The double-layer NiCr-Cr_(3)C_(2)/Ni-Zn-Al_(2)O_(3) coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates.The intermediate layers Ni-Zn-Al_(2)O_(3) were fabricated by usin...The double-layer NiCr-Cr_(3)C_(2)/Ni-Zn-Al_(2)O_(3) coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates.The intermediate layers Ni-Zn-Al_(2)O_(3) were fabricated by using low-pressure cold spray (LPCS) method to improve the salt fog corrosion resistance properties of the supersonic plasma spray (SPS) NiCr-Cr_(3)C_(2) coatings.The friction and wear performance for the double-layer and single-layer NiCr-Cr_(3)C_(2) coatings were carried out by line-contact reciprocating sliding,respectively.Combined with the coating surface analysis techniques,the effect of the salt fog corrosion on the tribological properties of the double-layer coatings was studied.The results showed that the double-layer coatings exhibited better wear resistance than that of the single-layer coatings,due to the better corrosion resistance of the intermediate layer;the wear mass losses of the double-layer coatings was reduced by 70%than that of the single layer coatings and the wear mechanism of coatings after salt fog corrosion conditions is mainly corrosion wear.展开更多
The objective of the present work was to determine the influence of the neutral salt spray corrosion on the wear resistance of HVOF sprayed NiCr-Cr_3C_2 coating with intermediate layer. Ni-Zn-Al_2O_3 coatings as inter...The objective of the present work was to determine the influence of the neutral salt spray corrosion on the wear resistance of HVOF sprayed NiCr-Cr_3C_2 coating with intermediate layer. Ni-Zn-Al_2O_3 coatings as interlayers were prepared by low pressure cold spray(LPCS) between NiCr-Cr_3C_2 cermet coatings to form a sandwich structure to enhance the corrosion resistance properties. The tribological properties were examined using the UMT-3 fricition and wear tester by line-contact reciprocating sliding under dry and salt spray one week corrosion. The morphology, element distribution, and phase compositions of the coating and worn sufaces were analyzed by using scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction respectively. The corrosion behavior of the coating was studied by the open-circuit potential, the electrochemical impedance spectroscopy, potentiodynamic polarization, and salt spray corrosion methods. It is found that the sandwich structured coating has better corrosion resistance than the single layer coating. The results show that under dry wear conditions, the wear mechanism is abrasive and adhesive wear, whereas under salt spray corrosion conditions it becomes corrosion wear. The friction coefficient of the sandwich structured coating after salt spray corrosion is slightly lower than the dry friction coefficient, but the weight of the wear loss is lower than that under dry condition.展开更多
In this article,the absence of self-replenishing of cold spray is studied by examining the thick coating deposited around the pre-drilled microsize hole.Thick copper coating was deposited around the microsize holes(ab...In this article,the absence of self-replenishing of cold spray is studied by examining the thick coating deposited around the pre-drilled microsize hole.Thick copper coating was deposited around the microsize holes(about 200 and 500μm) using cold spraying methods on copper substrate,the cross-section of cavity around the hole were observed with SEM to investigate the characteristics of cavity.Computational methods were also used to investigate the original formation reason of the cavity.The results indicate:the original formation reason of cavity is that particles are too closed when impact onto the substrate.The repellant force between the particles perpendicular to the impaction direction will lead to porosity if the particles are too close.Much lower flatten ratio occurred for succeeding particle if the particles are too close at the same point because the momentum energy convert to the former particle's deformation.A high probability of above two phenomenon resulting from high powder feeding rate will form the original cavity.In relative wider cavity,coating can be deposited in the bottom,while in the relative narrow cavity,coating can not be deposited.The thickness of the coating in the cavity is much thinner than coating around the cavity.The cavity grow larger and larger on pre-drilled holes just as the regime effect of cold spray of fixed location deposition.展开更多
基金Fundamental Research Funds for Central Universities Project (No. 1CX05021A)Shandong Provincial Key R&D Plan Project (No. 2GHY15108)Shandong Postdoctoral Innovation Project and Qingdao Postdoctoral Applied Research Project。
文摘The double-layer NiCr-Cr_(3)C_(2)/Ni-Zn-Al_(2)O_(3) coatings with sufficient corrosion and wear resistance were prepared on low carbon steel substrates.The intermediate layers Ni-Zn-Al_(2)O_(3) were fabricated by using low-pressure cold spray (LPCS) method to improve the salt fog corrosion resistance properties of the supersonic plasma spray (SPS) NiCr-Cr_(3)C_(2) coatings.The friction and wear performance for the double-layer and single-layer NiCr-Cr_(3)C_(2) coatings were carried out by line-contact reciprocating sliding,respectively.Combined with the coating surface analysis techniques,the effect of the salt fog corrosion on the tribological properties of the double-layer coatings was studied.The results showed that the double-layer coatings exhibited better wear resistance than that of the single-layer coatings,due to the better corrosion resistance of the intermediate layer;the wear mass losses of the double-layer coatings was reduced by 70%than that of the single layer coatings and the wear mechanism of coatings after salt fog corrosion conditions is mainly corrosion wear.
基金Funded by the High-Tech Research and Development Program of China(No.2012AA09A203)the Fundmental Research Funds for the Central Universities(No.15CX06061A)the Postgraduate Innovation Project of China University of Petroleum(East China)(No.YCXJ2016059)
文摘The objective of the present work was to determine the influence of the neutral salt spray corrosion on the wear resistance of HVOF sprayed NiCr-Cr_3C_2 coating with intermediate layer. Ni-Zn-Al_2O_3 coatings as interlayers were prepared by low pressure cold spray(LPCS) between NiCr-Cr_3C_2 cermet coatings to form a sandwich structure to enhance the corrosion resistance properties. The tribological properties were examined using the UMT-3 fricition and wear tester by line-contact reciprocating sliding under dry and salt spray one week corrosion. The morphology, element distribution, and phase compositions of the coating and worn sufaces were analyzed by using scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction respectively. The corrosion behavior of the coating was studied by the open-circuit potential, the electrochemical impedance spectroscopy, potentiodynamic polarization, and salt spray corrosion methods. It is found that the sandwich structured coating has better corrosion resistance than the single layer coating. The results show that under dry wear conditions, the wear mechanism is abrasive and adhesive wear, whereas under salt spray corrosion conditions it becomes corrosion wear. The friction coefficient of the sandwich structured coating after salt spray corrosion is slightly lower than the dry friction coefficient, but the weight of the wear loss is lower than that under dry condition.
基金Science and Technology Foundation of State Key Laboratory for Marine Corrosion and Protection(9140C2505030805)
文摘In this article,the absence of self-replenishing of cold spray is studied by examining the thick coating deposited around the pre-drilled microsize hole.Thick copper coating was deposited around the microsize holes(about 200 and 500μm) using cold spraying methods on copper substrate,the cross-section of cavity around the hole were observed with SEM to investigate the characteristics of cavity.Computational methods were also used to investigate the original formation reason of the cavity.The results indicate:the original formation reason of cavity is that particles are too closed when impact onto the substrate.The repellant force between the particles perpendicular to the impaction direction will lead to porosity if the particles are too close.Much lower flatten ratio occurred for succeeding particle if the particles are too close at the same point because the momentum energy convert to the former particle's deformation.A high probability of above two phenomenon resulting from high powder feeding rate will form the original cavity.In relative wider cavity,coating can be deposited in the bottom,while in the relative narrow cavity,coating can not be deposited.The thickness of the coating in the cavity is much thinner than coating around the cavity.The cavity grow larger and larger on pre-drilled holes just as the regime effect of cold spray of fixed location deposition.
