Magnesium aluminate spinel -corundum composite was prepared with waste slide plate and magnesia carbon brick. Microstructure and sintering ability of as-prepared magnesium aluminate spinel -corundum composite were inv...Magnesium aluminate spinel -corundum composite was prepared with waste slide plate and magnesia carbon brick. Microstructure and sintering ability of as-prepared magnesium aluminate spinel -corundum composite were investigated with XRD, SEM, and DSC/TG. With the addition of waste slide plate increasing or synthesis tem- perature rising, the bulk density of the specimen increases and the apparent porosity decreases, but the crystallinity of the specimen decreases and the magnesium alaminate spinel phase increases. The obtained composite contains 72% spinel and 26% corundum. Primary phase and secondary phase are bonded by glass phase. The results show that it is feasible to synthesis magnesium aluminate spinel - corundum material with waste slide plate and magnesia carbon brick.展开更多
The researchers made magnesium aluminum composite panels by asymmetric metal packaging and studied rolling temperature,holding time,and high temperature heat treatment,such as short time and low temperatures over long...The researchers made magnesium aluminum composite panels by asymmetric metal packaging and studied rolling temperature,holding time,and high temperature heat treatment,such as short time and low temperatures over long periods of time parameters under the new preparation method.We tested the new magnesium aluminum composite panels’tensing properties and bending performance by using scanning electric mirror and EDS.It is concluded that the new magnesium aluminum composite panels’elongation is 24%under the tensile strength of 260 MPa.Regarding performance when compared with other methods,traditional magnesium aluminum composite panels’elongation is 10%,which shows its advanced nature.At the same time,bending performance test showed that the combination of the composite board has higher performance,offering the reference value for the preparation of magnesium–aluminum composite plate.展开更多
The physical characteristics and microstructure of the fluoride film formed during activation were investigated using SEM,XPS and SAM,and its stability in electroless nickel(EN) bath was analyzed.The effects of the fl...The physical characteristics and microstructure of the fluoride film formed during activation were investigated using SEM,XPS and SAM,and its stability in electroless nickel(EN) bath was analyzed.The effects of the fluoride film on EN deposition were studied additionally.The results show that the fluoride film on magnesium alloys is a kind of porous film composed of MgF2 with thickness of 1.6-3.2 μm.The composition of the activation bath and pretreatment of EN processing have influence on the composition of the fluoride film.The fluoride is stable and dissolves little in EN bath;as a result,the fluoride film can protect magnesium substrate from the corrosion of EN bath.The composition of fluoride determines the initial deposition of EN and part of the fluoride film finally exists as inclusion in EN coating.展开更多
In recent years,magnesium(Mg)has evolved as a salient material,in affiliation with electroless nickel(Ni)coating,which have found applications in automobiles,aerospace and confederate fields attributing to its excelle...In recent years,magnesium(Mg)has evolved as a salient material,in affiliation with electroless nickel(Ni)coating,which have found applications in automobiles,aerospace and confederate fields attributing to its excellent inherent weight sensitive properties.However,being acknowledged for its remarkable auxiliary properties like flexible machining,appreciable weight sensitivity and ability to be patently diecast into mesh constructs,magnesium is prejudiced by aeronautical standards predominantly for its inferior corrosion resistance properties.In this sense,electroless nickel plating on magnesium and its alloys has been suggested to extricate it from corrosion problem and make it more competitive in industrial and defence applications.Autocatalytic fixation of metal ions onto respective substrates accrues and alters their mechanical,electrochemical and tribological properties,destitute of any electric current aid.This proficiently identified technique is prosecuted with the assistance of a series of sequenced operations involving a prior pretreatment,which corresponds to the chemical cleaning of the substrate surface;electroless coating;and a later activation process which is a mild etching of the electroless coated surface.The susceptibility of magnesium to this methodology has advanced and propagated its exercise and applicability in aircraft,satellites and allied aeronautical fields.Contemporarily,researchers have proposed various eco-friendly and modified duplex and composite coatings which have transmuted properties of these appendages by tailoring alloy compositions and reagents employed.This review article systematically colligates various considerations and evaluations on electroless nickel applications of magnesium and its alloys and explicates how it anchors its practice in the respective domains.Furthermore,a comprehensive analysis is devised based on the pre-existing treatment methods for accomplishing the same.展开更多
