Ni-P-SiC_(P) coatings were deposited on 42CrMo steel by electroless plating.The surface morphologies and phase structures of the Ni-P-SiC_(P) coatings processed under different SiC_(P) concentrations at different heat...Ni-P-SiC_(P) coatings were deposited on 42CrMo steel by electroless plating.The surface morphologies and phase structures of the Ni-P-SiC_(P) coatings processed under different SiC_(P) concentrations at different heat treatment temperatures were analyzed.The microhardness,corrosion resistance,and wear resistance of the Ni-P-SiC_(P) coatings were studied.Results show that Ni-P-SiC_(P) coatings exhibit cauliflower-like morphology.Increasing the SiC_(P) concentration can reduce the size of cellular structure.The microhardness and corrosion resistance are initially increased and then decreased with the increase in SiC_(P) concentration.The maximum microhardness and corrosion potential are 7379 MPa and−0.363 V,respectively,when the SiC_(P) concentration is 5 g/L.The Ni-P-SiC_(P) coatings exhibit an amorphous structure,and the width of the diffuse diffraction peak becomes narrower with the increase in SiC_(P) concentration.It is suggested that SiC_(P) inhibits the deposition of P and promotes the microcrystalline transformation.After heat treatment at 350℃,the Ni-P-SiC_(P) coatings are crystallized,resulting in the precipitation of Ni3P phase.Heat treatment at 400℃ for 1 h maximizes the structure.The synergistic effect of the Ni3P precipitate phase and SiC_(P) dispersion phase promotes the densification of the cellular structure,leading to the optimal microhardness(13828 MPa),optimal corrosion resistance(−0.277 V),and excellent wear resistance.The wear mechanism is dominated by micro-cutting abrasive wear with slight adhesive and oxidative wear.展开更多
Ni-P-nano Al2O3 composite coatings were deposited by electroless plating,and their microstructures were observed by SEM（scanning electron microscope）.The microhardness and the wear resistance of the Ni-P-nano Al2O3 ...Ni-P-nano Al2O3 composite coatings were deposited by electroless plating,and their microstructures were observed by SEM（scanning electron microscope）.The microhardness and the wear resistance of the Ni-P-nano Al2O3 composite coatings were measured using microhardness tester and block-on-ring tribometer,respectively,and the comparison with those of Ni-P coatings or Ni-P-micro Al2O3 coating was given.The influences of aging temperature on their hardness and wear resistance were analyzed.The results showed that the nano Al2O3 particles were distributed uniformly in the Ni-P-Al2O3 coatings.Among three kinds of Ni-P based coatings,the hardness and wear resistance of Ni-P-nano Al2O3 coatings were largest,and the maximum values could be obtained at 400 ℃.This indicated that the precipitation of nano Al2O3 particles would improve the hardness and wear resistance of the Ni-P coatings.展开更多
Magnesium(Mg)and its alloys have received much attention in a lot of areas due to their special chemical and physical properties.Nevertheless,high corrosion rates are a limiting factor.The plasma electrolytic oxidatio...Magnesium(Mg)and its alloys have received much attention in a lot of areas due to their special chemical and physical properties.Nevertheless,high corrosion rates are a limiting factor.The plasma electrolytic oxidation(PEO)technique is a simple approach to place an oxide film on the surface of light metals like Mg alloys.This method has been considered for controlling the rate of corrosion and improving some other properties.On the other hand,PEO coatings cannot make enough protection of Magnesium alloys for a long time due to porosity and fine cracks.Therefore,PEO-based composite coatings are used to make adequate corrosion protection on the Mg alloys surface.The popularity of these coatings is due to their good corrosion resistance,simplicity,high coating capability,and cost-effectiveness in complex segments.Formation of an organic layer on the surface of PEO coating is one of the effective methods to close the defects and thus prevent the corrosive species penetration into the substrate.Coating the PEO coating with a polymer layer can be a good solution to control the amount of damage and improve the corrosion and abrasion resistance.In addition,PEO coating can eliminate the problems of insufficient adhesion of polymer coatings and is considered as a suitable base for composite coatings.This review paper presents the corrosion and abrasion behavior of the PEO/Polymer dual coating system on Mg alloys.Given the fundamental role of coatings thickness and morphology in wear and corrosion behavior,these aspects have been highly discussed in this study.展开更多
