Papers by Keyword: Erbium

Abstract: The influence of Erbium (Er) addition and thermal treatments on the microstructure and hardness of Al-0.5 wt.%Mg-1.0 wt.%Si alloy has been studied. Chemical composition of the alloys was measured by optical emission spectrometry (OES) and x-ray fluorescence (XRF). Microstructural evolution of as-cast, solution-treated, and aged samples were characterized by scanning electron microscope (SEM). The phase identification and elemental distribution were obtained from energy dispersive spectroscopy (EDS). From the microstructure, it was confirmed that solutionization at 570 ͦ C for 15 hours dissolved the Mg₂Si and Er-rich intermetallics. However, some Fe-rich intermetallics remained after the solution heat treatment. Er addition had a role on the modification of β-AlFeSi and improved the hardness. Er-modified Al-Mg-Si alloy gave a significant improvement in mechanical properties. Therefore, Er is one of the candidate elements that could provide an opportunity for a high-strength Al-Mg-Si alloy.

Abstract: Al-5Zn-0.03In series alloys have been widely studied and used as sacrificial anode materials. Adding rare-earth (RE) element to Al-5Zn-0.03In sacrificial anode is the important way to improve its microstructure and properties. This paper focused on the effect of Er addition on the microstructure and properties of the Al-5Zn-0.03In-xEr alloy. Thermal analysis showed that the presence of Er in the series alloys reduced the solidification ranges and made their liquidus and solidus move to lower temperature. The microstructural analysis and hardness testing reveal that Er existed in the form of precipitation, refined the dendrites of the series alloys and improved the hardness of the series alloys. Investigation of the potentiodynamic polarization and the electrochemical impedance measurements were performed in 3.5 wt. % NaCl solution. The potentiodynamic polarization results indicated that the corrosion potential increased and the corrosion current density reduced with the increase of the Er addition. The Al-5Zn-0.03In alloy shows higher corrosion resistance with the increase of Er content. The EIS electrochemical impedance results showed that Al-5Zn-0.03In anode presented relatively uniform dissolution due to the refined microstructure by the addition of Er.

Abstract: The spectroscopic performance of Er³⁺ doped glass at 0.55 mm emission contain different nanoparticles NPs have been comparatively evaluated. Glass containing 1.0 mol % of Er³⁺ doped with different NPs (Ag, Co and Fe ) have been prepared using melt quenching technique. X-ray diffraction analysis reveals the all the prepared samples are amorphous. The UV-Vis absorption spectra of all glasses show several prominent peaks at 525 nm, 660 nm, 801nm, 982 nm and 959 nm due to transition from ground state ⁴I_15/2 to different excited of ²H_11/2, ⁴F_9/2, ⁴I_9/2, ⁴I_11/2, and ⁴I1_3/2. The emission of Er³⁺ at 0.55 mm for glass contain Ag NP shows significant enhancement about 3 folds up to 0.6 mol%. On the other hand, the emission of Er³⁺ at 0.55 mm for glass containing Fe NPs and Co NPs intensely quench probably due to the energy-transfer from Er³⁺ ion to NPs and magnetic contributions.

Abstract: The effect of rare earth metal erbium (Er) modification on the microstructure and mechanical properties of aluminium alloys (A380) were investigated using Optical Microscope (OM), Scanning Electronic Microscope (SEM) attached with Electron Dispersive Scanning (EDS), Vicker’s hardness test and Ultimate Tensile Test (UTS). The results show that the addition of Er reduces the size of the silicon particle and improve mechanical properties of the aluminium alloy. In addition, by adding 0.1 wt. % of Er, the mean area (μm²) and aspect ratio value decreased. The coarse plate like existed in the unmodified alloy transformed into fine particle and short rod. The mechanical properties were investigated by using tensile test and Vicker’s hardness test. The ultimate tensile strength test shows that the tensile and the elongation increased 1.32 % and 9.1 % with 0.1 wt. % Er content of the aluminium alloys, respectively. The hardness improved from the addition of 0.1% Er aluminium A380 alloy.