A direct electroless Ni-P plating treatment was applied to AZ91D magnesium alloy for improving its corrosion resistance and wear resistance. Corrosion resistance of the Ni-P coatings was evaluated by potentiodynamic p...A direct electroless Ni-P plating treatment was applied to AZ91D magnesium alloy for improving its corrosion resistance and wear resistance. Corrosion resistance of the Ni-P coatings was evaluated by potentiodynamic polarization and immersing experiments in 3.5% NaCl solution. The wear resistance of the coatings was investigated by the wear track and the mass change after ball-on-disk experiment. The results show that corrosion resistance and wear resistance of the AZ91D alloy are greatly improved after direct electroless Ni-P plating. No discoloration is noticed until 4 d of immersion in 3.5% NaCl solution. Potentiodynamic polarization experiments show that the free corrosion potential of magnesium alloy is shifted from -1 500 mV to -250 mV and passivation occurs at 1 350 mV after direct electroless plating. The friction coefficients and wear rates of Ni-P coating and Ni-P coating after tempering are 0.10-0.351, 9.038×10-3 mm3/m and 0.13-0.177, 3.056×10-4 mm3/m, respectively, at a load of 1.5 N with dry sliding. Although minor hurt on corrosion resistance was caused, significant improvement of wear resistance was obtained after tempering treatment of the coating.展开更多
A novel Ni-P-SiC composite coating was prepared by electroless plating in order to improve the corrosion capacity and wear resistance of AZ91D magnesium alloy.The influence of pH values on deposition rates and propert...A novel Ni-P-SiC composite coating was prepared by electroless plating in order to improve the corrosion capacity and wear resistance of AZ91D magnesium alloy.The influence of pH values on deposition rates and properties of the coatings was studied.The microstructure and phase structure of the Ni-P-SiC coatings were analyzed by scanning electron microscopy(SEM)and X-ray diffractometry(XRD).The corrosion and wear resistance performances of the coatings were also investigated through electrochemical technique and pin-on-disk tribometer,respectively.The results indicate that the composite coating is composed of Ni, P and SiC.It exhibits an amorphous structure and good adhesion to the substrate.The coatings have higher open circuit potential than that of the substrate.The composite coating obtained at pH value of 5.2 possesses optimal integrated properties,which shows similar corrosion resistance and ascendant wear resistance properties to the substrate.展开更多
Polymeric nano-film on the surface of Mg-Mn-Ce magnesium alloy was fabricated by polymer plating of 6-dihexylamino-1,3,5-triazine-2,4-dithiol monosodium(DHN) to improve its corrosion resistance.The electrochemical rea...Polymeric nano-film on the surface of Mg-Mn-Ce magnesium alloy was fabricated by polymer plating of 6-dihexylamino-1,3,5-triazine-2,4-dithiol monosodium(DHN) to improve its corrosion resistance.The electrochemical reaction process was analyzed by cyclic voltammetry and two obvious peaks of oxidation reaction were observed.The static contact angle of distilled water on polymer-plated surface can be up to 106.3°while on the blank surface it is 45.8°.Potentiodynamic polarization results show that the polymeric film can increase the corrosion potential from -1.594 V vs SCE for blank to -0.382 V vs SCE.The results of electrochemical impedance spectroscopy indicate that the charge transfer resistances of blank and polymer-plated Mg-Mn-Ce alloy are 485Ω·cm^2 and 2 717Ω·cm^2,respectively.The method of polymer plating can provide a novel approach for fabricating hydrophobic film on Mg-Mn-Ce alloy surface and improving its anti-corrosion property.展开更多
Electroless nickel-plating on die cast magnesium alloy AZ91D was investigated. Growth of the electroless nickel-plating coating was characterized using scanning electron microscopy. Corrosion resistance of the coating...Electroless nickel-plating on die cast magnesium alloy AZ91D was investigated. Growth of the electroless nickel-plating coating was characterized using scanning electron microscopy. Corrosion resistance of the coating was evaluated by open circuit potential and potentiodynamic polarization curves in 3.5%(mass fraction) NaCl solution. The results show that plating deposition is initiated on the crevices and then spread onto primary α phase. The corrosion potentials for die cast magnesium alloy AZ91D and nickel-plating coating are about -1.45 V and -0.36 V(vs. SCE),respectively. No discoloration,cracks,blisters,or peeling appear by heat-quench test. The results show that the corrosion potential of Ni-P coating is increased by 1 000 mV and corrosion resistance for die cast magnesium alloy AZ91D is improved. The adhesion between the coating and the substrate is excellent. Electroless nickel plating is a promising method to enhance magnesium alloys resistance for attacking.展开更多
