INFLUENCE OF ADDITION OF RARE EARTH ELEMENTS ON THERMAL BARRIER COATINGS MICRO STRUCTURAL EVOLUTION

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4010-4015 ◽  
Author(s):  
XIAOJUAN JI ◽  
QIULI WEI ◽  
CHUNGEN ZHOU ◽  
SHENGKAI GONG ◽  
HUIBIN XU
Keyword(s):  
Rare Earth ◽  
Thermal Diffusivity ◽  
Rare Earth Elements ◽  
Lattice Distortion ◽  
Oscillation Amplitude ◽  
Structural Evolution ◽  
Rare Earth Oxide ◽  
Thermal Barrier ◽  
Barrier Effect ◽  
Lattice Oscillation

Decreasing thermal diffusivity of YSZ can increase the thermal barrier effect. Thermal diffusivity is in direct proportion to lattice oscillation amplitude and frequency. The addition of rare earth oxide into YSZ may induce the lattice distortion, which will result in the change of lattice oscillation frequency. In the present work, combined with the experiment, a theoretical study was proposed to investigate the effect of the rare earth elements on the thermal barrier effect of YSZ using first-principal calculations implemented CASTEP program. It has been found that the addition of the rear earth element can make larger lattice distortion and favorable to reduce the thermal conductivity. The calculation results are in agreement with our experimental results.

scholarly journals Thermophysical properties of BiFeO3/REE multiferroics in a wide temperature range

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060019
Author(s):  
Sidek Khasbulatov ◽  
Suleiman Kallaev ◽  
Haji Gadjiev ◽  
Zairbek Omarov ◽  
Abumuslim Bakmaev ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Rare Earth ◽  
High Temperature ◽  
Thermal Diffusivity ◽  
Rare Earth Elements ◽  
Wide Temperature Range ◽  
Thermophysical Properties ◽  
Multiferroic Bifeo ◽  
Comprehensive Study

The paper presents the results of a comprehensive study of the thermophysical properties (thermal conductivity, thermal diffusivity, heat capacity) of high-temperature multiferroic BiFeO3 modified with rare-earth elements (REEs) (La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu). The regularities of the formation of the mentioned characteristics were established. The assumptions about the nature of the observed phenomena were suggested.

Effect of Re Addition on the Ignition Resistance of Pure Magnesium

2014 ◽  
Vol 788 ◽  
pp. 88-92 ◽  
Author(s):  
Jian Ding ◽  
Zheng Fang ◽  
Lin Qin ◽  
Wei Min Zhao
Keyword(s):  
Rare Earth ◽  
Magnesium Alloy ◽  
Oxide Film ◽  
Rare Earth Elements ◽  
Oxidation Resistance ◽  
Rare Earth Oxide ◽  
Pure Magnesium ◽  
Ignition Point ◽  
The Rare Earth

This paper focus on the effect of rare earth elements addition on the oxidation resistance of pure magnesium. The results show that the ignition points of the Mg-RE alloys vary like “V” along with the increase of the rare earth elements. When the content of Y reaches 10wt%, the ignition point of magnesium alloy is 890K, about 40K higher than the ignition point of pure magnesium. After the addition of rare earth elements, dense oxide film forms on the surface of Mg-RE alloys. The outer oxidation film mainly consists of rare earth oxide.

scholarly journals Valorization of Rare Earth Elements from a Steenstrupine Concentrate Via a Combined Hydrometallurgical and Pyrometallurgical Method

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 248 ◽  
Author(s):  
Yunbo Yun ◽  
Srecko Stopic ◽  
Bernd Friedrich
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Silica Gel ◽  
Rare Earth Oxide ◽  
Research Strategy ◽  
High Tech ◽  
Gel Formation ◽  
Critical Metals ◽  
Main Challenge ◽  
New Research

