• Title/Summary/Keyword: rare earth element

Search Result 190, Processing Time 0.035 seconds

Spectroscopic Studies of Rare-earth Elements in Silicate Glasses (실리카계 유리의 희토류 이온 분광특성 연구)

  • Yoon, Y.Y.;Kim, T.S.;Kil, D.S.;Hwang, Y.;Chung, H.S.
    • Korean Journal of Materials Research
    • /
    • v.8 no.3
    • /
    • pp.219-223
    • /
    • 1998
  • Spectroscopic properties of $Eu^{3+}$, $Sm^{3+}$, $Tb^{3+}$ ions in silicate glasses have been studied. The absorption and emission properties were investigated with the wavelength and rare-earth element concentration. The results showed that the emission spectrum of $Sm^{3+}$ was a transition from $^{5}D_{o}$ excited level to ^{7}F$ ground state and $Sm^{3+}$ was from $4F_{5/2}$ to $^{6}H$ and $Tb^{3+}$ was from $^{5}D_{4}$ to ^{7}F$ The emission intensity was linearly increased with rare-earth element concentrations up to 10wt%.

  • PDF

Plasma etching behavior of RE-Si-Al-O glass (RE: Y, La, Gd)

  • Lee, Jeong-Gi;Hwang, Seong-Jin;Lee, Seong-Min;Kim, Hyeong-Sun
    • Proceedings of the Materials Research Society of Korea Conference
    • /
    • 2010.05a
    • /
    • pp.49.1-49.1
    • /
    • 2010
  • The particle generation during the plasma enhanced process is highly considered as serious problem in the semiconductor manufacturing industry. The material for the plasma processing chamber requires the plasma etching characteristics which are homogeneously etched surface and low plasma etching depth for preventing particulate contamination and high durability. We found that the materials without grain boundaries can prevent the particle generation. Therefore, the amorphous material with the low plasma etching rate may be the best candidate for the plasma processing chamber instead of the polycrystalline materials such as yttria and alumina. Three glasses based on $SiO_2$ and $Al_2O_3$ were prepared with various rare-earth elements (Gd, Y and La) which are same content in the glass. The glasses were plasma etched in the same condition and their plasma etching rate was compared including reference materials such as Si-wafer, quartz, yttria and alumina. The mechanical and thermal properties of the glasses were highly related with cationic field strength (CFS) of the rare-earth elements. We assumed that the plasma etching resistance may highly contributed by the thermal properties of the fluorine byproducts generated during the plasma exposure and it is expected that the Gd containing glass may have the highest plasma etching resistance due to the highest sublimation temperature of $GdF_3$ among three rare-earth elements (Gd, Y and La). However, it is found that the plasma etching results is highly related with the mechanical property of the glasses which indicates the cationic field strength. From the result, we conclude that the glass structure should be analyzed and the plasma etching test should be conducted with different condition in the future to understand the plasma etching behavior of the glasses perfectly.

  • PDF

Formation of Phases and Mechanical Properties of YSZ-Based Thermal Barrier Coating Materials Doped with Rare Earth Oxides (희토류 산화물이 첨가된 YSZ 기반의 열차폐 코팅용 소재의 상 형성 및 기계적 특성)

  • