The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstru...The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstructure and interfacial strength of Sn−2Al/W90 interface were investigated.The ultrasound improved the wettability of Sn−2Al filler metal on W90 surface.As the ultrasonic power increased and ultrasonic time increased,the size of Al phase in seam decreased.The maximum value of Sn−2Al/W90 interfacial strength reached 30.1 MPa.Based on the acoustic pressure simulation and bubble dynamics,the intensity of cavitation effect was proportional to ultrasonic power.The generated high temperature and high pressure by cavitation effect reached 83799.6 K and 1.26×10^(14) Pa,respectively.展开更多
Multilayered Pt/Ru modified aluminide coating for thermal barrier coating （TBC） systems has been investi- gated. 2μm Pt＋2 μm Ru＋2 μm Pt was first deposited on nickel-base superalloy DZ125 by electrodeposition, ...Multilayered Pt/Ru modified aluminide coating for thermal barrier coating （TBC） systems has been investi- gated. 2μm Pt＋2 μm Ru＋2 μm Pt was first deposited on nickel-base superalloy DZ125 by electrodeposition, and then the coating was treated by annealing and a conventional pack-cementation aluminizing process. The cyclic oxidation tests were carried out at 1423 K in air. It was found that the thermal cyclic oxidation resistance of Pt/Ru-modified aluminide coating was comparable to that of Pt-modified aluminide coating, which was much better than simply aluminized DZ125. The addition of Ru to Pt-modified aluminide coating increased the resistance to rumpling. The microstructures and phase constitutions of the coating before and after oxidation were investigated.展开更多
Al2O3p/Al composite coatings were prepared on the surface of AZ31 magnesium alloy by plasma spraying technology with mixed powders of Al and Al2O3. An orthogonal test containing six factors and five levels was carried...Al2O3p/Al composite coatings were prepared on the surface of AZ31 magnesium alloy by plasma spraying technology with mixed powders of Al and Al2O3. An orthogonal test containing six factors and five levels was carried out to acquire the optimum technical parameters. Mierostruetures and properties of the composite coatings were studied. The results show that the coatings consist of Al2O3 particulates distributed uniformly and Al matrix, and the interface between the particulate and matrix is continuous, compact and clean. With increasing the mass fraction of Al2O3 in the mixed powders, the volume fraction of Al2O3 in the coatings iacreases. The Al2O3p/Al composite coating with 14% Al2O3 volume fraction has more compact microstrueture and more satisfactory properties.展开更多
To prolong the service lifetime of hot-section components used in marine environment at elevated tem-peratures,it is crucial to explore and develop high-temperature corrosion-resistant coatings.High-velocity oxygen fu...To prolong the service lifetime of hot-section components used in marine environment at elevated tem-peratures,it is crucial to explore and develop high-temperature corrosion-resistant coatings.High-velocity oxygen fuel(HVOF)sprayed NiCoCrAlY,Pt-modified NiCoCrAlY and pre-oxidized Pt-modified NiCoCrAlY coatings were prepared and investigated.This study is concerned with the performance of three coat-ings in a simulated marine environment based on the phase composition of corrosion products and mi-crostructure evolution of coating samples combined with first-principles density functional theory.The results show that the NiCoCrAlY coating was subject to accelerated corrosion and extensive aluminum depletion,leading to premature coating failure.The high-temperature corrosion resistance of Pt-modified NiCoCrAlY coating was found to be better than that of NiCoCrAlY coating.In contrast,the pre-oxidized Pt-modified NiCoCrAlY coating offered long-lasting protection and exhibited the best corrosion resistance,which is attributed to the positive synergistic effect between Pt modification and pre-oxidation.展开更多
Laser specific energy significantly impacts the quality of composite coatings.Ti−Al/WC coatings were prepared on the TC21 alloy through laser cladding with specific energy ranging from 66.7 to 133.3 J/mm^(2).The resul...Laser specific energy significantly impacts the quality of composite coatings.Ti−Al/WC coatings were prepared on the TC21 alloy through laser cladding with specific energy ranging from 66.7 to 133.3 J/mm^(2).The results indicate that the composite coatings primarily comprised Ti_(2)AlC,α_(2)-Ti_(3)Al,γ-TiAl,TiC,and W phases.A gradual increase in the relative intensity of the diffraction peaks of Ti_(2)AlC,α_(2)-Ti_(3)Al,and TiC appeared with the increase of specific energy.When the specific energy was 116.7 J/mm^(2),the Ti−Al/WC coated alloy achieved a maximum micro-hardness of HV0.2766.3,which represented an increase of 1.96 times compared with TC21 alloy,and the minimum wear rate decreased dramatically.Much improvement in tribological properties was attained through the fine-grained strengthening of the(α_(2)+γ)matrix and the dispersion strengthening of self-lubricating Ti_(2)AlC and intertwining TiC.This study provides valuable insights for the development of high-performance Ti−Al composite coatings.展开更多
ZnO thin films co-doped with A1 and Sb with different concentrations and a fixed molar ratio of AlCl3 to SbCl3 at 1：2, are prepared by a sol-gel spin-coating method on glass annealed at 550 ℃ for 2 h in air. The x-r...ZnO thin films co-doped with A1 and Sb with different concentrations and a fixed molar ratio of AlCl3 to SbCl3 at 1：2, are prepared by a sol-gel spin-coating method on glass annealed at 550 ℃ for 2 h in air. The x-ray diffraction results confirm that the ZnO thin films co-doped with Al distortion, and the biaxial stresses are 1.03× 10^8. 3.26× 10^8 and Sb are of wurtzite hexagonal ZnO with a very small 5.23 × 10^8, and 6.97× 10^8 Pa, corresponding to those of the ZnO thin films co-doped with Al and Sb in concentrations of 1.5, 3.0, 4.5, 6.0 at% respectively. The optical properties reveal that the ZnO thin films co-doped with Al and Sb have obviously enhanced transmittance in the visible region. The electrical properties show that ZnO thin film co-doped with Al and Sb in a concentration of 1.5 at% has a lowest resistivity of 2.5 Ω·cm.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52105330,52175307)the Natural Science Foundation of Shandong Province,China(No.ZR2023JQ021)。
文摘The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstructure and interfacial strength of Sn−2Al/W90 interface were investigated.The ultrasound improved the wettability of Sn−2Al filler metal on W90 surface.As the ultrasonic power increased and ultrasonic time increased,the size of Al phase in seam decreased.The maximum value of Sn−2Al/W90 interfacial strength reached 30.1 MPa.Based on the acoustic pressure simulation and bubble dynamics,the intensity of cavitation effect was proportional to ultrasonic power.The generated high temperature and high pressure by cavitation effect reached 83799.6 K and 1.26×10^(14) Pa,respectively.
基金sponsored by the Program for New Century Excellent Talents in University (NCET)the National Natural Science Foundation of China (NSFC,Nos.50731001 and 50971013)the National Institute for Materials Science (NIMS) internship program
文摘Multilayered Pt/Ru modified aluminide coating for thermal barrier coating （TBC） systems has been investi- gated. 2μm Pt＋2 μm Ru＋2 μm Pt was first deposited on nickel-base superalloy DZ125 by electrodeposition, and then the coating was treated by annealing and a conventional pack-cementation aluminizing process. The cyclic oxidation tests were carried out at 1423 K in air. It was found that the thermal cyclic oxidation resistance of Pt/Ru-modified aluminide coating was comparable to that of Pt-modified aluminide coating, which was much better than simply aluminized DZ125. The addition of Ru to Pt-modified aluminide coating increased the resistance to rumpling. The microstructures and phase constitutions of the coating before and after oxidation were investigated.
基金This research was supported by Jilin Province Science Foundation （No. 20090552）.
文摘Al2O3p/Al composite coatings were prepared on the surface of AZ31 magnesium alloy by plasma spraying technology with mixed powders of Al and Al2O3. An orthogonal test containing six factors and five levels was carried out to acquire the optimum technical parameters. Mierostruetures and properties of the composite coatings were studied. The results show that the coatings consist of Al2O3 particulates distributed uniformly and Al matrix, and the interface between the particulate and matrix is continuous, compact and clean. With increasing the mass fraction of Al2O3 in the mixed powders, the volume fraction of Al2O3 in the coatings iacreases. The Al2O3p/Al composite coating with 14% Al2O3 volume fraction has more compact microstrueture and more satisfactory properties.
基金supported by the National Science and Technology Major Project(No.J2019-IV-0006-0074)the Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2021-2-2)+2 种基金the National Natural Science Foundation of China(No.52301116)support by the Joint Funds of the National Natural Science Foundation of China(“Ye Qisun”Science Funds,No.U2241251)the Innovation Engineering Project(No.211-XXXX-N106-01).
文摘To prolong the service lifetime of hot-section components used in marine environment at elevated tem-peratures,it is crucial to explore and develop high-temperature corrosion-resistant coatings.High-velocity oxygen fuel(HVOF)sprayed NiCoCrAlY,Pt-modified NiCoCrAlY and pre-oxidized Pt-modified NiCoCrAlY coatings were prepared and investigated.This study is concerned with the performance of three coat-ings in a simulated marine environment based on the phase composition of corrosion products and mi-crostructure evolution of coating samples combined with first-principles density functional theory.The results show that the NiCoCrAlY coating was subject to accelerated corrosion and extensive aluminum depletion,leading to premature coating failure.The high-temperature corrosion resistance of Pt-modified NiCoCrAlY coating was found to be better than that of NiCoCrAlY coating.In contrast,the pre-oxidized Pt-modified NiCoCrAlY coating offered long-lasting protection and exhibited the best corrosion resistance,which is attributed to the positive synergistic effect between Pt modification and pre-oxidation.
基金supported by the Guangxi Science and Technology Program,China(Nos.Guike AD23026170,Guike AD23026116)the Guangxi Key Laboratory of Manufacturing System and Advanced Manufacturing Technology,China(No.22-35-4-S019)+3 种基金the Research Basic Ability Enhancement Program for Young and Middle-aged Teachers of Guangxi,China(No.2023KY0202)China Postdoctoral Science Foundation(No.2024M753642)the Guilin Science and Technology Development Program(Project),China(No.20220124-10)the Innovation Project of GUET Graduate Education,China(No.2024YCXS008).
文摘Laser specific energy significantly impacts the quality of composite coatings.Ti−Al/WC coatings were prepared on the TC21 alloy through laser cladding with specific energy ranging from 66.7 to 133.3 J/mm^(2).The results indicate that the composite coatings primarily comprised Ti_(2)AlC,α_(2)-Ti_(3)Al,γ-TiAl,TiC,and W phases.A gradual increase in the relative intensity of the diffraction peaks of Ti_(2)AlC,α_(2)-Ti_(3)Al,and TiC appeared with the increase of specific energy.When the specific energy was 116.7 J/mm^(2),the Ti−Al/WC coated alloy achieved a maximum micro-hardness of HV0.2766.3,which represented an increase of 1.96 times compared with TC21 alloy,and the minimum wear rate decreased dramatically.Much improvement in tribological properties was attained through the fine-grained strengthening of the(α_(2)+γ)matrix and the dispersion strengthening of self-lubricating Ti_(2)AlC and intertwining TiC.This study provides valuable insights for the development of high-performance Ti−Al composite coatings.
基金Project supported by the Innovation Foundation of Beijing University of Aeronautics and Astronautics for PhD Graduates, China (Grant No. 292122)the Equipment Research Foundation of China (Grant No. 373974)
文摘ZnO thin films co-doped with A1 and Sb with different concentrations and a fixed molar ratio of AlCl3 to SbCl3 at 1：2, are prepared by a sol-gel spin-coating method on glass annealed at 550 ℃ for 2 h in air. The x-ray diffraction results confirm that the ZnO thin films co-doped with Al distortion, and the biaxial stresses are 1.03× 10^8. 3.26× 10^8 and Sb are of wurtzite hexagonal ZnO with a very small 5.23 × 10^8, and 6.97× 10^8 Pa, corresponding to those of the ZnO thin films co-doped with Al and Sb in concentrations of 1.5, 3.0, 4.5, 6.0 at% respectively. The optical properties reveal that the ZnO thin films co-doped with Al and Sb have obviously enhanced transmittance in the visible region. The electrical properties show that ZnO thin film co-doped with Al and Sb in a concentration of 1.5 at% has a lowest resistivity of 2.5 Ω·cm.
