Examination of Plasma Nitriding Microstructure with Addition of Rare Earths

Medium-carbon alloy steel was plasma nitrided with rare earths I_a, Ce and Nd into the nitriding chamber respectively. The nitriding layer microstructures with and without rare earths were compared using optical microscope, normal SEM and high resolution SEM, as well as TEM. It was found that the extent of the influence on plasma nitriding varies with different contents of rare earth. The effect of plasma nitriding is benefit from adding of Ce or Nd. The formation of hard and brittle phase Fe2-3N can be prevented and the butterfly-like structure can be improved by adding Ce or Nd. However, pure La may prevent the diffusion of nitrogen and the formation of iron nitride, and reduce the depth of diffusion layer.     

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.     

Effects of Rare Earth Oxide on Microstructure of Zinc Varistors

The influence of Pr6O11 on the microstructure of ZnO varistors was researched. The results of experiment indicate that addition of Pr6O11 leads to the change of the formation process of the spinel phase. A lot of pyrochlore phases （ Bi3Zn2Sb3O14 ） produce at about 700℃, and decompose to fine spinel phase （Zn7Sb2O12） when the temperature reaches to 900℃.This type of spinel phase makes ZnO crystal size minor. Also, the phase contained the Pr and different Pr oxides, which makes the whole material crystal size more uniform and compact. The fine structure improves the threshold voltage by about 60%, and modifies nonlinear coefficient of the ZnO material.     

Modification Behavior of Trace Rare Earth on Impurity Phases in Commercial Purity Aluminum

Modifying effect and mechanism of trace rare earth on Fe(Si)-rich impurity phases in commercial purity aluminum were studied with the aids of SEM, EDAX, TEM, etc. It is found that Ce-rich mixed rare earth (RE) is an effective modifying agent, which makes the coarse Fe-rich impurity phases transform into complex compounds of tiny, sphere/short stick form, thus improving mechanical properties of this material; its modifying mechanism is in that RE gathering in front of solid/liquid interface enters into the impurity phases, forming complex (A1FeSiRE) compounds; or is adsorbed in the impurity phases surface, impeding the growth of impurity phases; however, excessive RE will result in the increasing of RE compounds (secondary phases), and plasticity reduction of this material. Therefore, its addition amount should be less than 0.07% (mass fraction).     

Effect of Rare Earth Additives on Chrome-Plating Quality

Electroplatingisoneofthetraditionalprocessesof decorationandsurfaceprotection.Boththeelectroplate principleandprocessparameterscanformacomplete setofsystem.However,therestillexistsixmostseri ousproblemssuchasthepoorcombinationstrengthof electroplatecoatin…     

Effect of Rare Earth Metals on Structure and Properties of Electroless Co-B Alloy Coating

The effect of rare earth metals cerium, lanthanum and yttrium on chemical composition, structure and properties of electroless Co-B alloy coating was studied. By plasma transmitting spectrograph, electron energy spectrometer, X-ray diffractometter, miero-hardometer and vibratory- sample magnetometer the chemical constitution,structure and properties of the alloy coatings were analyzed and inspected. The results show that with a tiny quantity of rare earth metal added into Co-B alloy coating, the content of boron is decreased in the alloy coatings, and the kinds of rare earth metal have enormous effect on the structure and properties of electroless Co-B alloy coating. At the same time electroless Co-B alloy with amorphous structure is transformed to electroless Co-B-RE alloy with microcrystalline or crystalline structure. In this way microhardness of the coatings is increased remarkably. Cerium and lanthanum would also increase the saturated magnetic intensity and decrease coercitive force of the coating. So soft magnetization of the coatings would be improved.     

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.     

Microstructures and Magnetic Properties of As-Cast RE（Dy）-Fe-C（B） Alloys

RE2 Fe14 Ccompoundswithtetragonalcrystalstructureareformedforalmostallrareearthelements(RE ) .Theirmagneticpropertiesareveryclosetothoseofthecorrespondingborides[1～ 5] .Formostofthelightrare earthelements ,La ,Ce ,ProrNd ,itisdifficulttoproducetheRE2 Fe14 Cphase[5～ 7] .Thereasonisthefairlylowtemperature (Tt)ofthesolidstatephasetransformationinthesecompounds .TheydecomposeeasilyintoRE2 Fe17Cxcompoundsathighertemperatures[8,9] .Highcoercivitiescanbeobtainedthroughacontrolledtransformat…     

