Effects of Lanthanum and Cerium Mixed Rare Earth Metal on Abrasion and Corrosion Resistance of AM60 Magnesium Alloy

模板通过析氢集气法、增重法、电化学测试和摩擦磨损性能测试等方法,研究了添加铈镧混合稀土对AM60镁合金耐蚀、耐磨性能的影响。结果表明,在0.35%Na Cl溶液中加入铈镧混合稀土后的AM60镁合金析氢腐蚀电流密度下降、腐蚀电位升高,极化电流密度降低,极化电阻增大、容抗减小,改善了腐蚀电化学性能。其原因归结于混合稀土加入后,细化了镁合金的α相和Mg17Al12相,合金形成的Al2Ce和Al11La3新相抑制了阴极去极化的历程、合金表面形成的Ce O2、La2O3复合阳极氧化膜阻滞了合金的溶解,提高了耐蚀性。加入铈镧混合稀土后,AM60镁合金的摩擦系数较AM60合金明显降低,比磨损率减小,改善了合金的摩擦磨损性能,在0.35%Na Cl溶液中低载荷、滑动速度和短距离滑动时AM60镁合金的主要磨损形式为氧化磨损。     

铈镧混合稀土对AM60镁合金耐蚀耐磨性能的影响(英文)

模板通过析氢集气法、增重法、电化学测试和摩擦磨损性能测试等方法,研究了添加铈镧混合稀土对AM60镁合金耐蚀、耐磨性能的影响。结果表明,在0.35%Na Cl溶液中加入铈镧混合稀土后的AM60镁合金析氢腐蚀电流密度下降、腐蚀电位升高,极化电流密度降低,极化电阻增大、容抗减小,改善了腐蚀电化学性能。其原因归结于混合稀土加入后,细化了镁合金的α相和Mg17Al12相,合金形成的Al2Ce和Al11La3新相抑制了阴极去极化的历程、合金表面形成的Ce O2、La2O3复合阳极氧化膜阻滞了合金的溶解,提高了耐蚀性。加入铈镧混合稀土后,AM60镁合金的摩擦系数较AM60合金明显降低,比磨损率减小,改善了合金的摩擦磨损性能,在0.35%Na Cl溶液中低载荷、滑动速度和短距离滑动时AM60镁合金的主要磨损形式为氧化磨损。     

含Sr、Y和Nd的AM60B镁合金浇注与性能研究

为了提高镁合金的抗高温蠕变性能,把元素Sr和稀土元素Y、Nd加入到AM60B中,采用覆盖剂保护熔炼制备较为致密的AM60B及AM60B (Sr,Y,Nd)合金试样.Sr和稀土元素Y、Nd使AM60B的室温力学性能得到改善.     

热处理和稀土Ce对AZ91D合金性能的影响

研究了热处理和稀土Ce共同作用对AZ91D镁合金组织和性能的影响。结果表明,AZ91D镁合金中加入稀土Ce后,生成了杆状化合物Al4Ce,且网状分布的β-Mg17Al12相变成弥散化分布。随稀土Ce含量的增加,AZ91D镁合金的力学性能和耐蚀性能提高。经T4和T6热处理,杆状化合物Al4Ce的形貌保持不变。T6处理后,加入了稀土Ce合金的力学性能和耐蚀性能比铸态AZ91D镁合金的力学性能和耐蚀性能显著提高。     

稀土元素对ZK60镁合金组织和性能影响的研究现状

简述了稀土元素在镁合金中的作用,重点介绍了Y、Ce、Er、Nd、Dy、Gd、Yb等稀土元素对ZK60镁合金的晶粒尺寸、第二相化合物、室温力学性能以及高温性能的影响,指出了在ZK60镁合金中添加稀土元素的研究存在的问题与不足,并对其发展方向进行了展望.     