An electroless Ni-P plating treatment was applied on AZ91D magnesium alloy to improve its corrosion resistance. Optimum pretreatment conditions and optimum bath of electroless nickel plating for magnesium alloy were f...An electroless Ni-P plating treatment was applied on AZ91D magnesium alloy to improve its corrosion resistance. Optimum pretreatment conditions and optimum bath of electroless nickel plating for magnesium alloy were found through many experiments. In order to avoid bother of pre-plating medium layer, a set of procedure of direct electroless Ni-P under the acid condition was investigated. The properties of the coating with 10% phosphorus were investigated. The results show that a coating with high hardness, low porosity and good adhesive strength is obtained. X-ray diffraction patterns show that the structure of the coating is an amorphous phase. After annealing at 400℃, the amorphous phase of Ni-P is transformed to crystalline phases, and some intermetallics as Ni3P and Ni5P2 are deposited from Ni-P solid solution along with an enhancing hardness from Hv 450 to Hv 910.展开更多
Electroplating zinc coating as transition layer of electroless nickel plating on AM60 magnesium alloys was investigated. The zinc film can be deposited in a pyrophosphate bath at 50-60℃under current density of 0.5-1....Electroplating zinc coating as transition layer of electroless nickel plating on AM60 magnesium alloys was investigated. The zinc film can be deposited in a pyrophosphate bath at 50-60℃under current density of 0.5-1.5 A/dm2. A new fore treatment technology was applied by acid cleaning with a solution containing molybdate and phosphorous acid, by alkaline cleaning in a bath containing molybdate and sodium hydroxide. The subsequent electroless plating was carried out in nickel sulfate bath. The SEM observation shows that the deposition is uniform and compact. The polarization curve measurements show that the corrosion potential of the zinc plating in 3.5% NaCl is about -1.3 V(vs SCE) which is noble than that of magnesium substrate. The zinc electroplating can be applied as the pretreatment process for electroless nickel plating on magnesium alloys.展开更多
Magnesium alloys covered with metal coating display excellent corrosion resistance,wear resistance,conductivity and electromagnetic shielding properties.The electroless plating Ni-P as bottom layer following the elect...Magnesium alloys covered with metal coating display excellent corrosion resistance,wear resistance,conductivity and electromagnetic shielding properties.The electroless plating Ni-P as bottom layer following the electroplating nickel as surface layer on AZ91D magnesium alloy was investigated.The coating surface morphology was observed with SEM and the structure was analyzed with XRD.Electrochemical tests and salt spray tests were carried out to study the corrosion resistance.The experimental results indicate that the dual coating is uniform,compact and pore-free.The adhesion strength between magnesium alloy substrate and electroless plating Ni-P bottom layer and electroplating nickel surface layer is perfect.The corrosion resistance of AZ91D magnesium alloy is greatly improved after being protected with the dual coating.展开更多
文摘Magnesium aluminate spinel -corundum composite was prepared with waste slide plate and magnesia carbon brick. Microstructure and sintering ability of as-prepared magnesium aluminate spinel -corundum composite were investigated with XRD, SEM, and DSC/TG. With the addition of waste slide plate increasing or synthesis tem- perature rising, the bulk density of the specimen increases and the apparent porosity decreases, but the crystallinity of the specimen decreases and the magnesium alaminate spinel phase increases. The obtained composite contains 72% spinel and 26% corundum. Primary phase and secondary phase are bonded by glass phase. The results show that it is feasible to synthesis magnesium aluminate spinel - corundum material with waste slide plate and magnesia carbon brick.
基金the Shanxi Province University Science and Technology innovation project(2014108).
文摘The researchers made magnesium aluminum composite panels by asymmetric metal packaging and studied rolling temperature,holding time,and high temperature heat treatment,such as short time and low temperatures over long periods of time parameters under the new preparation method.We tested the new magnesium aluminum composite panels’tensing properties and bending performance by using scanning electric mirror and EDS.It is concluded that the new magnesium aluminum composite panels’elongation is 24%under the tensile strength of 260 MPa.Regarding performance when compared with other methods,traditional magnesium aluminum composite panels’elongation is 10%,which shows its advanced nature.At the same time,bending performance test showed that the combination of the composite board has higher performance,offering the reference value for the preparation of magnesium–aluminum composite plate.
基金Project(50101007) supported by the National Science Natural Foundation of China
文摘The physical characteristics and microstructure of the fluoride film formed during activation were investigated using SEM,XPS and SAM,and its stability in electroless nickel(EN) bath was analyzed.The effects of the fluoride film on EN deposition were studied additionally.The results show that the fluoride film on magnesium alloys is a kind of porous film composed of MgF2 with thickness of 1.6-3.2 μm.The composition of the activation bath and pretreatment of EN processing have influence on the composition of the fluoride film.The fluoride is stable and dissolves little in EN bath;as a result,the fluoride film can protect magnesium substrate from the corrosion of EN bath.The composition of fluoride determines the initial deposition of EN and part of the fluoride film finally exists as inclusion in EN coating.
