrAlY coatings with nano-particles, like the coating without nano-particles, is the delamination wear due to the strong plastic deformation and oxidative wear. However, the frictional coefficient of the coatings increases and presents the decrease trend with the increase of sliding distance after adding nano-particles. Moreover, the wear rate of the coatings with nano-particles is only 34.0%-64.5% of the coating without nano-particles. Among the three nano-particles, the improvement of nano-SiC on the high temperature wear resistance of the coating is the most significant.展开更多
The high-temperature oxidation resistance behavior of 7% （mass fraction） Y203-ZrO2 thermal barrier coatings （TBCs） irradiated by high-intensity pulsed ion beam （HIPIB） was investigated under the cyclic oxidation...The high-temperature oxidation resistance behavior of 7% （mass fraction） Y203-ZrO2 thermal barrier coatings （TBCs） irradiated by high-intensity pulsed ion beam （HIPIB） was investigated under the cyclic oxidation condition of 1 050 ℃ and 1 h. The columnar grains in the TBCs disappear after the HIPIB irradiation at ion current densities of 100-200 A/cm^2 and the irradiated surface becomes smooth and densified after remelting and ablation due to the HIPIB irradiation. The thermally grown oxide （TGO） layer thickness of the irradiated TBCs is smaller than that of the original TBCs. After 15 cycles, the mass gains of the original TBCs and those irradiated by ion current densities of 100 and 200 A/cm^2 due to the oxidation are found to be 0.8-0.9, 0.6-0.7, and 0.3-0.4 mg/cm^2, respectively. The inward diffusion of oxygen through the irradiated TBCs is significantly impeded by the densified top layer formed due to irradiation, which is the main reason for the improved overall oxidation resistance of the irradiated TBCs.展开更多
Y2O3 stabilized ZrO2(YSZ)thermal barrier coatings(TBCs)are prone to hot corrosion by molten salts.In this study,the microstructure of atmospheric plasma spraying YSZ TBCs is modified by laser glazing in order to impro...Y2O3 stabilized ZrO2(YSZ)thermal barrier coatings(TBCs)are prone to hot corrosion by molten salts.In this study,the microstructure of atmospheric plasma spraying YSZ TBCs is modified by laser glazing in order to improve the corrosion resistance.By optimizing the laser parameters,a^18μm smooth glazed layer with some vertical cracks was produced on the coating surfaces.The as-sprayed and modified coatings were both exposed to hot corrosion tests at 700 and 1000℃for 4 h in V2O5 molten salt,and the results revealed that the modified one had improved corrosion resistance.After hot corrosion,the glazed layer kept structural integrity,with little evidence of dissolution.However,the vertical cracks in the glazed layer acted as the paths for molten salt penetration,accelerating the corrosion of the non-modified coating.Further optimization of the glazed layer is needed in the future work.展开更多
Preconcentration/separation of Co（II）, Fe（III）, Pb（II）, Cr（IIl）, Cu（II） and Cd（II） ions using bis（5-bromo- 2-hydroxy-benzaldehyde）-2-methy1-1,5-pentane diimine （BBHBPDI） on SDS coated alumina has been ...Preconcentration/separation of Co（II）, Fe（III）, Pb（II）, Cr（IIl）, Cu（II） and Cd（II） ions using bis（5-bromo- 2-hydroxy-benzaldehyde）-2-methy1-1,5-pentane diimine （BBHBPDI） on SDS coated alumina has been reported. The influences of the analytical parameters including pH, ligand and SDS amount, type and concentration of eluent and sample volume on metal ions recoveries were investigated. At optimum values of all variables the relative standard deviation are between 2.5-2.7 and preconcentration factor was 375, while recoveries for all understudy metal ions are higher than 95%, determination limits are between 1.5-2.7. The method has been successfully applied to determination of Co（II）, Fe（III）, Pb（II）, Cr（III）, Cu（II） and Cd（II） ions content in some real samples.展开更多
文摘NiCoCrAlY/ZrO2 coatings were obtained by cold spraying.Nitrogen gas was used as processing gas(750℃,3.8 MPa).The corrosion electrochemical behavior of the coating on 907A steel in seawater was studied using open circuit potential monitoring,potentio-dynamic polarization and electrochemical impedance spectroscopy.Results showed that the as-deposited NiCoCrAlY/ZrO2 coatings,which were formed through significantly plastic deformed particles during impact,presented a dense microstructure and a high hardness.Results indicated that the formation of the stable and consecutive oxidation film,which has an outstanding anti-corrosion performance,was contributed to the compact structure of cold spray coatings.The pervasion of seawater was held back resulting from the cooperation of the oxidation film and the scale-like structure.
