Magnesium(Mg)stands out in temporary biomaterial applications due to its biocompatibility,biodegradability,and low Young’s modulus.However,controlling its corrosion through next-generation polymer-based functional co...Magnesium(Mg)stands out in temporary biomaterial applications due to its biocompatibility,biodegradability,and low Young’s modulus.However,controlling its corrosion through next-generation polymer-based functional coatings is crucial due to the rapid degradation behavior of Mg.In this study,the function of 2D lamellar Ti_(3)C_(2)T_(x)(MXene)in Hydroxyapatite(HA)and Halloysite nanotube(HNT)hybrid coatings in biodegradable poly-(lactic acid)(PLA)was investigated.The morphological and structural characterizations of the coatings on Mg were revealed through HRTEM,XPS,SEM-EDX,XRD,FTIR,and contact angle analyses/tests.Electrochemical in vitro corrosion tests(OCP,PDS,and EIS-Nyquist)were conducted for evaluate corrosion resistance under simulated body fluid(SBF)conditions.The bioactivity of the coatings in SBF have been revealed in accordance with the ISO 23,317 standard.Finally,antibacterial disk diffusion tests were conducted to investigate the functional effect of MXene in coatings.It has been determined that the presence of MXene in the coating increased not only surface wettability(131°,85°,77°,and 74°for uncoated,pH,PHH,and PHH/MXene coatings,respectively)but also increased corrosion resistance(1857.850,42.357,1.593,and 0.085×10^(-6),A/cm^(2) for uncoated,pH,PHH,and PHH/MXene coatings,respectively).It has been proven that the in vitro bioactivity of PLA-HA coatings is further enhanced by adding HNT and MXene,along with SEM morphologies after SBF.Finally,2D lamellar MXene-filled coating exhibits antibacterial behavior against both E.coli and S.aureus bacteria.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-Cr3C2 coating with intermediate layer. Ni-Zn-Al2O3 coatings as interlaye...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-Cr3C2 coating with intermediate layer. Ni-Zn-Al2O3 coatings as interlayers were prepared by low pressure cold spray（LPCS） between NiCr-Cr3C2 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
Three kinds of NiCr-Cr 3C 2 cermet coatings were designed and deposited by the subsonic velocity flame spraying, and their performances of hot corrosion performance were evaluated in comparison with 102G, 20G boiler...Three kinds of NiCr-Cr 3C 2 cermet coatings were designed and deposited by the subsonic velocity flame spraying, and their performances of hot corrosion performance were evaluated in comparison with 102G, 20G boiler tube steel, FeCrAl, NiCrTi, Ni50Cr and NiCrAlMoFe-Cr 3C 2 coatings, which are widely used at present for protection of boiler tubes. Meanwhile,the influence of sealer on the hot corrosion resistance of various coatings and the mechanisms of coating corrosion were explored.展开更多
Arc spraying with the cored wires was applied to deposit FeMnCr/Cr3C2 coatings on low carbon steel substrates, namely FM1, FM2 and FM3. Thermal shock resistances of the coatings were investigated to assess the influen...Arc spraying with the cored wires was applied to deposit FeMnCr/Cr3C2 coatings on low carbon steel substrates, namely FM1, FM2 and FM3. Thermal shock resistances of the coatings were investigated to assess the influence of Cr3C2 content on thermal shock resistance. Characteristics of the coatings under thermal cycling test were studied by optical microscopy, field emission scanning electron microscope （FE-SEM） and energy dispersion spectrum （EDS）, X-ray diffraction （XRD）. The experimental results show that hardness of the coatings increases, bonding strength decreases slightly with increase of the Cr3C2 content of the coatings. As a result, FM2 coating possesses the best thermal shock resistance, attributing to its better thermal expansion matches and wettability than those of FM3 coating, less oxide rate than that of FM1 coating restraining from cracks formation and propagation in coatings.展开更多
Fe-Al/Cr3C2 composite coatings were manufactured using high velocity arc spraying （HVAS） technology. The high temperature erosion, wear and corrosion resistance of the coatings were investigated. The coating propert...Fe-Al/Cr3C2 composite coatings were manufactured using high velocity arc spraying （HVAS） technology. The high temperature erosion, wear and corrosion resistance of the coatings were investigated. The coating properties such as bonding strength, porosity, hardness as well as microstructures were characterized. The results show that the coatings have relatively high heat tremble bond strength, hardness, and typical layer-shaped coatings＇ microstructures. With the rise of temperature, the coating erosion resistance increases too; the impingement angel does effects on erosion properties, and the erosion mechanism changes from ductile to brittle behaviors at 450℃. The coatings have good room temperature wear resistance and relatively good high temperature resistance. The wear mechanism of the coatings is peeling wear behavior. The coatings have excellent high temperature corrosion resistance because of the produce of oxides during corrosion.展开更多
