共查询到17条相似文献,搜索用时 15 毫秒
1.
《Ceramics International》2022,48(4):5091-5099
The impact of the addition of TiO2 nanoparticles and nanowires on the morphology, phase characteristics, contact angle, and electrochemical performance of chemically bonded phosphate ceramic coatings (CBPCs) was investigated. The chemical composition and surface morphology of the TiO2 nanoparticle and nanowire modified with and without (heptadecafluoro-1,1,2,2-tetradecyl) trimethoxysilane were characterized. Results indicated that the hydrophobic –CF2– and –CF3 groups were successfully introduced into the TiO2 nanoparticles and nanowires after modification. Corrosion resistance of CBPCs with TiO2 was evidently improved compared with that without TiO2. Such improvement was mainly due to the combined effects of low surface energy materials and micro/nano structures. In addition, CBPCs with TiO2 nanowires exhibited higher hydrophobicity and corrosion resistance than those with TiO2 nanoparticles because of the special columnar structure of the nanowires. 相似文献
2.
Bian Da Liu Yaxuan Aradhyula Thirumala Vasu Guo Yongxin Tang Hao Zhao Yongwu Wang Yongguang 《Ceramics International》2021,47(11):15722-15731
To enhance the tribocorrosion properties of chemically bonded phosphate ceramic coating (CBPCC), GO-ZnO was prepared and added into CBPCC. And the tribocorrosion behaviour of CBPCC was investigated. Results show that, with the introduction of GO-ZnO, the open circuit potential of CBPCC shifts in a positive direction and corrosion current density decreases. In addition, the total material loss, the total mechanical wear loss and the total electrochemical corrosion loss of CBPCC all decrease with the increase of GO-ZnO. The wear track of CBPCC after tribocorrosion without GO-ZnO is rough and porous, while the wear track becomes smooth and dense with the incorporation of GO-ZnO. The material in wear track is anchored by GO-ZnO due to the strong bond between GO-ZnO and CBPCC, which decreases the wear loss. Because of the extra force from the tribocorrosion experiment, the material anchored by GO-ZnO forms to a dense structure which prevents electrolyte diffusion into CBPCC. Moreover, GO-ZnO can block the electrolyte diffusion pathway and make it more tortuous. The resistance to the electrolyte diffusion decreases the corrosion current density and the increased wear loss due to electrochemical corrosion. 相似文献
3.
Mazen Alshaaer 《International Journal of Applied Ceramic Technology》2021,18(2):319-331
The microstructure of a wollastonite chemically bonded phosphate ceramic (WCPC) and its long-term stability can be characterized in terms of functions over time and at intermediate temperatures (RT, 40°C, 60°C, and 80°C). As seen through SEM images and EDX analysis, the ceramic microstructure comprises brushite, wollastonite and an amorphous heterogeneous phase. Electron backscatter diffraction (EBSD) mapping shows the amorphous phase in this chemically bonded phosphate ceramic to have a uniform distribution of Ca and P elements. The transformation of brushite and the amorphous matrix in its solid state to a more stable CaP phase takes place over a long period. The mechanical performance of the ceramic is therefore improved by thermal aging. Chemical changes are accompanied by denser, more stable phases leading to increased stiffness. The primary disadvantage associated with using this new material in construction would be its relatively high shrinkage as a result of chemical and physical factors. 相似文献
4.
Rongli Xu Da Bian Yongwu Zhao Xiaoyan Xu Yaxuan Liu Wenlei Zhou 《International Journal of Applied Ceramic Technology》2020,17(3):1010-1016
To improve the wear resistance of the chemically bonded phosphate ceramic coatings, MWCNTs are selected as the reinforcement after the modification. The high temperature wear experiment is carried out to investigate the wear behavior of the coatings with different temperatures. The results suggest that, when the temperature is below 500℃, MWCNTs can decrease friction coefficient, and the lowest friction coefficient is about 0.28, but MWCNTs lose the lubricant function at 500℃ and the friction coefficient keeps at the level of ~ 0.68. In addition, the wear resistance of coatings is improved with the introduction of MWCNTs at 100℃ and 300℃ (the wear rate is below 15X10-3mm3/Nm), but keeps similar level at 500℃ (the wear rate is ~ 22 × 10−3mm3/Nm). Besides, the wear mechanism of the coatings reinforced by MWCNTs is also investigated based on the wear behavior and microstructural characterizations. MWCNTs improve the fracture toughness by preventing the crack generation and forming the bridge when crack occurs, which leads to smooth wear tracks and good wear resistance of coatings. The coatings with MWCNTs achieve poor wear resistance at 500℃ because MWCNTs lose their strength and resistance to fatigue by oxidizing. 相似文献
5.