基金Project(20060287019)supported by the Research Fund for Doctoral Program of Higher Education of ChinaProject(kjsmcx07001)supported by the Opening Research Fund of Jiangsu Key Laboratory of Tribology,ChinaProject(BK2010267)supported by the Jiangsu Provincial Natural Science Foundation of Jiangsu Province,China
文摘The NiCoCrAlY coatings strengthened by three nano-particles with the same addition were prepared on a Ni-base super alloy using laser cladding technique. The dry frictional wear behaviors of the coatings at 500 ℃ in static air were investigated. The comparison was made with the coating without nano-particles. The results show that the wear mechanism of the NiCoCrAlY coatings with nano-particles, like the coating without nano-particles, is the delamination wear due to the strong plastic deformation and oxidative wear. However, the frictional coefficient of the coatings increases and presents the decrease trend with the increase of sliding distance after adding nano-particles. Moreover, the wear rate of the coatings with nano-particles is only 34.0%-64.5% of the coating without nano-particles. Among the three nano-particles, the improvement of nano-SiC on the high temperature wear resistance of the coating is the most significant.
基金Projects supported by The 2nd Stage of Brain Korea and Korea Research Foundation
文摘The high-temperature oxidation resistance behavior of 7% （mass fraction） Y203-ZrO2 thermal barrier coatings （TBCs） irradiated by high-intensity pulsed ion beam （HIPIB） was investigated under the cyclic oxidation condition of 1 050 ℃ and 1 h. The columnar grains in the TBCs disappear after the HIPIB irradiation at ion current densities of 100-200 A/cm^2 and the irradiated surface becomes smooth and densified after remelting and ablation due to the HIPIB irradiation. The thermally grown oxide （TGO） layer thickness of the irradiated TBCs is smaller than that of the original TBCs. After 15 cycles, the mass gains of the original TBCs and those irradiated by ion current densities of 100 and 200 A/cm^2 due to the oxidation are found to be 0.8-0.9, 0.6-0.7, and 0.3-0.4 mg/cm^2, respectively. The inward diffusion of oxygen through the irradiated TBCs is significantly impeded by the densified top layer formed due to irradiation, which is the main reason for the improved overall oxidation resistance of the irradiated TBCs.
基金This research is sponsored by the National Natural Science Foundation of China(Grant No.51971156).
文摘Y2O3 stabilized ZrO2(YSZ)thermal barrier coatings(TBCs)are prone to hot corrosion by molten salts.In this study,the microstructure of atmospheric plasma spraying YSZ TBCs is modified by laser glazing in order to improve the corrosion resistance.By optimizing the laser parameters,a^18μm smooth glazed layer with some vertical cracks was produced on the coating surfaces.The as-sprayed and modified coatings were both exposed to hot corrosion tests at 700 and 1000℃for 4 h in V2O5 molten salt,and the results revealed that the modified one had improved corrosion resistance.After hot corrosion,the glazed layer kept structural integrity,with little evidence of dissolution.However,the vertical cracks in the glazed layer acted as the paths for molten salt penetration,accelerating the corrosion of the non-modified coating.Further optimization of the glazed layer is needed in the future work.
文摘Preconcentration/separation of Co（II）, Fe（III）, Pb（II）, Cr（IIl）, Cu（II） and Cd（II） ions using bis（5-bromo- 2-hydroxy-benzaldehyde）-2-methy1-1,5-pentane diimine （BBHBPDI） on SDS coated alumina has been reported. The influences of the analytical parameters including pH, ligand and SDS amount, type and concentration of eluent and sample volume on metal ions recoveries were investigated. At optimum values of all variables the relative standard deviation are between 2.5-2.7 and preconcentration factor was 375, while recoveries for all understudy metal ions are higher than 95%, determination limits are between 1.5-2.7. The method has been successfully applied to determination of Co（II）, Fe（III）, Pb（II）, Cr（III）, Cu（II） and Cd（II） ions content in some real samples.
