Preparation and Corrosion Resistance of Rare Earth Conversion Coatings on AZ91 Magnesium Alloy

Magnesiumalloysarewidelyusedinweaponin dustry,spacenavigationandhavegoodpotentialof applicationanddevelopmentindailycommunication facilitiesduetotheirpropertiesoflightweightandhighstrength[1].Appliedasstructuralmaterials,mag nesiumalloysmayeasilycrackduet…     

Effect of Rare Earth Cerium on Yield Strength Anisotropy of Al-Li Alloy Sheet and Its Theoretical Prediction

Traceadditionofrareearthinto 2 0 90Al Lialloyisoneofthemeasurestoimproveitslowductilityandtoughness .Al Lialloysheetwithstrongcrystallo graphictexturehasbeenknowntohaveunusuallyhigheryieldstrengthanisotropythanconventionalalu minumalloys[1～3] .However ,ithasnotbeennormallyrecognizedsofarabouttheeffectofceriumonthisanisotropyofAl Lialloy .Someinvestigationsonheat treatableAl Lialloysshowthattheyieldstrengthanisotropyof 2 0 90sheetalloyisdefinitelyassociatedwiththevolumefractionofT1precipita…     

稀土元素在钯基氢净化材料上的应用

根据近年来钯基氢净化材料的研究状况,综述了添加稀土元素对钯基氢净化材料的影响。重点从稀土元素对钯吸氢后形成α相向β相的转变、透氢性能、力学性能以及有害杂质污染的抵抗能力等4个方面进行了阐述。说明添加稀土元素,特别是Y可明显改善钯膜的性能,为低廉、高效获得高纯氢提供了良好的途径。     

Effect of Rare Earth on Microstructure of Vacuum Melting Ni-Based Self-Fluxing Alloy Coatings

The Ni-based self-fluxing alloy coating containing RE was acquired by the technique of vacuum melting on the hypoeutectoid steel (Fe-0.45% C) matrix. By X-ray diffraction, SEM and EDX, the microstructure and phase structure of section of coating and the microstructure near the interface between coating and matrix were investigated, and the effect of RE on microstructure of coating was also discussed. The results show that the microstructure of the NiCrBSi alloy coating is composed of Ni-based solid solution and a lot of massive, globular and needle secondary phases CrB, Ni3B, Cr7C3, Cr23C6 among the solid solution. The metallurgical binding between steel matrix and coating is realized. RE makes needle phase of alloy coating vanish. New phases of NiB and Cr6.5Ni2.5Si are precipitated from alloy coating, and secondary phases of alloy coating are sphericized. Consequently, RE also hinders the diffusion of Ni, Cr and Si atoms from coating to matrix and Fe atoms from matrix to coating, holds back the dilution of Fe for NiCrBSi alloy coating, and assures the chemical composition of the alloy coating.     

Friction and Wear Characteristics of Mg-Al Alloy Containing Rare Earths

The influence of rare earth on the friction and wear characteristics of magnesium alloy AZ91 and AM60 were studied. The results show that the wear resistance properties of rare earth magnesium alloys are better than those of matrix alloy under the testing conditions. The anti-wear behaviour of AZ91 alloy is much better than that of AM60 alloy. In dry sliding pmcess, magnesium alloys undergo a transition from mild wear to severe wear. The addition of rare earths refine the structure of alloys, improve the comprehensive behaviors of magnesium alloys,increase the stability of oxidation films on worn surfaces,enhance the loading ability of rare earth magnesium alloys,and delay the transition from mild wear to sevre wear effectively.     

Effect of Rare Earth on Superplasticity of Zn—5Al Eutectic Alloy

Zｎ Ａｌａｌｌｏｙｉｓｏｎｅｏｆａｌｌｏｙｍａｔｅｒｉａｌｓｗｉｄｅ ｌｙｕｓｅｄｉｎｉｎｄｕｓｔｒｙ .Ｚｎ 5Ａｌｅｕｔｅｃｔｉｃａｌｌｏｙｉｓｎｏｔｏｎｌｙｅｘｔｅｎｓｉｖｅｌｙｕｓｅｄａｓｄｉｅ ｃａｓｔｉｎｇａｌｌｏｙ ,ｈｏｔｐｌａｔｉｎｇａｎｄｓｐｒａｙｉｎｇａｌｌｏｙ ,ｂｕｔｏｂｔａｉｎｓｒｅｃｏｇｎｉｔｉｏｎｉｎｓｕｐｅｒｐｌａｓｔｉｃｓｈａｐｉｎｇａｎｄｓｕｐｅｒ ｐｌａｓｔｉｃｔｈｅｏｒｅｔｉｃａｌｒｅｓｅａｒｃｈｅｓｏｗｉｎｇｔｏｉｔｓｅｘ ｔｒａｏｒｄｉｎａｒｙｓｕｐｅｒｐｌａ…     

稀土元素添加剂在泡沫铝合金制备中的应用

用稀土添加剂制取高强度稀土铝合金，相对抗拉强度σb相：1．07～1．32；延伸率δ：3．0％～7．5％；常压下添加合金增粘剂发泡剂后制得稀土泡沫合金，气孔率η：12．8％～33．5％。     