稀土元素钇对AM60镁合金铸态和半固态组织的影响

用重力浇注法制得AM60和AM60+1%Y两种镁合金,采用等温热处理法制备半固态组织;分析了Y元素对AM60镁合金铸态组织的影响,研究了等温温度、等温时间及稀土元素Y对AM60镁合金半固态组织演变的作用机理。结果表明:稀土元素Y的添加可以减小AM60的铸态晶粒尺寸;Y与Al结合,形成了高熔点的Al2Y相;而且Y部分置换β-Mg_(17)Al_(12)中的Mg原子,形成(Mg,Y)_(17)Al_(12)相。经过等温处理,AM60和含YAM60镁合金都可以获得良好的半固态组织,AM60+1%Y的等温温度高于AM60镁合金,固相颗粒尺寸约为15μm,远小于AM60镁合金,这主要是由于Al_2Y相在高温下的钉扎和抑制作用。     

稀土元素对汽车座椅支架用AZ60镁合金力学性能的影响

试验研究了稀土元素和热处理工艺对AZ60镁合金材料性能的影响,分析了添加稀土后的AZ60镁合金的力学性能和物相组织。结果表明,AZ60镁合金最佳的稀土添加量为w(Ce)=0.525%、w(La)=0.375%。添加稀土后的AZ60镁合金在420℃固溶处理40 h、210℃时效处理12 h时,其性能最佳,抗拉强度为259.1 N/mm~2,伸长率为13.6%,冲击韧性值为9.5 J/cm~2。最佳物相组成为α-Mg、Mg_(17)Al_(12)、La_3Al_(11)及Ce_3Al_(11)。稀土元素添加可在基体内晶界处起到钉扎作用,使得镁合金材料在断裂过程中裂纹发生偏转,从而形成大量的撕裂棱,最终提高镁合金材料的力学性能。     

复合添加Ce-La对AZ102镁合金镁合金组织及性能的影响

研究了复合添加Ce-La稀土元素对AZ102镁合金组织和性能的影响。结果表明,在α-Mg和β-Mg17Al12相之间出现了Al4(Ce,La)新相,使合金的平均晶粒尺寸减小,并使合金的抗拉强度达到242.54 MPa。     

AZ91镁合金表面铈基稀土转化膜的制备及腐蚀电化学行为

考察了铈盐溶液中的AZ91镁合金电化学行为,包括开路电位,阴、阳极极化行为等,并据此开展了Ce(NO3)3为主盐的稀土盐转化膜研究,在AZ91镁合金表面形成无毒、无污染的铈盐化学转化膜,并研究成膜规律及其耐蚀行为.采用电化学阻抗谱技术优化了处理时间、温度、Ce(NO3)3液浓度和促进剂等因素对膜层结构和膜层耐蚀性能的影响,并获得了最好的成膜条件:处理温度为35℃,时间为30 min,主盐Ce(NO3)3的浓度为0.02 mol/L和促进剂H2O2浓度为4 mL/L.结果表明:采用优化后的工艺能够在AZ91镁合金表面获得宏观黄色致密、微观具有微小裂纹并分层的膜层,表层Ce含量较高.工艺优化制备的稀土化学转化膜能有效提高镁合金的耐蚀性能,有效抑制阴、阳极反应,自腐蚀电位提高250 mV,自腐蚀电流密度降低2个数量级.长期全浸实验结果表明,转化膜能有效提高镁合金的耐腐蚀性能,浸泡60 h后,保护性大大降低.     

电解液中的稀土对AZ91D镁合金微弧氧化陶瓷层的影响

在硅酸盐碱性电解液中加入稀土Ce和Y的络合物[RECit],利用微弧氧化技术在AZ91D镁合金表面制备了陶瓷层,研究了稀土在陶瓷层中的分布,稀土对陶瓷层厚度、孔隙率、表面形貌、陶瓷层相组成以及耐磨和耐蚀性能的影响.研究结果表明,以络合物形式加入到电解液中的稀土可以进入镁合金微弧氧化陶瓷层,能使陶瓷层变得致密,孔隙率减小、MgO与Mg2SiO4的比例提高,表面更加光滑,但使陶瓷层的厚度减小.电解液中稀土元素的加入,对改善镁合金微弧氧化陶瓷层的耐磨及耐蚀性能有明显作用,稀土络合物的适宜加入量约为0.0035 mol/L.     