Abstract: A novel Al-Er master alloy has been prepared through in situ metallothermic reactions of NaErF₄ and aluminium melts. The compound NaErF₄ is formed as a result of the interaction of NaF and ErF₃ in the melt medium KCl. The metallothermic reactions produce erbium, which through low solubility in molten aluminium and forms intermetallic compound Al₃Er. The microstructures of the Al-Er master alloy with different contents of the alloying metal has been investigated. The results showed that the Al-Er master alloy mainly consisted of phases of α-Al and Al₃Er, that confirmed by the results of X-ray diffraction. Backscattered electron imaging of the Al-Er master alloy under a scanning electron microscope (SEM) revealed the presence of phase Al₃Er, which crystallized in the eutectic composition [Al+Al₃Er]. The observed microstructure is explained according to the eutectic reaction in an Al-Er phase diagram. The preparation of Al-Er master alloy by the metallothermic reduction method will allow to reduce energy consumption for master alloy production and to reduce the cost of aluminium alloys alloyed with Er through the novel master alloy.

Abstract: The 6061 aluminum alloys with different content of erbium were prepared. The erbium content was optimized by measurement of grain refining effects and tensile strength. After solid solution treatment of the alloy with optimized erbium content at 505 °C ~ 595 °C for 4 h. and then ageing at –160 °C ~ 200 °C for 3 h., the grain size decreased with the content of erbium, achieving the most effective grain size refinement at the erbium content of 0.15wt.%. The tensile strength of as-cast alloy could reach up to 243 MPa at the erbium content of 0.15%. -Combined with the microstructures and mechanical properties, the erbium content of 0.15% was the optimized content, and heat treatments of ageing at 180 °C for 3 h. followed by solid solution at 565 °C for 4 h were suggested.

Abstract: Er³⁺-doped ZnO – BaO – TeO₂ glasses with the formula (80-x)TeO₂–15ZnO–5BaO–xEr₂O₃ were fabricated using melt quenching technique. The 5 glass samples with different concentrations of Er₂O₃ were prepared under atmospheric pressure. The samples were investigated on their properties: density, molar volume, absorption spectra and photoluminescence. Density was increased with an increase in Er³⁺ content. The molar volume trend is in the opposite way to that of the density. The absorption bands are assigned as absorptions from the ⁴I_15/2 ground state to the ⁴F_7/2, ²H_11/2, ⁴S_3/2, ⁴F_9/2, ⁴I_9/2, ⁴I_11/2 and ⁴I_13/2 levels. All absorption bands are increase with increasing content of Er³⁺. The photoluminescence spectra were measured with 980 nm light pumped by flash lamp. The spectra trends to increase with increasing concentration of the dopant.

Abstract: The role played by transition elements and rare earths, added in small quantities (fractions of unity in weight percent) was proved by several authors to be beneficial for the age-hardening response and for the microstructural stability at high temperature of Al-based alloys. The paper illustrates the results of an experimental investigation on the effects of erbium (Er) additions on the microstructural features, microstructural stability and mechanical properties of an Al-7Si-0.4Mg alloy of wide industrial use. The effects are multifold: in the cast microstructure, a silicon (Si) eutectic modification was observed with the formation of several Er-containing intermetallic phases. After solution treatment and aging, an increase in peak hardness and an enhanced microstructural stability were obtained. In this preliminary study, the beneficial effects of Er additions were confirmed.

Abstract: Powder samples of (Ca,Sr)TiO₃:Er were prepared by a solid-state reaction method. Photoluminescence due to f-f transitions of Er³⁺ was not induced by band-gap excitation of (Ca,Sr)TiO₃ but by f-f transitions of Er³⁺. An electroluminescent device in which thin films of Ca_0.6Sr_0.4TiO₃:Er and SnO₂:Sb are stacked alternately was prepared by sol-gel and spin-coating methods. Very weak electroluminescence due to f-f transition of Er³⁺ was observed in the device.

Abstract: Er³⁺ ions doped bismuth borophosphate glasses are prepared in different concentration by the conventional melting-quenching method at 1200 °C. Physical properties, absorption and luminescence spectra under visible excitation are investigated. The results showed that density of glasses tended to decrease with increasing the concentration of Er₂O₃. While, the molar volume of glasses tended to increase with increasing the concentration of Er₂O₃. The optical absorption spectra were clearly observed in ultraviolet (UV), visible light (VIS) and near infrared (NIR) region. Visible emission spectra have been recorded by exciting the glass samples at 326 nm. The strongest intensity was the green emission at 521 nm. The luminescence intensity was found to increase with Er₂O₃ content up to 0.8 mol% and it was decreased for higher Er₂O₃ contents due to concentration quenching effect.