The Effects of heat treatment temperature on the hardness,wear resistance and structure of the amorphous Ni-W-P-SiC composite coatings have been investigated.The results show that Ni-W-P-SiC composite coatings are amo...The Effects of heat treatment temperature on the hardness,wear resistance and structure of the amorphous Ni-W-P-SiC composite coatings have been investigated.The results show that Ni-W-P-SiC composite coatings are amorphous under 300℃, partially crystalline at 300-400℃,and crystalline when heat treatment temperature reaches 400℃,the crystals being fine Ni3P phase particles.The hardness,wear resistance and the crystallization temperature of the composite coatings increase when an additive is added into the bath.The hardness and wear resistance of the coatings increase with increasing heat treatment temperature,and they will reach their peak values when the heat treatment temperature reaches 400℃.Corrosion experiment indicates that the corrosion resistance of amorphous Ni-W-P-SiC composite coatings in various kinds of corrosive media except nitric acid is better than that of stainless steel 1Cr18Ni9Ti.Scanning electron microscopy observation shows that the additive has no effect on the surface appearance of the coatings,but the current density and the pH value have considerable effects on the surface appearance.展开更多
Cathodic deposition current density of the composite coatings increases when SiC par-ticles and rare earth (RE) were added in the bath, which is profitable for Ni- W-P alloy to deposit in the cathod, forming Ni-W-P-Si...Cathodic deposition current density of the composite coatings increases when SiC par-ticles and rare earth (RE) were added in the bath, which is profitable for Ni- W-P alloy to deposit in the cathod, forming Ni-W-P-SiC and RE-Ni-W-P-SiC composite coatings. On the contrary, the addition of PTFE in the bath decreases cathodic deposition current density of the coatings. The current density increases a little when the amount of RE is 7-9g/l; however, the current density increases greatly when the amount of RE is increased to 11-13g/l. Bui ij the amount of RE is raised further, the current density decreases. Hardness and wear resistance of RE-Ni-W-P-SiC composite coating have been studied, and the results show that the hardness and wear resistance of RE-Ni-W-P-SiC composite coating increase with increasing heat treatment tempera-ture, which reach peak values at 400℃; while the hardness and wear resistance of the coating decrease with the rise of heat treated temperature continuously.展开更多
The effects of pulse frequency f and duty cycle r on the deposition rate, composition, morphology, and hardness of pulse electrodeposited RE （rare earth）-Ni-W-P-SiC composite coatings have been studied. The results ...The effects of pulse frequency f and duty cycle r on the deposition rate, composition, morphology, and hardness of pulse electrodeposited RE （rare earth）-Ni-W-P-SiC composite coatings have been studied. The results indicate that pulse current can improve the deposition rate of RE-Ni-W-P-SiC composite coatings; W, P, and SiC contents in the coating decrease with the increase of pulse frequency and reach the lowest value at f = 33Hz, whereas the RE content in the composite coatings increases with the increase of pulse frequency. SiC content decreases with the increase of duty cycle, W content reaches the lowest value, and P content reaches the highest value at r = 0.4; pulse current and RE can lead to smaller size of the crystalline grains; however, the effects of different pulse frequency and duty cycle on the morphologies of RE-Ni-W-P-SiC composite coatings are not obvious. The hardness of RE-Ni-W-P-SiC composite coatings is the highest when the duty cycle is at 0.6 and 0.8 and pulse frequency is at 50Hz. At the same pulse frequency, the hardness of RE-Ni-W-P-SiC composite coatings at r= 0.8 is higher than that at r= 0.6.展开更多