Due to their unique characteristics, Lanthanides series (15 elements) together with scandium and yttrium are used as critical metals in numerous applications such as energy sources, catalysts, hybrid cars, medical technology, and military industry. The significance of rare earth elements has been continuously increasing because the global demand for producing high-tech devices is continuously rising. The recovery of rare earth oxide from concentrate based on eudialyte and steenstrupine was performed using a hydrometallurgical and pyrometallurgical method. Eudialyte and steenstrupine are a complex Na-Ca-zirconosilicate mineral containing rare earth elements (REEs), Zr, Hf and Nb, thus serving as a potential source of Zr. Because of the presence of silica in eudialyte, the main challenge in its processing is avoiding silica gel formation, which is an unfilterable solid residue. The influence of leaching temperature, time and solid–liquid ratio on leaching efficiency was studied in laboratory conditions. A new research strategy was developed in order to recover rare earth elements using hydrochloric acid, avoiding silica gel formation.

Synchrotron XRD Measurements of Thermal Barrier Coating Configurations With Rare Earth Elements for Phosphor Thermometry

2019 ◽  
Author(s):  
Sandip Haldar ◽  
Peter Warren ◽  
Quentin Fouliard ◽  
David Moreno ◽  
Mary McCay ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Temperature Measurement ◽  
Plane Strain ◽  
Residual Strain ◽  
Strain Distribution ◽  
Temperature Sensing ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Phosphor Thermometry

Abstract The development of temperature sensing Thermal Barrier Coating (TBC) systems by phosphor thermometry has significant potential to achieve accurate non-destructive temperature measurement in the coating. The doping of coatings using rare earth elements is a viable option to enable the temperature measurement by the virtue of their luminescence. While facilitating the temperature sensing, however, the thermo-mechanical and thermo-chemical stability of the coating must be maintained under extreme operating conditions. In this work, TBC configurations including a doped layer placed at the top or the bottom of the top coat have been fabricated via Air Plasma Spray (APS) using Yttria-Stabilized Zirconia (YSZ) that contains Europium (Eu) dopant. The TBC configurations have been characterized using high energy synchrotron X-ray diffraction (XRD) at both room temperature and high temperature. The TBC samples have been subjected to a single cycle thermal load during XRD data collection. The residual strain in the top coats of the TBCs have been quantified using XRD data. Residual strain in the top coat of the regular TBC configuration has been measured to be in the range of −0.8 × 10−4 to −1.0 × 10−4 for out-of-plane strain (e11) and 0.5 × 10−4 to 2.0 × 10−4 for in-plane strain (e22). The doped layer above the top coat was found to most significantly affect the spatial strain distribution across depth in the YSZ layer by increasing the strain magnitudes closer to the bond coat. However, the difference in strain distribution due to doped layers was found to be less than 1.0 × 10−4, which is close to the experimental limit. Thus, the doped layer did not significantly alter the overall residual strain states of the coating.

scholarly journals Effect of Sulfuric Acid Baking and Caustic Digestion on Enhancing the Recovery of Rare Earth Elements from a Refractory Ore

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 532 ◽  
Author(s):  
Rina Kim ◽  
Heechan Cho ◽  
Jinan Jeong ◽  
Jihye Kim ◽  
Sugyeong Lee ◽  
...  
Keyword(s):  
Rare Earth ◽  
Sulfuric Acid ◽  
Rare Earth Elements ◽  
Rare Earth Oxide ◽  
Decomposition Methods ◽  
Major Constituent ◽  
Water Leaching ◽  
Solid Ratio ◽  
Crystallinity Changes ◽  
Leaching Efficiency

To improve the recovery of rare earth elements (REEs) from a refractory ore, this study investigated two different chemical decomposition methods, namely sulfuric acid baking and caustic digestion, with their respective leaching processes. The studied lateritic ore contained goethite (FeOOH) as a major constituent with REEs scattered around and forming submicron grains of phosphate minerals, such as apatite and monazite. Therefore, despite the substantially high content of REEs (3.4% total rare earth oxide), the normal acidic leaching efficiency of REEs reached only 60–70%. By introducing sulfuric acid baking and caustic digestion, the REE-leaching efficiency was significantly improved. After sulfuric acid baking at 2.0 acid/solid ratio and 200 °C for 2 h, the leaching efficiency reached 97–100% in the subsequent water-leaching. When the ore was digested with a solid/liquid ratio of 100 g/L in a 30 wt% NaOH solution at 115 °C and 300 rpm for 3 h, the REE-leaching efficiency of 99–100% was attained at 80 °C using a 3.0 M HCl solution. The correlation between the REE and the Fe-leaching was determined. The improvements in REE-leaching in both methods were mostly attributed to the mineral phase and crystallinity changes of Fe-bearing minerals due to the ore pretreatments. Such findings were also supported by X-ray diffraction and scanning electron microscopy analyses.