Effect of Rare Earth on Microstructure of γ-TiAl Intermetallics

The rare earth (RE) elements (Ce, La) were added to binary Ti-47% Al alloys (atomic fraction) by Induction Skull Melting. The element Ce of 1.0 atomic percent was added individually, and La of 0.2 atomic percent was added individually. This article studied the influences of rare earth metal (Ce, La) on microstructure of as-cast TiA1 based alloy by XRD, SEM, EMPA and TEM measurement methodology. The results show that most of rare earth-rich phases (AlCe, Al-La) are uniformly distributed in grain boundary in the shape of discontinuous network, and some particles of rare earthrich phases within the grains are mainly ellipsoids. In addition, rare earth element can obviously refine the grain size and the lamellar thickness of as-cast TiAl based alloy samples. The grain size of Ti-47Al-1.0Ce-0.2La alloy reaches about 30～80μm, and the lameUar thickness of its γ phase and α2 phase are less than 200 and 20nm, respectively.     

Study on Improving Solidification Structure of Rare Earth Al-Si Alloys with Electropulse Acting on Liquid Alloy

Electropulse modification (EPM) process, a new physical field method for improving the solidification structure of metals was introduced.Different from other research, EPM is only acting pulse current on melt under liquid state.The solidification structure of Al-Si alloys, A1-Cu alloys,cast iron and steel can be modified obviously with this method: the solidification structure of ZL101 alloy presented the Na and Sr modification and the mechanical properties were enhanced; a large number of primary silicon appeared in the microstructure of ZL109 alloy; the equiaxed grain zone was expanded and the grains were fined in Al-5.0wt% Cu alloy; the graphitization took place in solidification process of molten cast iron; the grain sizes of solidification structure of T8 steel were reduced significantly and the shape of steel pearlites also changed; the equiaxed grain zone increased to 88% from original untreated 19%, the equiaxed grains were fined and the intercrystalline crack was avoided in concasting billet by continuously treating liquid electrical sheet steel in tundish.Effects of rare earths on casting Al-Si alloys were also summarized.The method of modifying the solidification structure of rare earth Al-Si alloys with EPM in producing the alloys was proposed.     

稀土元素对奥氏体不锈钢焊条熔敷金属组织和性能的影响

在奥氏体不锈钢焊条中，通过在焊条药皮中加入稀土元素。探讨了其对焊条熔敷金属组织和性能的影响。对加稀土前后两种焊条进行了熔敷金属常规拉伸和冲击试验。宏观金相组织分析和冲击断口扫描电镜分析。并对熔敷金属薄片进行了透射电镜分析。结果表明：在奥氏体不锈钢焊条药皮中加入稀土元素。可以细化结晶组织，改变晶界上碳化物的析出形态和分布，并使碳化物的析出数量和颗粒尺寸明显减小，从而净化了奥氏体晶界，提高了其焊条熔敷金属的机械性能。     

Effects of Rare Earth and Alkaline Earth on Spheroidizing of Eutectic Carbides in Low Tungsten White Cast Iron

Tungsten Alloy White Cast Iron(TAWCI) has great brittleness and narrow application scope. The influences of Rare earth element(Ce) and alkaline earth elements ( K, Na) on the microstructures and performances of TAWCI were researched, and the idea estimating spheroidizing effect of carbides using Circular Degree (C. D) were put forward. The result shows that eutectics carbide tums into sphericity from network after modification, and carbide is refined and uniformly distributed and the C. D of eutectic carbide increases. The mechanism of carbide spheroidizing was analyzed. The impact toughness and wear resistance of TAWCI obviously improve with the rise of C. D of carbides.The service life of modified TAWCI roll is 35 % higher than that of high chromium cast iron roll, and its production cost is reduced by 25 %.     

Influence of Rare Earth on Carbide in Weld Metal

Inhardsteelwelds ,thehighcarboncontentisnecessaryandlotsofcarbidesareexpectedtoforminordertoincreasethehardnessandwearresistanceofmaterial.Buttheweldshave poorstrengthandtoughnessowingtotheformationofhighcarbonmartensiteandnetworkcarbides .Ifthecarbidesareturnedinto granularformanddistributedevenly ,thetoughnessofweldmetalcouldbemarkedlyin creased .Forthispurpose ,thehighcarbonNb Ti V Zr REalloysystemwasdesigned .Niobium ,titani um ,vanadiumandzirconiumcouldcombinewithcarbontoformlotsofcarb…     

稀土在铍铜合金中的应用

通过本文的工艺研究及试验，使稀土成功地应用于铍铜合金中，铸锭由于其工艺特点而常出现的气孔，夹杂等缺陷得到了控制，同时大大提高了合金的综合性能，稀土对合金的作用与加入量有直接关系。过多与不及都不好，Cu-RE中间合金在铍铜合金中的最佳加入量为0.1%-0.12%。     