研究了化学镀Ni W P SiC复合镀层的孔隙率。结果表明,镀液温度和施镀时间对镀层孔隙率的影响较大,在镀液T=80℃、施镀时间t=2.5h时所得镀层的孔隙率较小;热处理温度和时间对镀层孔隙率有一定影响,热处理温度为400℃,时间为3h时,镀层... 研究了化学镀Ni W P SiC复合镀层的孔隙率。结果表明,镀液温度和施镀时间对镀层孔隙率的影响较大,在镀液T=80℃、施镀时间t=2.5h时所得镀层的孔隙率较小;热处理温度和时间对镀层孔隙率有一定影响,热处理温度为400℃,时间为3h时,镀层孔隙率最小。展开更多
The oxidation of the Electrodeposited RE-Ni-W-P-SiC Composite materials at high temperature is investigated. The results show that during high temperature oxidation the relationship between the mass change of pure Ni,...The oxidation of the Electrodeposited RE-Ni-W-P-SiC Composite materials at high temperature is investigated. The results show that during high temperature oxidation the relationship between the mass change of pure Ni, Ni-W-P, Ni-W-P-SiC or RE-Ni-W-P-SiC coatings and the oxidation time follows a mixed curve, i.e. it is approximately a linear relationship when the oxidation time is less than 60 mins while it is a power function relationship when the oxidation time is over 60 mins. The order for the oxidation rate of the four coatings is Ni> Ni-W-P> Ni-W-P-SiC>RE-Ni-W-P-SiC. The mass change of Ni-W-P, Ni-W-P-SiC or RE-Ni-W-P-SiC coatings increases exponentially with a rise of oxidation temperature. The high temperature-oxidation resistance of RE-Ni-W-P-SiC composite material is 3-4 times than that of Ni-W-P alloy coating. The cross section morphologies and X-ray diffraction patterns indicate that the high temperature-oxidation resistance of RE-Ni-W-P-SiC composite coating is better than any other coatings.展开更多
Effects of pulse current on properties of electrodeposited RE-Ni-W-P-SiC composite coating were studied. The results show that hardness of the pulse current electrodeposited composite coatings is higher than that of t...Effects of pulse current on properties of electrodeposited RE-Ni-W-P-SiC composite coating were studied. The results show that hardness of the pulse current electrodeposited composite coatings is higher than that of the direct current electrodeposited composite coatings while other parameters are the same. Otherwise, the deposited velocity is higher, and wear resistance and corrosion resistance of the pulse current electrodeposited composite coatings are also improved when the average current density is 10 A/dm2 , pulse frequency is 800 Hz and duty ratio is 1: 5. The hardness of the coating as-deposited is HV500 - 700, and it reaches HV1300 after heat treatment at 400 ℃ for 1 h.展开更多
Immersion experiment results show that corrosion rate of the as deposited RE Ni W P SiC composite coating in HCl solutions increases with the rise of HCl concentration. On the contrary, the corrosion rate of the compo...Immersion experiment results show that corrosion rate of the as deposited RE Ni W P SiC composite coating in HCl solutions increases with the rise of HCl concentration. On the contrary, the corrosion rate of the composite coating after heat treatment decreases with increasing HCl concentration. The corrosion rates of the composite coatings in as deposited state and after heat treatment in H 2SO 4 and H 3PO 4 solutions respectively decrease with the rise of H 2SO 4 and H 3PO 4 concentrations. The corrosion rate of the composite coating as deposited in FeCl 3 solutions decreases with increasing FeCl 3 concentration, while the rate of the composite coating after heat treatment increases with the rise of FeCl 3 concentration. The corrosion rate of 316L stainless steel in the corrosion media of H 2SO 4, HCl, H 3PO 4 and FeCl 3 solutions at different concentrations increases with rising concentration. In addition, the corrosion rate of 316L stainless steel in the corrosion media of H 2SO 4, HCl, H 3PO 4 and FeCl 3 solutions respectively is much greater than that of the RE Ni W P SiC composite coating as deposited and after heat treatment in the same corrosion media. [展开更多