基金Science Research Project of Handan Bureau of Science and Technology(21422075242)。
文摘Ni-P-SiC_(P) coatings were deposited on 42CrMo steel by electroless plating.The surface morphologies and phase structures of the Ni-P-SiC_(P) coatings processed under different SiC_(P) concentrations at different heat treatment temperatures were analyzed.The microhardness,corrosion resistance,and wear resistance of the Ni-P-SiC_(P) coatings were studied.Results show that Ni-P-SiC_(P) coatings exhibit cauliflower-like morphology.Increasing the SiC_(P) concentration can reduce the size of cellular structure.The microhardness and corrosion resistance are initially increased and then decreased with the increase in SiC_(P) concentration.The maximum microhardness and corrosion potential are 7379 MPa and−0.363 V,respectively,when the SiC_(P) concentration is 5 g/L.The Ni-P-SiC_(P) coatings exhibit an amorphous structure,and the width of the diffuse diffraction peak becomes narrower with the increase in SiC_(P) concentration.It is suggested that SiC_(P) inhibits the deposition of P and promotes the microcrystalline transformation.After heat treatment at 350℃,the Ni-P-SiC_(P) coatings are crystallized,resulting in the precipitation of Ni3P phase.Heat treatment at 400℃ for 1 h maximizes the structure.The synergistic effect of the Ni3P precipitate phase and SiC_(P) dispersion phase promotes the densification of the cellular structure,leading to the optimal microhardness(13828 MPa),optimal corrosion resistance(−0.277 V),and excellent wear resistance.The wear mechanism is dominated by micro-cutting abrasive wear with slight adhesive and oxidative wear.
基金Item Sponsored by Jiangsu Natural Science Foundation of China(04KJB430013)Jiangsu Key Laboratory of Friction Wear Opening Foundation
文摘Ni-P-nano Al2O3 composite coatings were deposited by electroless plating,and their microstructures were observed by SEM（scanning electron microscope）.The microhardness and the wear resistance of the Ni-P-nano Al2O3 composite coatings were measured using microhardness tester and block-on-ring tribometer,respectively,and the comparison with those of Ni-P coatings or Ni-P-micro Al2O3 coating was given.The influences of aging temperature on their hardness and wear resistance were analyzed.The results showed that the nano Al2O3 particles were distributed uniformly in the Ni-P-Al2O3 coatings.Among three kinds of Ni-P based coatings,the hardness and wear resistance of Ni-P-nano Al2O3 coatings were largest,and the maximum values could be obtained at 400 ℃.This indicated that the precipitation of nano Al2O3 particles would improve the hardness and wear resistance of the Ni-P coatings.
文摘Magnesium(Mg)and its alloys have received much attention in a lot of areas due to their special chemical and physical properties.Nevertheless,high corrosion rates are a limiting factor.The plasma electrolytic oxidation(PEO)technique is a simple approach to place an oxide film on the surface of light metals like Mg alloys.This method has been considered for controlling the rate of corrosion and improving some other properties.On the other hand,PEO coatings cannot make enough protection of Magnesium alloys for a long time due to porosity and fine cracks.Therefore,PEO-based composite coatings are used to make adequate corrosion protection on the Mg alloys surface.The popularity of these coatings is due to their good corrosion resistance,simplicity,high coating capability,and cost-effectiveness in complex segments.Formation of an organic layer on the surface of PEO coating is one of the effective methods to close the defects and thus prevent the corrosive species penetration into the substrate.Coating the PEO coating with a polymer layer can be a good solution to control the amount of damage and improve the corrosion and abrasion resistance.In addition,PEO coating can eliminate the problems of insufficient adhesion of polymer coatings and is considered as a suitable base for composite coatings.This review paper presents the corrosion and abrasion behavior of the PEO/Polymer dual coating system on Mg alloys.Given the fundamental role of coatings thickness and morphology in wear and corrosion behavior,these aspects have been highly discussed in this study.