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…     

Influence of Rare Earth Elements on Microstructure and Mechanical Properties of Mg-Li Alloys

Mg-Li alloy , which is also called superlight al-loy ,has many advantages ,such as lowdensity ,highstiffness-to-weight ratio , superior strength-to-weightratio ,good deformation ability ,good damping ability ,and high energetic particle penetration resistance[1 ,2].These advantages provide promising applicationsintheaerospace , electronic industry , and military field[3].Mg-Li alloys ,such as LA141 , LA191 ,and LAZ933were developed and have been usedfor components insatellites and aircrafts…     

Effect of Yttrium Addition on Microstructures and Room Temperature Tensile Properties of Ti-47Al Alloy

The microstructures and room temperature tensile properties of a series of Ti-47Al-xY （x = 0%, 0.1%, 0.3%, 0.5%, 0.7% and 1.0%（atom fraction）） were investigated systemically. Results show that both the grain size and lamellar spacing decrease remarkably with the increase of Y content. When the content of Y is greater than 0.1%, most of the Y elements accumulate along the grain boundaries and some fine particles are uniformly dispersed within the grains in the form of YAl2 compound because of the low solubility and segregation of Y in TiAl alloys. Grain-boundary seg- regation of Y element is more prominent with the increase of Y addition. Good tensile properties are obtained when Y addition ranges from 0.3 % to 0.5 %. The refinement of grain and lamellar structures and dispersion of YAl2 within the grains contribute to the improvement of tensile properties. On the other hand, for high Y-added alloys （over 0.5% Y）, tensile properties are obviously deteriorated due to brittle cleavage fracture of the coarse YAl2 network.     

Effect of Rare Earth Elements on Anisotropy and Microstructure of AI-Li Alloy 2195 Sheets

For the purpose of decreasing the applied limitation resulting from the anisotropic mechanical property of Al-Li alloy 2195, this study employed a complex heat treatment process, involving the pre-tension, thermo-infiltration of the rare earth element Ce, solution treatment, and artificial aging technology. The results indicate that the infiltration of rare earth element Ce benefits the abatement of anisotropy of Al-Li alloy 2195 sheet, in contrast with that of the normal heat treatment process. The gradient of the Vickers-hardness decreases at least 50% through the thickness, and the tensile strength in the rolling direction also increases significantly. If Ce was infiltrated into the alloy under the optimum pre-deformation, the yield strength （σ0.2） increased by 30 MPa while the tensile strength （σb） enhanced by 25 MPa compared to the rare earth free samples. Meanwhile, the fractography illustrated that the fracture surface of the sample became more desirable.     

Effect of Rare Earth Elements on Quantity Growth of Ctrps

The effects of rare earth on the growth of rice,rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and Development organization(OECD),and the EC50(median growth concenrtation)values were obtained,The inhibition of RE on the growth of rice and rape in red soil and on the growth of soybeanin yellow fouvo-aquic soil is higher with stronger poison effects.Compared with other heavy metals such as Hg,Cd,Pb,As,the poison of RE on crops in weaker.     

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.     

Effect of Rare Earth Elements on Thermal Fatigue Property of Low Chromium Semi-Steel

The effect of rare earth elements on eutectic carbide‘s morphology of low chromium semi-steel in as-cast state and after heat treatment was investigated, and accordingly, the thermal fatigue property of this material was studied. The results show that RE can improve the eutectic carbide‘s morphology, inhibit the formation and propagation of thermal fatigue cracks, therefore, promote the thermal fatigue property, which is more noticeable in case of the RE modification in combination with heat treatment. The optimal thermal fatigue property can be obtained when treated with 0.2% RE modification as well as normalization at 950℃ for 3h.     

Effect of ErCl3 Addition on Microstructures and Properties of AZ91 Magnesium Alloy

Effect of ErCl_3 Addition on Microstructures and Properties of AZ91 Magnesium Alloy     

Modification Effect of P ＋ Sr ＋ Ce Compound on Microstructure and Properties of Cast High Silicon Heat-Resist Aluminum Alloy

Modification Effect of P Sr Ce Compound on Microstructure and Properties of Cast High Silicon Heat-Resist Aluminum Alloy     

Effect of Rare Earths on Microstructure and Properties of Sn2.0Ag0.7CuRE Solder Alloy for Surface Mount Technology

Effect of Rare Earths on Microstructure and Properties of Sn2.0Ag0.7CuRE Solder Alloy for Surface Mount Technology