研究了RE Ni W P SiC复合镀层的脉冲电沉积工艺。结果表明:RE Ni W P SiC镀层的脉冲电沉积速率比直流电沉积大,脉冲镀层的耐蚀性和硬度都优于直流镀层,耐蚀性优于1Cr18Ni9Ti不锈钢;脉冲频率和占空比对镀层的沉积速率、镀层成分以及镀层...研究了RE Ni W P SiC复合镀层的脉冲电沉积工艺。结果表明:RE Ni W P SiC镀层的脉冲电沉积速率比直流电沉积大,脉冲镀层的耐蚀性和硬度都优于直流镀层,耐蚀性优于1Cr18Ni9Ti不锈钢;脉冲频率和占空比对镀层的沉积速率、镀层成分以及镀层的性能都有很大影响。脉冲镀层比直流镀层的结晶更细密,表面更光滑平整。稀土的加入有利于细化晶粒。展开更多
研究了脉冲电沉积Ni W P SiC复合电镀工艺。研究表明 :Ni W P SiC镀层的脉冲电沉积速率比直流电沉积的大 ,脉冲镀层的耐蚀性和硬度都优于直流镀层 ,耐蚀性还优于 1Cr18Ni9Ti不锈钢 ;脉冲频率和占空比对镀层的沉积速率、镀层成分以及镀...研究了脉冲电沉积Ni W P SiC复合电镀工艺。研究表明 :Ni W P SiC镀层的脉冲电沉积速率比直流电沉积的大 ,脉冲镀层的耐蚀性和硬度都优于直流镀层 ,耐蚀性还优于 1Cr18Ni9Ti不锈钢 ;脉冲频率和占空比对镀层的沉积速率、镀层成分以及镀层的性能都有很大的影响。SEM观察表明 ,脉冲镀层比直流镀层的结晶更细密 ,表面更光滑平整。展开更多
Corrosion rate and anode polarization curves of electrodeposited RE-Ni-W-P-SiC-PTFE composite coating in various concentrations of phosphoric and ferric chloride were researched. The results show that corrosion rate o...Corrosion rate and anode polarization curves of electrodeposited RE-Ni-W-P-SiC-PTFE composite coating in various concentrations of phosphoric and ferric chloride were researched. The results show that corrosion rate of the composite coatings increases with the increasing concentrations of phosphoric and ferric chloride, and reaches the maximum value when phosphoric concentration is 40% and ferric chloride concentration is 20% (mass fraction, the same below if not mentioned). Anode polarization curves of the composite coatings show that anode polarization current density of the composite coatings heat-treated at 200 ℃ or 500 ℃ is lower than that of other coatings heat-treated at 300 ℃ or 400 ℃, which displays that the composite coatings heat-treated at 200 ℃ or 500 ℃ have better corrosion resistance. Besides, corrosion resistance of the composite coating heat-treated at 500 ℃ is better than that as deposited and RE-Ni-W-P-SiC composite coating heat-treated at 400 ℃, and is also better than that of 316L stainless steel.展开更多
为了进一步掌握电沉积RE Ni W P SiC复合材料镀层的阴极过程 ,采用电位线性扫描测绘法、镀液pH值测定法研究了复合镀层阴极过程 ,结果表明 ,当镀液中加入SiC微粒和稀土后 ,复合材料的阴极沉积电流密度增加 ,有利于Ni W P合金在阴极沉积 ...为了进一步掌握电沉积RE Ni W P SiC复合材料镀层的阴极过程 ,采用电位线性扫描测绘法、镀液pH值测定法研究了复合镀层阴极过程 ,结果表明 ,当镀液中加入SiC微粒和稀土后 ,复合材料的阴极沉积电流密度增加 ,有利于Ni W P合金在阴极沉积 ,并形成Ni W P SiC和RE Ni W P SiC复合材料。而镀液中加入PTFE后却降低了复合材料镀层的阴极沉积电流密度。当稀土的添加量为 7～ 9g/L时 ,复合材料镀层的阴极沉积电流密度增加并不明显 ;随着稀土添加量的增加 ,复合材料镀层的阴极沉积电流密度增加较明显 ,当添加量达到 11～ 13g/L时 ,镀层的阴极沉积电流密度增加并达到最大值 ;若进一步增加稀土用量 ,则阴极沉积电流密度有所下降。如此可以加大SiC和RE对阴极电沉积的影响。展开更多
文摘The Effects of heat treatment temperature on the hardness,wear resistance and structure of the amorphous Ni-W-P-SiC composite coatings have been investigated.The results show that Ni-W-P-SiC composite coatings are amorphous under 300℃, partially crystalline at 300-400℃,and crystalline when heat treatment temperature reaches 400℃,the crystals being fine Ni3P phase particles.The hardness,wear resistance and the crystallization temperature of the composite coatings increase when an additive is added into the bath.The hardness and wear resistance of the coatings increase with increasing heat treatment temperature,and they will reach their peak values when the heat treatment temperature reaches 400℃.Corrosion experiment indicates that the corrosion resistance of amorphous Ni-W-P-SiC composite coatings in various kinds of corrosive media except nitric acid is better than that of stainless steel 1Cr18Ni9Ti.Scanning electron microscopy observation shows that the additive has no effect on the surface appearance of the coatings,but the current density and the pH value have considerable effects on the surface appearance.