文摘Magnesium(Mg)stands out in temporary biomaterial applications due to its biocompatibility,biodegradability,and low Young’s modulus.However,controlling its corrosion through next-generation polymer-based functional coatings is crucial due to the rapid degradation behavior of Mg.In this study,the function of 2D lamellar Ti_(3)C_(2)T_(x)(MXene)in Hydroxyapatite(HA)and Halloysite nanotube(HNT)hybrid coatings in biodegradable poly-(lactic acid)(PLA)was investigated.The morphological and structural characterizations of the coatings on Mg were revealed through HRTEM,XPS,SEM-EDX,XRD,FTIR,and contact angle analyses/tests.Electrochemical in vitro corrosion tests(OCP,PDS,and EIS-Nyquist)were conducted for evaluate corrosion resistance under simulated body fluid(SBF)conditions.The bioactivity of the coatings in SBF have been revealed in accordance with the ISO 23,317 standard.Finally,antibacterial disk diffusion tests were conducted to investigate the functional effect of MXene in coatings.It has been determined that the presence of MXene in the coating increased not only surface wettability(131°,85°,77°,and 74°for uncoated,pH,PHH,and PHH/MXene coatings,respectively)but also increased corrosion resistance(1857.850,42.357,1.593,and 0.085×10^(-6),A/cm^(2) for uncoated,pH,PHH,and PHH/MXene coatings,respectively).It has been proven that the in vitro bioactivity of PLA-HA coatings is further enhanced by adding HNT and MXene,along with SEM morphologies after SBF.Finally,2D lamellar MXene-filled coating exhibits antibacterial behavior against both E.coli and S.aureus bacteria.
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-Cr3C2 coating with intermediate layer. Ni-Zn-Al2O3 coatings as interlayers were prepared by low pressure cold spray（LPCS） between NiCr-Cr3C2 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.
文摘Three kinds of NiCr-Cr 3C 2 cermet coatings were designed and deposited by the subsonic velocity flame spraying, and their performances of hot corrosion performance were evaluated in comparison with 102G, 20G boiler tube steel, FeCrAl, NiCrTi, Ni50Cr and NiCrAlMoFe-Cr 3C 2 coatings, which are widely used at present for protection of boiler tubes. Meanwhile,the influence of sealer on the hot corrosion resistance of various coatings and the mechanisms of coating corrosion were explored.
文摘Arc spraying with the cored wires was applied to deposit FeMnCr/Cr3C2 coatings on low carbon steel substrates, namely FM1, FM2 and FM3. Thermal shock resistances of the coatings were investigated to assess the influence of Cr3C2 content on thermal shock resistance. Characteristics of the coatings under thermal cycling test were studied by optical microscopy, field emission scanning electron microscope （FE-SEM） and energy dispersion spectrum （EDS）, X-ray diffraction （XRD）. The experimental results show that hardness of the coatings increases, bonding strength decreases slightly with increase of the Cr3C2 content of the coatings. As a result, FM2 coating possesses the best thermal shock resistance, attributing to its better thermal expansion matches and wettability than those of FM3 coating, less oxide rate than that of FM1 coating restraining from cracks formation and propagation in coatings.
文摘Fe-Al/Cr3C2 composite coatings were manufactured using high velocity arc spraying （HVAS） technology. The high temperature erosion, wear and corrosion resistance of the coatings were investigated. The coating properties such as bonding strength, porosity, hardness as well as microstructures were characterized. The results show that the coatings have relatively high heat tremble bond strength, hardness, and typical layer-shaped coatings＇ microstructures. With the rise of temperature, the coating erosion resistance increases too; the impingement angel does effects on erosion properties, and the erosion mechanism changes from ductile to brittle behaviors at 450℃. The coatings have good room temperature wear resistance and relatively good high temperature resistance. The wear mechanism of the coatings is peeling wear behavior. The coatings have excellent high temperature corrosion resistance because of the produce of oxides during corrosion.