Influence of rare earth element Ce and La addition on corrosion behavior of AZ91 magnesium alloy

Two types of AZ91 magnesium alloys containing rare earth element Ce or La were fabricated. Hydrogen evolution and electrochemical tests were carried out to evaluate the corrosion behavior of new AZRE (RE = Ce or La) and AZ91 alloys in 3.5% NaCl solutions (pH 6.50). Various corrosion rate tests indicated that addition of RE obviously enhanced corrosion resistance of AZ91 magnesium alloy. The optimal content of RE was 0.92% for Ce and 0.66% for La. Scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and low‐angle X‐ray diffraction (XRD) were used to characterize the effect of RE addition on microstructure and corrosion product film of AZ91 magnesium alloy. The refined β phase and formation of γ phase in AZRE alloy were observed by SEM, which resulted in the improvement of corrosion resistance due to the depression of microgalvanic couples. Moreover, the enhanced protective effectiveness of corrosion products was another reason for the improved corrosion resistance.     

Effect of rare earth element Ce and La on corrosion behavior of AM60 magnesium alloy

New AM60-RE (RE = Ce or La) alloy was prepared and its corrosion behavior was evaluated by hydrogen evolution and electrochemical methods. New γ phase containing higher content of RE and Al elements has been found. The corrosion resistance of AM60 alloy improved with addition of RE, and this improvement could attribute to depression of the micro-galvanic couples, because the fraction of β was decreased, as well as the deposited RE-containing phases were less cathodic. Moreover, RE and Al enrichment in the corrosion product films on the RE-containing alloy surface was also a key factor to the inhibition of further corrosion.     

富Y重稀土对ZM5合金组织和性能影响的研究

以ZM5镁合金为基体材料，以富Y重稀土为添加原料，应用铸造方法制备了稀土镁合金。利用光学金相显微镜（OM）、X衍射分析、拉伸试验和腐蚀试验等方法，考察分析了稀土Y对ZM5合金铸造组织结构、力学性能和腐蚀性能的影响。结果表明，铸态合金中出现了新相Al3La、MgY，它对于减少晶界处第2相的析出、晶粒的细化以及力学性能的提高起着积极作用。同时，稀土的加入明显地改善了合金的腐蚀性能。     

On the corrosion of binary magnesium-rare earth alloys

The corrosion properties of high-pressure die cast (HPDC) magnesium-rare earth (RE) based alloys have been studied. Binary additions of La, Ce and Nd to commercially pure Mg were made up to a nominal 6 wt.%. It was found that the intermetallic phases formed in the eutectic were Mg₁₂La, Mg₁₂Ce and Mg₃Nd, respectively. Results indicated that increasing RE alloying additions systematically increased corrosion rates. This was also described in the context of the electrochemical response of Mg-RE intermetallics - which were independently assessed by the electrochemical microcapillary technique.This study is a discrete effort towards revealing the electrochemical effect of carefully controlled binary alloying additions to magnesium in order to elucidate the microstructure-corrosion relationship more generally for HPDC Mg alloys. Such fundamental information is seen to not only be useful in understanding the corrosion of alloys which presently contain RE additions, but may be exploited in the design of magnesium alloys with more predictable corrosion behaviour. There is a special need to understand this relationship - particularly for magnesium that commonly displays poor corrosion resistance.     

稀土成分对贮氢合金RE（NiCoMnTi）_5电化学性能的影响

系统地研究了稀土组元（ＲＥ＝Ｌａ１－ｘ－ｙ－ｚＣｅｘＮｄｙＰｒｚ）对贮氢合金ＲＥ（ＮｉＣｏＭｎＴｉ）５电化学性能的影响．结果表明，Ｌａ，Ｃｅ，Ｎｄ和Ｐｒ的含量及比例对合金性能有显著影响．为描述稀土组元综合效应，本文引入四组元受约束的成分四边形来表征Ｌａ，Ｃｅ，Ｎｄ和Ｐｒ的成分变化，在此基础上，作出合会的性能对稀土成分的分布图．根据该图，可选择适当的稀土成分，来获得性能优异的贮氢合金电极材料．     

Effect of rare earth metals and the stability of sulfide inclusions on Localized corrosion of low alloy steels