文摘In recent years,magnesium(Mg)has evolved as a salient material,in affiliation with electroless nickel(Ni)coating,which have found applications in automobiles,aerospace and confederate fields attributing to its excellent inherent weight sensitive properties.However,being acknowledged for its remarkable auxiliary properties like flexible machining,appreciable weight sensitivity and ability to be patently diecast into mesh constructs,magnesium is prejudiced by aeronautical standards predominantly for its inferior corrosion resistance properties.In this sense,electroless nickel plating on magnesium and its alloys has been suggested to extricate it from corrosion problem and make it more competitive in industrial and defence applications.Autocatalytic fixation of metal ions onto respective substrates accrues and alters their mechanical,electrochemical and tribological properties,destitute of any electric current aid.This proficiently identified technique is prosecuted with the assistance of a series of sequenced operations involving a prior pretreatment,which corresponds to the chemical cleaning of the substrate surface;electroless coating;and a later activation process which is a mild etching of the electroless coated surface.The susceptibility of magnesium to this methodology has advanced and propagated its exercise and applicability in aircraft,satellites and allied aeronautical fields.Contemporarily,researchers have proposed various eco-friendly and modified duplex and composite coatings which have transmuted properties of these appendages by tailoring alloy compositions and reagents employed.This review article systematically colligates various considerations and evaluations on electroless nickel applications of magnesium and its alloys and explicates how it anchors its practice in the respective domains.Furthermore,a comprehensive analysis is devised based on the pre-existing treatment methods for accomplishing the same.
基金Project(2006031117-04) supported by Tackling Key Science and Technology of Shanxi Province, ChinaProject(07010763) supported by Academic Innovation of Taiyuan City, China
文摘A direct electroless Ni-P plating treatment was applied to AZ91D magnesium alloy for improving its corrosion resistance and wear resistance. Corrosion resistance of the Ni-P coatings was evaluated by potentiodynamic polarization and immersing experiments in 3.5% NaCl solution. The wear resistance of the coatings was investigated by the wear track and the mass change after ball-on-disk experiment. The results show that corrosion resistance and wear resistance of the AZ91D alloy are greatly improved after direct electroless Ni-P plating. No discoloration is noticed until 4 d of immersion in 3.5% NaCl solution. Potentiodynamic polarization experiments show that the free corrosion potential of magnesium alloy is shifted from -1 500 mV to -250 mV and passivation occurs at 1 350 mV after direct electroless plating. The friction coefficients and wear rates of Ni-P coating and Ni-P coating after tempering are 0.10-0.351, 9.038×10-3 mm3/m and 0.13-0.177, 3.056×10-4 mm3/m, respectively, at a load of 1.5 N with dry sliding. Although minor hurt on corrosion resistance was caused, significant improvement of wear resistance was obtained after tempering treatment of the coating.
基金Project(KJ070602)supported by Program of Applied Science Foundation of Chongqing Education Committee,ChinaProject(KF0604)supported by the Open Foundation of Key Laboratory of Low Dimensional Materials&Application Technology(Xiangtan University),Ministry of Education,China
文摘A novel Ni-P-SiC composite coating was prepared by electroless plating in order to improve the corrosion capacity and wear resistance of AZ91D magnesium alloy.The influence of pH values on deposition rates and properties of the coatings was studied.The microstructure and phase structure of the Ni-P-SiC coatings were analyzed by scanning electron microscopy(SEM)and X-ray diffractometry(XRD).The corrosion and wear resistance performances of the coatings were also investigated through electrochemical technique and pin-on-disk tribometer,respectively.The results indicate that the composite coating is composed of Ni, P and SiC.It exhibits an amorphous structure and good adhesion to the substrate.The coatings have higher open circuit potential than that of the substrate.The composite coating obtained at pH value of 5.2 possesses optimal integrated properties,which shows similar corrosion resistance and ascendant wear resistance properties to the substrate.