《Ceramics International》2022,48(2):1926-1935
MXenes – In recent decades, great attention has been paid to the fast-growing two-dimensional (2D) transition metal carbides and nitrides, in terms of their prominent mechanical and electrical properties. The tribological essence of MXene has not yet been entirely investigated, although researches on MXene were conducted in all aspects of its applications. Hence, a newly compound 2D MXene (Ti3C2Tx) is exploited to reinforce the wear resistance of the chemically bonded silicate ceramic coatings, which are utilized to protect component surfaces under severe conditions. The structural features, hardness, and tribological behaviors of the targeted coatings are investigated and analyzed. Results show that the micro-hardness of the coatings increases to 156.9 HV0.5 when added 1.2 wt% MXene. The increment of microhardness extraordinarily reaches 33.3%, compared with the original. The coating with 1.2 wt% MXene also indicates a 31.6% decrement of the coefficient of friction (COF) and a 73% reduction of the wear rate respectively. Furthermore, fatigue is found to be the main reason of the wear mechanism, through exploring the surface morphologies of wear traces and counterpart balls. 相似文献
6.
Xu Rongli Da Bian Thirumala Vasu Aradhyula Murthy Chavali Yongwu Zhao 《International Journal of Applied Ceramic Technology》2019,16(3):923-930
To improve the corrosion resistance of the chemically bonded phosphate ceramic coating, the MWCNTs are selected as the reinforcement after the modification. Through the analysis of TEM, Raman, XRD, and FTIR, it can be shown that MWCNTs are modified with carboxyl groups and the surfactant after treatment, and show good dispersion. In addition, the electrochemical experiments were carried out with 3.5 wt% NaCl solution to investigate the corrosion behavior of the coatings. The results suggest that the corrosion resistance of coatings is improved with the introduction of MWCNTs and the corrosion resistance increases with the increase in MWCNTs. Besides, the corrosion mechanism of MWCNTs reinforced coating corrosion resistance was also investigated based on the corrosion behavior and microstructural characterizations. The gel strength is improved with the addition of MWCNTs because of its strong strength, which can prevent crack occurring and form the bridge when crack happens. Therefore, H2O, O2, and Cl− can be prevented from reaching to the substrate, which leads to good corrosion resistance. 相似文献
7.
Hao Tang Yaxuan Liu Da Bian Yongxin Guo Yongwu Zhao 《International Journal of Applied Ceramic Technology》2020,17(6):2612-2621
In this paper, a solvothermal method is used to prepare nano-sized zinc oxide-graphene oxide (ZnO–GO) hybrid, and the ZnO–GO hybrid is characterized by X-ray diffraction analysis, Raman, Fourier transform infrared spectroscopy, and scanning electron microscopy. In addition, chemically bonded phosphate ceramics coatings with different content of ZnO–GO hybrid are prepared on the stainless steel through the sol-gel method. The corrosion performance of the coatings is evaluated by electrochemical properties and the analysis of the surface and cross morphology of the coating. Results indicate ZnO–GO hybrid significantly enhances the compactness and corrosive behavior of the coating because the overlapping structure of GO flake improves the barrier performance of the coating. Besides, ZnO nanoparticles on the surface of GO can react with aluminum dihydrogen phosphate binder, in that case the adhesion between GO and the coating is improved. 相似文献
8.
金属陶瓷涂层耐蚀性能研究 总被引:5,自引:0,他引:5
采用溶胶-凝胶浸渍提拉法在不锈钢、纯铜及铝合金基体上制备具有保护性的SiO2、ZrO2、TiO2、Al2O3及SiO2-TiO2陶瓷涂层,利用阳极极化曲线的、循环动电位极曲线、点蚀电位的测量以及三氯化铁和5%硫酸介质中的腐蚀试验研究了所得陶瓷涂层的耐蚀性。结果表明,这些陶瓷涂层能大幅芳提高金属基体在各种腐蚀介的耐蚀性。 相似文献
9.
《Ceramics International》2020,46(12):20448-20455
The objective of this study was to develop chemically bonded phosphate ceramic (CBPC) coatings with relatively low curing temperature, properly prolonged curing time, and enhanced oxidation resistance. The coating was synthesised using aluminium phosphate as binder, surface modified MgOw/MgO as curing agent, and spherical microscaled Al particle as filler. The MgOw/MgO curing agent was surface coated by an Al2O3 layer via sol-gel routes. The Al2O3-coated MgOw/MgO agent facilitated a controllable curing process owing to the sustained-release effect of the surrounding microstructure. The weight loss profiles of all CBPCs with a surface modified curing agent exhibited a quasi-parabolic trend. The curing time decreased with the addition of the curing agent, and the Al2O3-coated MgOw curing agent was more effective owing to the good dispersion and larger particle number/volume percentage. The thermogravimetric and differential scanning calorimetry curves proved that the Al element exhibited similar effect as Mg2+, which could also enhance the curing process via substitution reaction between the basic metal ions with hydrogen in phosphate. Therefore, the addition of Al filler resulted in further curing and densification, exhibiting a decrease in the curing time (30–50 min) and increase in the weight loss (~40%). Proper binder-to-curing agent-to-filler mass (B:C:F) ratio was very important, and the CBPCs with improved surface roughness, hardness, and free of cracks were synthesised at a B:C:F ratio of 10:1:0.05. During oxidation at 800 °C, the Al filler in the CBPCs transformed into a continuous Al2O3 layer, which protected the Ti6Al4V alloy from further oxidation. 相似文献
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11.