基金The project was supported by Yunnan Provincial Natural Science Foundation (95B11-5).
文摘Cathodic deposition current density of the composite coatings increases when SiC par-ticles and rare earth (RE) were added in the bath, which is profitable for Ni- W-P alloy to deposit in the cathod, forming Ni-W-P-SiC and RE-Ni-W-P-SiC composite coatings. On the contrary, the addition of PTFE in the bath decreases cathodic deposition current density of the coatings. The current density increases a little when the amount of RE is 7-9g/l; however, the current density increases greatly when the amount of RE is increased to 11-13g/l. Bui ij the amount of RE is raised further, the current density decreases. Hardness and wear resistance of RE-Ni-W-P-SiC composite coating have been studied, and the results show that the hardness and wear resistance of RE-Ni-W-P-SiC composite coating increase with increasing heat treatment tempera-ture, which reach peak values at 400℃; while the hardness and wear resistance of the coating decrease with the rise of heat treated temperature continuously.
文摘The effects of pulse frequency f and duty cycle r on the deposition rate, composition, morphology, and hardness of pulse electrodeposited RE （rare earth）-Ni-W-P-SiC composite coatings have been studied. The results indicate that pulse current can improve the deposition rate of RE-Ni-W-P-SiC composite coatings; W, P, and SiC contents in the coating decrease with the increase of pulse frequency and reach the lowest value at f = 33Hz, whereas the RE content in the composite coatings increases with the increase of pulse frequency. SiC content decreases with the increase of duty cycle, W content reaches the lowest value, and P content reaches the highest value at r = 0.4; pulse current and RE can lead to smaller size of the crystalline grains; however, the effects of different pulse frequency and duty cycle on the morphologies of RE-Ni-W-P-SiC composite coatings are not obvious. The hardness of RE-Ni-W-P-SiC composite coatings is the highest when the duty cycle is at 0.6 and 0.8 and pulse frequency is at 50Hz. At the same pulse frequency, the hardness of RE-Ni-W-P-SiC composite coatings at r= 0.8 is higher than that at r= 0.6.
文摘The oxidation of the Electrodeposited RE-Ni-W-P-SiC Composite materials at high temperature is investigated. The results show that during high temperature oxidation the relationship between the mass change of pure Ni, Ni-W-P, Ni-W-P-SiC or RE-Ni-W-P-SiC coatings and the oxidation time follows a mixed curve, i.e. it is approximately a linear relationship when the oxidation time is less than 60 mins while it is a power function relationship when the oxidation time is over 60 mins. The order for the oxidation rate of the four coatings is Ni> Ni-W-P> Ni-W-P-SiC>RE-Ni-W-P-SiC. The mass change of Ni-W-P, Ni-W-P-SiC or RE-Ni-W-P-SiC coatings increases exponentially with a rise of oxidation temperature. The high temperature-oxidation resistance of RE-Ni-W-P-SiC composite material is 3-4 times than that of Ni-W-P alloy coating. The cross section morphologies and X-ray diffraction patterns indicate that the high temperature-oxidation resistance of RE-Ni-W-P-SiC composite coating is better than any other coatings.
文摘Effects of pulse current on properties of electrodeposited RE-Ni-W-P-SiC composite coating were studied. The results show that hardness of the pulse current electrodeposited composite coatings is higher than that of the direct current electrodeposited composite coatings while other parameters are the same. Otherwise, the deposited velocity is higher, and wear resistance and corrosion resistance of the pulse current electrodeposited composite coatings are also improved when the average current density is 10 A/dm2 , pulse frequency is 800 Hz and duty ratio is 1: 5. The hardness of the coating as-deposited is HV500 - 700, and it reaches HV1300 after heat treatment at 400 ℃ for 1 h.