Effect of alloying with rare earth elements RE (La, Pd + Nd, or so called “Mischmetall” containing Ce, Pr, Nd, La and traces of the other RE) on the ability to passivate and susceptibility to chloride breakdown of low alloys steels was investigated. Electron microprobe analysis revealed that the effect of RE depends upon the element and is connected with a modification of the composition and morphology of MnS inclusions present within the steels without RE addition. La seems to be most detrimental. The nonstability of La sulfide inclusions in air results in their spontaneous oxidation and growth into fantastic “flower-like” forms which facilitates the formation of corrosion pits.     

Comparison of corrosion behaviors of AZ31, AZ91, AM60 and ZK60 magnesium alloys

The corrosion behaviours of four kinds of rolled magnesium alloys of AZ31, AZ91, AM60 and ZK60 were studied in 1 mol/L sodium chloride solution. The results of EIS and potentiodynamic polarization show that the corrosion resistance of the four materials is ranked as ZK60＞AM60＞AZ31＞AZ91. The corrosion processes of the four magnesium alloys were also analyzed by SEM and energy dispersive spectroscopy(EDS). The results show that the corrosion patterns of the four alloys are localized corrosion and the galvanic couples formed by the second phase particles and the matrix are the main source of the localized corrosion of magnesium alloys. The corrosion resistance of the different magnesium alloys has direct relationship with the concentration of alloying elements and microstructure of magnesium alloys. The ratio of the β phase in AZ91 is higher than that in AZ31 and the β phase can form micro-galvanic cell with the alloy matrix, as a result, the corrosion resistance of AZ31 will be higher than AZ91. The manganese element in AM60 magnesium alloy can form the second phase particle of AlMnFe, which can reduce the Fe content in magnesium alloy matrix, purifying the microstructure of alloy, as a result, the corrosion resistance of AM60 is improved. However, due to the more noble galvanic couples of AlMnFe and matrix, the microscopic corrosion morphology of AM60 is more localized. The zirconium element in ZK60 magnesium alloy can refine grain, form stable compounds with Fe and Si, and purify the composition of alloy, which results in the good corrosion resistance of ZK60 magnesium alloy.     

Mg-La和Mg-Nd二元合金相稳定性的第一原理研究

La和Nd是镁合金中常用的稀土添加元素,为了帮助理解它们在Mg合金中的强化机制,应用第一原理计算方法,研究了Mg-La和Mg-Nd二元合金的相稳定性.计算结果表明,Mg-La和Mg-Nd合金在Mg₁₂RE和Mg₃RE之间的平衡相分别为Mg₁₇La₂和Mg₄₁Nd₅;La和Nd在Mg中的溶解度大小差别较大,表明者在镁合金中产生强化的机理不同;Mg₃Nd具有比Mg₁₂La更大的弹性模量,因而具有更好的强化效果.     

Corrosion behaviour of AM60 magnesium alloys containing Ce or La under thin electrolyte layers. Part 2: Corrosion product and characterization

The corrosion behaviour of AM60 containing Ce or La (AMRE1) under thin electrolyte layers (TEL) in 3.5 wt.% NaCl solution was investigated. The composition and structure of corrosion product was analyzed by XRD, FTIR, SEM and EDS. The results indicated crystal corrosion products were not affected by TEL and the amorphous ones are Mg(OH)₂ and compounds containing CO₃²⁻ in corroded section and only latter one is present in “unaffected” area. The smart map further confirmed the skeleton structure formed due to RE alloying. Moreover corrosion morphologies of AMRE1 alloys exhibited localized corrosion and pit initiation was inhibited by TEL.     

稀土Ce对Pb-Mg-Al屏蔽材料组织和耐蚀性的影响

采用腐蚀失重试验和动电位极化曲线扫描测试手段,研究Ce元素对Pb-Mg-Al合金在3.5%（质量）NaCl溶液中腐蚀性能的影响。研究结果表明：随着Ce含量的增加,稀土Ce与合金中的Al形成弥散、均匀的金属间化合物Al4Ce,进一步提高了合金的耐蚀性。