纳米材料因其自身独特性能而备受关注,从而引发了人们对其进行一系列的研究。采用机械合金化法(MA)和粉末冶金法(PM)制备了纳米尺寸和常规尺寸粉末,通过控制温度和压力等因素,利用真空热压烧结炉将两种不同尺寸的Cu-20Co-20Cr-20Ni粉末...纳米材料因其自身独特性能而备受关注,从而引发了人们对其进行一系列的研究。采用机械合金化法(MA)和粉末冶金法(PM)制备了纳米尺寸和常规尺寸粉末,通过控制温度和压力等因素,利用真空热压烧结炉将两种不同尺寸的Cu-20Co-20Cr-20Ni粉末热压成块体合金,并利用电化学测试技术研究了它们在0.5mol·L^(-1)中性Na Cl溶液中的腐蚀行为以及纳米化对其腐蚀行为的影响。结果表明:当Cu-20Co-20Cr-20Ni合金处于0.5mol·L^(-1) Na Cl腐蚀溶液中时,纳米尺寸Cu-20Co-20Cr-20Ni合金较相应的常规尺寸合金自腐蚀电位发生正移,电荷传递电阻变大,腐蚀电流密度减小。可见,晶粒细化导致Cu-20Co-20Cr-20Ni合金的耐腐蚀性能增强。展开更多
The electrochemical corrosion behavior of the two Cu-40Ni-20Cr alloys prepared by conventional casting(CA) and mechanical alloying(MA) with the different grain sizes was studied by using open-circuit potential(OCP), p...The electrochemical corrosion behavior of the two Cu-40Ni-20Cr alloys prepared by conventional casting(CA) and mechanical alloying(MA) with the different grain sizes was studied by using open-circuit potential(OCP), potentiodynamic polarization and electrochemical impedance spectroscopy(EIS) methods in solutions containing chloride ions. The results show that the free corrosion potentials of the two alloys move towards negative values, corrosion currents increase and therefore corrosion rates become faster with the increase of chloride ion concentrations. EIS plots of CACu-40Ni-20Cr alloy are composed of single capacitive loop, while EIS plots of MACu-40Ni-20Cr alloy are composed of double capacitive loops in solution containing lower chloride ion concentrations. EIS plots of the two alloys have Warburg impedance with the increase of chloride ion concentrations. Corrosion rates of MACu-40Ni-20Cr alloy become faster than those of CACu-40Ni-20Cr alloy obviously in solutions containing the same chloride ion concentrations because MACu-40Ni-20Cr alloy is able to produce large concentrations of grain boundaries in the course of reduction in grain size by mechanical alloying.展开更多
研究了Cu Ni Si Cr合金在时效过程中 ,析出与再结晶的交互作用及其对合金性能的影响。研究结果表明 ,形变使合金时效析出相更加细小、弥散 ,析出对再结晶的形核和长大过程产生阻碍作用。在再结晶的形成和长大过程中 ,析出相在晶界前沿...研究了Cu Ni Si Cr合金在时效过程中 ,析出与再结晶的交互作用及其对合金性能的影响。研究结果表明 ,形变使合金时效析出相更加细小、弥散 ,析出对再结晶的形核和长大过程产生阻碍作用。在再结晶的形成和长大过程中 ,析出相在晶界前沿快速粗化或重新溶解 ,并在再结晶区域中重新析出 ,导致更加弥散的析出相分布。展开更多
The thermogravimetric analysis of a ternary Cu-25Ni-30Cr alloy prepared by conventional casting was performed in 0.1MPa pure O2 at 700-800℃. The results show that the alloy is composed of three phases, where the ...The thermogravimetric analysis of a ternary Cu-25Ni-30Cr alloy prepared by conventional casting was performed in 0.1MPa pure O2 at 700-800℃. The results show that the alloy is composed of three phases, where the phase with the largest copper and lowest chromium content forms the matrix, while the other two, much richer in chromium, form a dispersion of isolated particles. At variance with another three-phase Cu-20Ni-20Cr alloy, which forms complex scales containing the oxides of the various components and double oxides plus an irregular region composed of alloy and oxides, the present alloy can form a very irregular but continuous chromia layer at the base of the mixed internal region, producing a gradual decrease of the oxidation rate down to very low values. A larger chromium content needed to form chromia layer for a ternary three-phase alloy is attributed to the limitations to the diffusion of the alloy components in the metal substrate imposed by their multiphase nature.展开更多