scholarly journals Study On The Separation And Extraction Of Rare-Earth Elements From The Phosphor Recovered From End Of Life Fluorescent Lamps

2015 ◽  
Vol 60 (2) ◽  
pp. 1257-1260 ◽  
Author(s):  
D.-W. Shin ◽  
J.G. Kim
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
End Of Life ◽  
Inductively Coupled Plasma ◽  
Rare Earth Oxide ◽  
Precipitation Reaction ◽  
Fluorescent Lamp ◽  
Inductively Coupled ◽  
Fluorescent Lamps ◽  
Heat Treated

Abstract In this study, recovered phosphor from end of life three-wavelength fluorescent lamp was selected for reuse rare earth elements in the phosphor. The effect of a type of acid, concentration, and time was investigated as solubility of rare earth elements. In addition, precipitate heat-treated was investigated as possibility of reusable phosphor. The results showed that the amount of the rare earth elements was different values depending on the type of acid, and it was investigated with concentration of acid and reaction time. After precipitation reaction, the precipitate was sintered in electric furnace in order to reuse rare earth elements as phosphor. It was confirmed that yttrium, europium, oxygen, and carbon through X-ray diffraction and inductively coupled plasma analysis. Following the results, it can assume that rare earth oxide reuse the phosphor as three-wavelength fluorescent lamp.

Tailoring of highly-stable Mn1-x-y(CexLay)O2-δ pseudocapacitor thin-film and rare earth oxide nanospheres through selective purification of rare earth oxides derived from Ni-MH batteries

2022 ◽  
Author(s):  
Samane Maroufi ◽  
Sajjad S. Mofarah ◽  
Rasoul Khayyam Nekouei ◽  
Veena Sahajwalla
Keyword(s):  
Thin Film ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
State Of The Art ◽  
Rare Earth Oxide ◽  
Rare Earth Oxides

Growing utilisation of rare earth elements (REEs) has caused serious shortages in REEs’ supply and shifting state-of-the-art approaches toward sustainable recycling of existing REEs. The present work details a three-stage...

scholarly journals Characterization of rare-earth doped Si3N4/SiC micro/nanocomposites

2010 ◽  
Vol 4 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Peter Tatarko ◽  
Stefánia Lojanová ◽  
Ján Dusza ◽  
Pavol Sajgalík
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Silicon Nitride ◽  
Rare Earth Elements ◽  
Ionic Radius ◽  
Bending Strength ◽  
Rare Earth Oxide ◽  
Positive Influence ◽  
The Matrix

Influence of various rare-earth oxide additives (La2O3, Nd2O3, Sm2O3, Y2O3, Yb2O3 and Lu2O3) on the mechanical properties of hot-pressed silicon nitride and silicon nitride/silicon carbide micro/nano-composites has been investigated. The bimodal character of microstructures was observed in all studied materials where elongated ?-Si3N4 grains were embedded in the matrix of much finer Si3N4 grains. The fracture toughness values increased with decreasing ionic radius of rare-earth elements. The fracture toughness of composites was always lower than that of monoliths due to their finer Si3N4/SiC microstructures. Similarly, the hardness and bending strength values increased with decreasing ionic radius of rare-earth elements either in monoliths or composites. On the other hand, the positive influence of finer microstructure of the composites on strength was not observed due to the present defects in the form of SiC clusters and non-reacted carbon zones. Wear resistance at room temperature also increased with decreasing ionic radius of rare-earth element. Significantly improved creep resistance was observed in case either of composite materials or materials with smaller radius of RE3+. .

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