Papers by Keyword: Rare Earth (RE)

Abstract: The effect of rare earth element on structure and mechanical properties of the 430 ferrite stainless steel was studied by metallographic examination, scanning electron microscope (SEM), tensile test and impact test. The results show that the proper amount of RE can refine microstructure of 430 ferrite stainless steel. The fracture mode of 430 ferrite stainless steel is typical dimple fracture. 430 ferrite stainless steel containing 0.056% RE can improve its impact toughness and the high temperature strength, and the transverse impact toughness increases 37.2% at 253K respectively comparing with that of 430 ferrite stainless steel without RE. And at 1273K, the high temperature strength increases by 38.3% than that of 430 ferrite stainless steel without RE.

Abstract: The addition of alloy elements can improve the properties of aluminum alloy markedly. In the paper, three kinds of aluminum alloys were studied. By using SEM, EBSD and some other devices, the affects of microalloying elements on high strength and high conductivity aluminum alloy structure and properties were investigated.

Abstract: A series of single-phase Sr₅(PO₄)₃F: Eu²⁺, Tb³⁺, Na⁺ phosphors have been synthesized by high temperature solid-state reaction. The photoluminescence excitation and emission spectra, concentration effect and energy transfer from Eu²⁺ to Tb³⁺ are investigated in detail. The work shows that there is an effective energy transfer from Eu²⁺ to Tb³⁺, where Eu²⁺ reveals an intense excitation band from 280 nm to 400 nm, matching well with the emission of n-UV chips, and Tb³⁺ emits an intense green emitting light.

Abstract: The upconversion (UC) luminescence properties of phosphor Tm³⁺/Yb³⁺ co-doped Gd₂Mo₃O₉were investigated in detail. Tm³⁺/Yb³⁺ co-doped Gd₂Mo₃O₉was prepared by solid-state reaction method using Na₂CO₃ as flux and characterized by powder X-ray diffractometry. Under 980nm excitation, Tm³⁺/Yb³⁺ co-doped Gd₂Mo₃O₉has exhibited a weak red emission near 651nm and strong blue emission at 476nm. Tm³⁺/Yb³⁺ co-doped Gd₂Mo₃O₉phosphor has been considered as a better candidate in solid-state lighting applications.

Abstract: The electrochemical behavior of a new magnesium alloy (AZ61) containing rare earth elements-cerium (Mg-Al-Zn-Mn-Ce alloys) was investigated in 3% NaCl electrolyte using electrochemical methods such as linear sweep voltammetry, Tafel curves and electrochemical impedance spectroscopy. Scanning electron microscopy was used to characterize the surface morphologies of magnesium and its alloys. The results shows that compared with that of the most commonly used Mg alloy–AZ61, the cerium containing magnesium alloy exhibited higher electrochemical activity, and higher corrosion resistance. The electrochemical activity of Mg-Al-Zn-Mn-Ce was higher than that of Mg and Mg-Al-Zn-Mn-Ce alloys in 3% NaCl. The corrosion resistive order decreased in the following sequence: Mg-Al-Zn-Mn-Ce > Mg-Al-Zn-Mn > Mg. The electrolytes favored anodic magnesium oxidation, but the alloying element of Ce facilitated the formation of dense passive films on alloy surfaces.

Abstract: A new Mg₆₅Cu₁₈Ni₆Gd₁₁ bulk metallic glass (BMG) with high level of Ni content, exhibiting glass-forming ability (GFA) of 6 mm, was fabricated by copper mold casting. The compressive strength and plasticity of the Mg₆₅Cu₁₈Ni₆Gd₁₁ BMG were 938 MPa and 0.14%, respectively. The composition design of the Mg₆₅Cu₁₈Ni₆Gd₁₁ BMG with enhanced GFA had succeeded simply using Gd substituting Y in the Mg₆₅Cu₁₈Ni₆Y₁₁ BMG, which was a result of a comparison on the GFA between the Mg-TM-Gd and Mg-TM-Y BMGs (TM: transition metals). Compared to the Mg-TM-Y BMGs, the Mg-TM-Gd BMGs exhibited improved GFA, which was demonstrated to be mainly attributed to the more negative amorphous formation enthalpy resulting from Gd substituting Y. The effects of rare earth (RE) elements on the GFA of Mg-TM-RE were discussed. This work may suggest an easy way for developing new Mg-based BMGs with improved GFA by rare earth (RE) design.

Abstract: The luminescent material, composed of rare-earth-doped alkaline earth aluminate, has been paid wide attention because of its chemical stability, usability and non-radioactive. In this study, the luminous material SrAl₂O₄:Eu²⁺,Dy³⁺ was prepared by a microwave method. The effect of microwave parameters on the performance of the luminous powder was investigated. The excitation and emission spectrum of the luminous material were measured by fluorospectrophotometer. The phase composition of the powder was analyzed by XRD. The results show that the luminous powder can be synthesized only when the microwave power is higher than the med-high fire (640W). The sample has the best luminous property when the molar ratio of Sr (NO₃)₂:Al (NO₃)₃·9H₂O:H₃BO₃:Eu (NO₃)₃·6H₂O:Dy (NO₃)₃·6H₂O is about 1:2:0.5:0.04:0.08, and it is processed by high power for 20min in microwave oven.

Abstract: The Pr₂O₃ doped SnO₂ dense ceramic was prepared by co-precipitation method and further sintering. Through the micrograph of the cross-sectional microstructure of the electrodes, the sintering process was analyzed and discussed. Results showed that the solid phase sintering was exhibited at the early stage; when sintering was kept going on, the instant liquid phase could be emerged due to the rich dopants in the grain boundary. Finally, there would be much secondary phase existe as the concentration of dopants reached to a certain value.

Abstract: The effect of RE on modifying inclusions of 430 ferrite stainless steel was studied by metallographic examination, SEM and electron spectroscopy. Thermodynamic calculation was used to analyze the formation of RE inclusions in 430 ferrite stainless steel. The result shows that sulfide and other irregular inclusions are modified to round or oval-shaped RE2O2S and RES.

Abstract: The effect of rare earth element on structure and mechanical properties of 2205 duplex stainless steel were studied by metallographic examination, scanning electron microscope (SEM), tensile test and impact test. The results show that the proper amount of rare earth can refine microstructure of 2205 duplex stainless steel. Fracture is changed from cleavage to ductile fracture by adding RE to 2205 duplex stainless steel. 2205 duplex stainless steel containing 0.05% RE can improve its impact toughness, and the transverse impact toughness is increased 15.56% at -20°C respectively comparing with that of 2205 duplex stainless steel without RE.