文摘纳米材料因其自身独特性能而备受关注,从而引发了人们对其进行一系列的研究。采用机械合金化法(MA)和粉末冶金法(PM)制备了纳米尺寸和常规尺寸粉末,通过控制温度和压力等因素,利用真空热压烧结炉将两种不同尺寸的Cu-20Co-20Cr-20Ni粉末热压成块体合金,并利用电化学测试技术研究了它们在0.5mol·L^(-1)中性Na Cl溶液中的腐蚀行为以及纳米化对其腐蚀行为的影响。结果表明:当Cu-20Co-20Cr-20Ni合金处于0.5mol·L^(-1) Na Cl腐蚀溶液中时,纳米尺寸Cu-20Co-20Cr-20Ni合金较相应的常规尺寸合金自腐蚀电位发生正移,电荷传递电阻变大,腐蚀电流密度减小。可见,晶粒细化导致Cu-20Co-20Cr-20Ni合金的耐腐蚀性能增强。
基金Project(50771068) supported by the National Natural Science Foundation of ChinaProject(20062049) supported by Natural Science Foundation of Liaoning Province, China
文摘The electrochemical corrosion behavior of the two Cu-40Ni-20Cr alloys prepared by conventional casting(CA) and mechanical alloying(MA) with the different grain sizes was studied by using open-circuit potential(OCP), potentiodynamic polarization and electrochemical impedance spectroscopy(EIS) methods in solutions containing chloride ions. The results show that the free corrosion potentials of the two alloys move towards negative values, corrosion currents increase and therefore corrosion rates become faster with the increase of chloride ion concentrations. EIS plots of CACu-40Ni-20Cr alloy are composed of single capacitive loop, while EIS plots of MACu-40Ni-20Cr alloy are composed of double capacitive loops in solution containing lower chloride ion concentrations. EIS plots of the two alloys have Warburg impedance with the increase of chloride ion concentrations. Corrosion rates of MACu-40Ni-20Cr alloy become faster than those of CACu-40Ni-20Cr alloy obviously in solutions containing the same chloride ion concentrations because MACu-40Ni-20Cr alloy is able to produce large concentrations of grain boundaries in the course of reduction in grain size by mechanical alloying.
文摘研究了Cu Ni Si Cr合金在时效过程中 ,析出与再结晶的交互作用及其对合金性能的影响。研究结果表明 ,形变使合金时效析出相更加细小、弥散 ,析出对再结晶的形核和长大过程产生阻碍作用。在再结晶的形成和长大过程中 ,析出相在晶界前沿快速粗化或重新溶解 ,并在再结晶区域中重新析出 ,导致更加弥散的析出相分布。
文摘The thermogravimetric analysis of a ternary Cu-25Ni-30Cr alloy prepared by conventional casting was performed in 0.1MPa pure O2 at 700-800℃. The results show that the alloy is composed of three phases, where the phase with the largest copper and lowest chromium content forms the matrix, while the other two, much richer in chromium, form a dispersion of isolated particles. At variance with another three-phase Cu-20Ni-20Cr alloy, which forms complex scales containing the oxides of the various components and double oxides plus an irregular region composed of alloy and oxides, the present alloy can form a very irregular but continuous chromia layer at the base of the mixed internal region, producing a gradual decrease of the oxidation rate down to very low values. A larger chromium content needed to form chromia layer for a ternary three-phase alloy is attributed to the limitations to the diffusion of the alloy components in the metal substrate imposed by their multiphase nature.
