By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and t...By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and the bonding strength between the coating and the substrate were tested with a HV-1000 microhardness tester and a mechanical universal testing machine. The surface microstructure, cross-section and tensile fracture surface of the coating were observed with a scanning electron microscope(SEM). Correspondingly, the influences of the preheat treatment temperature of the bronze powder and the Al_2O_3 content on the coating performance were investigated. The results indicate that the hardness of bronze powders decreased and the coating deposition rate increased after the preheating treatment of the bronze powder. The Al_2O_3 content in the mixed powders contributed to the deformation of bronze powders during the spraying process. This trend resulted in varied performance of the coating.展开更多
Amorphous alloys without crystalline defects(dislocation,crystal boundary)are ideal hydrophobic coating materials due to their low surface energy.This work used a synergistic method of detonation spraying and surface ...Amorphous alloys without crystalline defects(dislocation,crystal boundary)are ideal hydrophobic coating materials due to their low surface energy.This work used a synergistic method of detonation spraying and surface modification to obtain the superhydrophobic Febased amorphous coatings with high hardness and dense structure on the Q 235 substrate.The results showed that the water contact angles(WCA)of the superhydrophobic coating was 160°±3.6°,and water droplets could bounce off the superhydrophobic coating surface,illustrating the excellent self-cleaning performance of coating.Notably,the corrosion current density(i_(corr))of the superhydrophobic coating further decreased by 2 orders of magnitude down to8.008×10^(-8)A·cm^(-2)compared to the as-deposited coating with 5.473×10^(-6)A·cm^(-2);the corrosion potential(E_(corr))of the superhydrophobic coating shifted by 34 mV to the positive side compared with that of the as-deposited coating(-310 mV).Likewise,the impedance modulus|Z|values of the superhydrophobic coating increased by nearly2 orders of magnitude up to 1×10^(5.6)compared to the asdeposited coating with 1×10^(3.8).Even through lasting immersion in NaCl for 10 days,|Z|values of the superhydrophobic coating were still much higher than those of the as-deposited coating.The superhydrophobic Fe-based amorphous coatings could respond to their applications under extreme conditions due to their excellent hydrophobicity and self-cleaning properties,illustrating their promising future in aerospace,automotive,and machinery industries.展开更多
A nickel alloy matrix high-temperature self-lubricating coating(77.5 wt%(Ni-Cr-Mo-Al)-12.5 wt%Ag-10 wt%BaF2/CaF2)was prepared by plasma spraying technique.Results show that the Vickers microhardness of coating is(2.9&...A nickel alloy matrix high-temperature self-lubricating coating(77.5 wt%(Ni-Cr-Mo-Al)-12.5 wt%Ag-10 wt%BaF2/CaF2)was prepared by plasma spraying technique.Results show that the Vickers microhardness of coating is(2.9±0.5)GPa,and the average bonding strength is about(35.6±0.5)MPa.The coating rubbing against Inconel 718 superalloy pin exhibits superior tribological performance with coefficient of friction(COF)of below 0.25 and wear rate of 8.2×10^(-5)-15.2×10^(-5)mm^(3)·N^(-1)·m^(-1)at a wide temperature range from 25 to 800℃,and the COF and the wear rate are slightly reduced with temperature increasing.The low COF and wear rate were attributed to the synergistic effects of Ag,BaF_(2)/CaF_(2),Ag2MoO_(4)and BaMoO_(4).展开更多
基金financially supported by the National Key Research and Development Program of China(No.2016YFE0111400)the Program on Key Research Project of Gansu Province(No.17YF1WA159)the National High-end Foreign Experts Program of China(No.GTD20156200088)
文摘By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and the bonding strength between the coating and the substrate were tested with a HV-1000 microhardness tester and a mechanical universal testing machine. The surface microstructure, cross-section and tensile fracture surface of the coating were observed with a scanning electron microscope(SEM). Correspondingly, the influences of the preheat treatment temperature of the bronze powder and the Al_2O_3 content on the coating performance were investigated. The results indicate that the hardness of bronze powders decreased and the coating deposition rate increased after the preheating treatment of the bronze powder. The Al_2O_3 content in the mixed powders contributed to the deformation of bronze powders during the spraying process. This trend resulted in varied performance of the coating.
基金financially supported by the National Natural Science Foundation of China(Nos.51901092,52075234)the Program of"Science and Technology International Cooperation Demonstrative Base of Metal Surface Engineering along the Silk Road(No.2017D01003)"+3 种基金the"111"project(No.D21032)the Key Research Program of Education Department of Gansu Province(No.GSSYLXM-03)the Natural Science Foundation of Gansu Province(No.20JR5RA431)Hongliu Distinguished Young Talent Support Program of Lanzhou University of Technology,and the Open Fund Project of Hunan Province Key Laboratory of Electromagnetic Equipment Design and Manufacturing,Hunan Institute of Technology(No.DC202001)。
文摘Amorphous alloys without crystalline defects(dislocation,crystal boundary)are ideal hydrophobic coating materials due to their low surface energy.This work used a synergistic method of detonation spraying and surface modification to obtain the superhydrophobic Febased amorphous coatings with high hardness and dense structure on the Q 235 substrate.The results showed that the water contact angles(WCA)of the superhydrophobic coating was 160°±3.6°,and water droplets could bounce off the superhydrophobic coating surface,illustrating the excellent self-cleaning performance of coating.Notably,the corrosion current density(i_(corr))of the superhydrophobic coating further decreased by 2 orders of magnitude down to8.008×10^(-8)A·cm^(-2)compared to the as-deposited coating with 5.473×10^(-6)A·cm^(-2);the corrosion potential(E_(corr))of the superhydrophobic coating shifted by 34 mV to the positive side compared with that of the as-deposited coating(-310 mV).Likewise,the impedance modulus|Z|values of the superhydrophobic coating increased by nearly2 orders of magnitude up to 1×10^(5.6)compared to the asdeposited coating with 1×10^(3.8).Even through lasting immersion in NaCl for 10 days,|Z|values of the superhydrophobic coating were still much higher than those of the as-deposited coating.The superhydrophobic Fe-based amorphous coatings could respond to their applications under extreme conditions due to their excellent hydrophobicity and self-cleaning properties,illustrating their promising future in aerospace,automotive,and machinery industries.
基金the International Science and Technology Cooperation Program of China(No.2015DFR51090)the National Program on Key Research Project of China(No.2016YFE0111400)。
文摘A nickel alloy matrix high-temperature self-lubricating coating(77.5 wt%(Ni-Cr-Mo-Al)-12.5 wt%Ag-10 wt%BaF2/CaF2)was prepared by plasma spraying technique.Results show that the Vickers microhardness of coating is(2.9±0.5)GPa,and the average bonding strength is about(35.6±0.5)MPa.The coating rubbing against Inconel 718 superalloy pin exhibits superior tribological performance with coefficient of friction(COF)of below 0.25 and wear rate of 8.2×10^(-5)-15.2×10^(-5)mm^(3)·N^(-1)·m^(-1)at a wide temperature range from 25 to 800℃,and the COF and the wear rate are slightly reduced with temperature increasing.The low COF and wear rate were attributed to the synergistic effects of Ag,BaF_(2)/CaF_(2),Ag2MoO_(4)and BaMoO_(4).