基金Project(50673028)supported by the National Natural Science Foundation of ChinaProject(04020090)supported by Guangdong NaturalScience Foundation,China
文摘Polymeric nano-film on the surface of Mg-Mn-Ce magnesium alloy was fabricated by polymer plating of 6-dihexylamino-1,3,5-triazine-2,4-dithiol monosodium(DHN) to improve its corrosion resistance.The electrochemical reaction process was analyzed by cyclic voltammetry and two obvious peaks of oxidation reaction were observed.The static contact angle of distilled water on polymer-plated surface can be up to 106.3°while on the blank surface it is 45.8°.Potentiodynamic polarization results show that the polymeric film can increase the corrosion potential from -1.594 V vs SCE for blank to -0.382 V vs SCE.The results of electrochemical impedance spectroscopy indicate that the charge transfer resistances of blank and polymer-plated Mg-Mn-Ce alloy are 485Ω·cm^2 and 2 717Ω·cm^2,respectively.The method of polymer plating can provide a novel approach for fabricating hydrophobic film on Mg-Mn-Ce alloy surface and improving its anti-corrosion property.
文摘Electroless nickel-plating on die cast magnesium alloy AZ91D was investigated. Growth of the electroless nickel-plating coating was characterized using scanning electron microscopy. Corrosion resistance of the coating was evaluated by open circuit potential and potentiodynamic polarization curves in 3.5%(mass fraction) NaCl solution. The results show that plating deposition is initiated on the crevices and then spread onto primary α phase. The corrosion potentials for die cast magnesium alloy AZ91D and nickel-plating coating are about -1.45 V and -0.36 V(vs. SCE),respectively. No discoloration,cracks,blisters,or peeling appear by heat-quench test. The results show that the corrosion potential of Ni-P coating is increased by 1 000 mV and corrosion resistance for die cast magnesium alloy AZ91D is improved. The adhesion between the coating and the substrate is excellent. Electroless nickel plating is a promising method to enhance magnesium alloys resistance for attacking.
基金Project (2006031117-04) supported by the Key Technique Item of Shanxi Province, China
文摘An electroless Ni-P plating treatment was applied on AZ91D magnesium alloy to improve its corrosion resistance. Optimum pretreatment conditions and optimum bath of electroless nickel plating for magnesium alloy were found through many experiments. In order to avoid bother of pre-plating medium layer, a set of procedure of direct electroless Ni-P under the acid condition was investigated. The properties of the coating with 10% phosphorus were investigated. The results show that a coating with high hardness, low porosity and good adhesive strength is obtained. X-ray diffraction patterns show that the structure of the coating is an amorphous phase. After annealing at 400℃, the amorphous phase of Ni-P is transformed to crystalline phases, and some intermetallics as Ni3P and Ni5P2 are deposited from Ni-P solid solution along with an enhancing hardness from Hv 450 to Hv 910.
基金Project (202113191) supported by the Science Fund of Education Office of Liaoning Province, ChinaProject supported by the Director Fund of Experimental Centre of Shenyang Normal University, China
文摘Electroplating zinc coating as transition layer of electroless nickel plating on AM60 magnesium alloys was investigated. The zinc film can be deposited in a pyrophosphate bath at 50-60℃under current density of 0.5-1.5 A/dm2. A new fore treatment technology was applied by acid cleaning with a solution containing molybdate and phosphorous acid, by alkaline cleaning in a bath containing molybdate and sodium hydroxide. The subsequent electroless plating was carried out in nickel sulfate bath. The SEM observation shows that the deposition is uniform and compact. The polarization curve measurements show that the corrosion potential of the zinc plating in 3.5% NaCl is about -1.3 V(vs SCE) which is noble than that of magnesium substrate. The zinc electroplating can be applied as the pretreatment process for electroless nickel plating on magnesium alloys.
基金Project(2007CB613705)supported by the National Key Basic Research ProgramProject(2006BAE04B05-2)supported by the NationalKey Technology R&D Program of China
文摘Magnesium alloys covered with metal coating display excellent corrosion resistance,wear resistance,conductivity and electromagnetic shielding properties.The electroless plating Ni-P as bottom layer following the electroplating nickel as surface layer on AZ91D magnesium alloy was investigated.The coating surface morphology was observed with SEM and the structure was analyzed with XRD.Electrochemical tests and salt spray tests were carried out to study the corrosion resistance.The experimental results indicate that the dual coating is uniform,compact and pore-free.The adhesion strength between magnesium alloy substrate and electroless plating Ni-P bottom layer and electroplating nickel surface layer is perfect.The corrosion resistance of AZ91D magnesium alloy is greatly improved after being protected with the dual coating.
基金The authors gratefully acknowledge the sponsorship from the State Key Program of National Natural Science Foundation of China(Nos.U1760201,52034005)the National Natural Science Foundation of China(No.51974220)+2 种基金the Key Research and Development Program of Shaanxi Province,China(Nos.2020ZDLGY13-06,2017ZDXM-GY-037)the Innovation Capacity Support Project of Shaanxi Province,China(No.2020KJXX-077)the Education Department Foundation of Shaanxi Province,China(No.17JK0430).