Impedance measurements were performed at room temperature in a 0.005 M Na2HPO4 solution on steel and on electrodeposited Zn and Zn–12%Ni before and after phosphating. It was found that potential and impedance parameters (R
ct and C
d) for phosphated materials attained nearly steady values within about 20 min, indicating that this solution did not cause meaningful changes in phosphate coatings and that it could therefore be used for the quality evaluation of these coatings. On scratches in phosphate coatings on Zn or Zn–12%Ni phosphate deposits rapidly formed, probably owing to enhanced dissolution of the locally exposed substrates at the nobler potentials of the coated materials. This demonstrates that damaged coatings can easily recover on Zn substrates in a non-aggressive phosphate solution. It is suggested that the formation of phosphate deposits on bare metal amidst phosphate coatings should be taken into account in the porosity determination by chemical or electrochemical methods. 相似文献
12.
The effects to the structure and electrochemical behavior of zinc phosphate conversion coatings with ethanolamine on magnesium alloy AZ91D 总被引:1,自引:0,他引:1
This paper discussed a zinc phosphate conversion coating formed on magnesium alloy AZ91D from the phosphating bath with varying amounts of ethanolamine (MEA). The effects of MEA on the form, structure, phase composition and electrochemical behavior of the phosphate coatings were examined using an scanning electron microscopy (SEM), X-ray diffraction (XRD) potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Interpretations of the electrical elements of the equivalent circuit were obtained from the SEM structure of the coatings, assumed to be formed of two layers: an outer porous crystal layer and an inner flat amorphous layer. The result showed that adding MEA refined the microstructure of the crystal layer and that the phosphate coating, derived at the optimal content of 1.2 g/L, with the most uniform and compact outer crystal layer provided the best corrosion protection. 相似文献
13.
Masoud Sabzi Saeid Mersagh Dezfuli 《International Journal of Applied Ceramic Technology》2019,16(1):195-210
The effect of deposition of the Al2O3 ceramic film by the aluminizing method on electrochemical responses and corrosion mechanism of copper-based heterostructured coatings was studied. The single layer coatings of Cu and Al2O3 and Cu/Al2O3 double layers were produced using reverse pulsed current electroplating process followed by powder cementation of aluminum on a substrate made of Inconel 600 superalloy. The produced coatings were then characterized using Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD) methods. In order to evaluate the behavior and corrosion mechanism of the produced coatings, potentiodynamic polarization and electrochemical impedance spectroscopy methods were also used in 1 mol/L HCl solution at immersion times of 1, 12, 24, and 48 hours. The results of the study showed that the mechanism of the formation of Cu/Al2O3 copper-based coatings is that in the aluminizing step, first, the diffusion of Al from the surface layers to the interior occurs and then the diffusion of Cu from the plating layer to the exterior takes places. It was also found that the deposition of the Al2O3 ceramic film resulted in the formation of α-Al2O3 and CuAl2O4 phases and increased corrosion resistance in Cu/Al2O3 copper-based coatings at all immersion times and the corrosion mechanism has changed from uniform to localized state. 相似文献
14.
A glasshouse trial with wheat (Triticum aestivum L. cv. Gamenya) in which harvests were taken at intervals up to 24 days has shown that the effectivness of calcined Christmas Island C-grade aluminium-iron phosphate rock (C500) relative to superphosphate remained low. Relative growth rates did not change despite a decrease in the concentration of bicarbonate extractable phosphorus in soil fertilized with superphosphate. Different numerical values of relative effectiveness based on plant yield and phosphorus uptake respectively may be attributed to different internal efficiencies of phosphorus use for the two fertilizers. 相似文献
15.
The protective performance of solvent-borne epoxy/polyamide coatings formulated with zinc phosphate anticorrosion pigment was improved through the addition of 2-mercaptobenzimidazole as an organic corrosion inhibitor. In addition to determining the optimum percentage of mercaptobenzimidazole, the electrochemical impedance spectroscopy data could show the influence of inhibitor concentration on the epoxy behavior within 35 days of immersion in 3.5 wt% NaCl solution. The improved corrosion protection and adhesion strength in the presence of the pigment and inhibitor were connected to the deposition of a protective layer at the coating/substrate interface which might limit active zones for electrochemical reactions. The precipitation was confirmed using electrochemical impedance spectroscopy, polarization curves and SEM/EDX surface analysis. 相似文献
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17.
探讨了耐高温隔热涂料的隔热性与涂层厚度的相关性,利用相关性指导选择适宜的涂层厚度,达到保温隔热的目的。 相似文献