Effects of Rare Earth on Behavior of Precipitation and Properties in Microalloyed Steels

The influence of rare earths on the behavior of precipitation of 14MnNb,X60 and 10Mn V steels was studied by STEM, XRD, ICP and thermal simulation method. The main carbonitride precipitates are Nb(C, N), (Nb, Ti) (C, N) and V(C, N). In austenite RE delays the beginning of precipitation, and decreases the rate of precipitation. In ferrite RE promotes precipitation and increases the amount of equilibrium carbonitride precipitation. RE can make precipitates fine,globular and dispersed in the microalloyed steels. With the increase of the amount of RE in steel, the amount of precipitation increases. The promotion effect is weakened with excessive RE. RE has only little influence on the strength of microalloyed steel, but it can improve impact toughness effectively.     

Study on Preparation and Properties of PVC Film Modified by Rare Earth

The transparent PVC films were prepared by tape casting. In the process of preparation, rare earth nitrate, as a kind of modifier, was added to the solution of PVC and THF. These PVC films were tested after being crosslinked by ultraviolet light. It is found that the mechanical and physical properties of all the PVC films modified by rare earth nitrate are greatly enhanced.     

Effect of Rare Earth Elements on Depositing Rate of Nickel Alloy Brush Plating Coating

The effect of four kinds of rare earth elements on the depositing rate of Ni-based alloy brush plating coatings was investigated. The results indicate that all of the selected rare earth elements increase the depositing rate of Ni-based alloy coatings, and Sm increases the depositing rate most obviously. There is an optimum amount of rare earth addition in the plating solution. With the change of plating voltage to a certain extent, the results reveal no differences. The mechanism of the increase of the depositing rate was analyzed.     

Effect of Rare Earth Elements on Depositing Rate of Nickel Alloy Brush Plating Coatings

ＩｔｈａｓｂｅｅｎｖｅｒｉｆｉｅｄｔｈａｔｔｈｅａｄｄｉｔｉｏｎｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｉｎｔｏｔｈｅｐｌａｔｉｎｇｓｏｌｕｔｉｏｎｃａｎｉｎｃｒｅａｓｅｔｈｅｈａｒｄｎｅｓｓｏｆｔｈｅＮｉ -ｂａｓｅｄｃｏａｔｉｎｇｓａｎｄ ,ｉｎｍｏｓｔｃａｓｅｓ ,ｒｅｌｉｅｖｅｔｈｅｉｒｉｎ ｔｅｒｎａｌｓｔｒｅｓｓ.Ｉｆｔｈｅａｍｏｕｎｔｏｆｒａｒｅｅａｒｔｈａｄｄｉ ｔｉｏｎｉｓｓｕｉｔａｂｌｅ ,ｔｈｅｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｃａｎａｌｓｏｓｔｒｅｎｇｔｈｅｎｔｈｅａｄｈｅｓｉｏｎｏ…     

Role of Rare Earth in Low Sulphur Nb-Ti-Bearing Steel

The effect of rare earth on the microstructures, mechanical properties and inclusions in low sulphur Nb-Ti-bearing steel were investigated. It is shown that the transverse yield point, the traverse tensile strength and elongation of testing steels decrease initially and then rise with increasing content of rare earth. The impact energy values of the testing steels exhibit a contrary trend. Proper amount of rare earth in the steels can improve the anisotropy of impact toughness above -20℃ and it does not affect the type of microstructures which are still composed of ferrites and pearlites, but the pearlite amount increases. On one hand, rare earth cleans the molten steel and reduces the amount of inclusions; on the other hand, rare earth makes the inclusions spheroidizd, refined and dispersed, and thus improves the distribution of inclusions.     

金刚石复合片中稀土硬质合金基片的制备

采用共沉淀法制备含稀土的碳化物粉或含稀土的钴粉，通过真空烧结制成金刚石复合片用稀土硬质合金基片，并进行了性能的测定；研究了真空烧结过程中真空度对合金组织结构的影响。结果证明，稀土元素的加入使合金的平均抗弯强度提高了27％，而对硬度、密度无明显影响；可以通过控制硬质合金真空烧结过程中的真空度来调整合金的组织结构。     

Effects of Heavy Rare Earth Elements on Properties ofAmorphous NiB Alloy Catalyst

Gas-phase hydrogenation of benzene was selected as probe reaction to study the effects of heavy rare earth ele-ments on the catalytic activity and sulfur resistance of amorphous NiB alloy. XRD, DSC, CO chemical adsorption, TPR and TPD were used to characterize the bulk and the surface properties of the alloys, respectively. The results indicate that the addition of a small amount of heavy rare earth (HRE) elements obviously improves the activity, thermal stability and sulfur resistance of amorphous NiB alloy. The HRE can alter H2 adsorption bond strength, increase the surface area of ac-tive nickel and the number of active centers over the surface of NiB alloy and it also can decrease the activation energy of NiB alloy for benzene hydrogenation. There are four kinds of adsorbing sites over the surface of NiB and NiBRE, only three kinds of them have concerned with the reaction.