文摘Immersion experiment results show that corrosion rate of the as deposited RE Ni W P SiC composite coating in HCl solutions increases with the rise of HCl concentration. On the contrary, the corrosion rate of the composite coating after heat treatment decreases with increasing HCl concentration. The corrosion rates of the composite coatings in as deposited state and after heat treatment in H 2SO 4 and H 3PO 4 solutions respectively decrease with the rise of H 2SO 4 and H 3PO 4 concentrations. The corrosion rate of the composite coating as deposited in FeCl 3 solutions decreases with increasing FeCl 3 concentration, while the rate of the composite coating after heat treatment increases with the rise of FeCl 3 concentration. The corrosion rate of 316L stainless steel in the corrosion media of H 2SO 4, HCl, H 3PO 4 and FeCl 3 solutions at different concentrations increases with rising concentration. In addition, the corrosion rate of 316L stainless steel in the corrosion media of H 2SO 4, HCl, H 3PO 4 and FeCl 3 solutions respectively is much greater than that of the RE Ni W P SiC composite coating as deposited and after heat treatment in the same corrosion media. [
文摘研究了RE Ni W P SiC复合镀层的脉冲电沉积工艺。结果表明:RE Ni W P SiC镀层的脉冲电沉积速率比直流电沉积大,脉冲镀层的耐蚀性和硬度都优于直流镀层,耐蚀性优于1Cr18Ni9Ti不锈钢;脉冲频率和占空比对镀层的沉积速率、镀层成分以及镀层的性能都有很大影响。脉冲镀层比直流镀层的结晶更细密,表面更光滑平整。稀土的加入有利于细化晶粒。
文摘研究了脉冲电沉积Ni W P SiC复合电镀工艺。研究表明 :Ni W P SiC镀层的脉冲电沉积速率比直流电沉积的大 ,脉冲镀层的耐蚀性和硬度都优于直流镀层 ,耐蚀性还优于 1Cr18Ni9Ti不锈钢 ;脉冲频率和占空比对镀层的沉积速率、镀层成分以及镀层的性能都有很大的影响。SEM观察表明 ,脉冲镀层比直流镀层的结晶更细密 ,表面更光滑平整。
基金Project([2002]24) supported by the National Development and Reform Commission of China
文摘Corrosion rate and anode polarization curves of electrodeposited RE-Ni-W-P-SiC-PTFE composite coating in various concentrations of phosphoric and ferric chloride were researched. The results show that corrosion rate of the composite coatings increases with the increasing concentrations of phosphoric and ferric chloride, and reaches the maximum value when phosphoric concentration is 40% and ferric chloride concentration is 20% (mass fraction, the same below if not mentioned). Anode polarization curves of the composite coatings show that anode polarization current density of the composite coatings heat-treated at 200 ℃ or 500 ℃ is lower than that of other coatings heat-treated at 300 ℃ or 400 ℃, which displays that the composite coatings heat-treated at 200 ℃ or 500 ℃ have better corrosion resistance. Besides, corrosion resistance of the composite coating heat-treated at 500 ℃ is better than that as deposited and RE-Ni-W-P-SiC composite coating heat-treated at 400 ℃, and is also better than that of 316L stainless steel.
文摘为了进一步掌握电沉积RE Ni W P SiC复合材料镀层的阴极过程 ,采用电位线性扫描测绘法、镀液pH值测定法研究了复合镀层阴极过程 ,结果表明 ,当镀液中加入SiC微粒和稀土后 ,复合材料的阴极沉积电流密度增加 ,有利于Ni W P合金在阴极沉积 ,并形成Ni W P SiC和RE Ni W P SiC复合材料。而镀液中加入PTFE后却降低了复合材料镀层的阴极沉积电流密度。当稀土的添加量为 7～ 9g/L时 ,复合材料镀层的阴极沉积电流密度增加并不明显 ;随着稀土添加量的增加 ,复合材料镀层的阴极沉积电流密度增加较明显 ,当添加量达到 11～ 13g/L时 ,镀层的阴极沉积电流密度增加并达到最大值 ;若进一步增加稀土用量 ,则阴极沉积电流密度有所下降。如此可以加大SiC和RE对阴极电沉积的影响。
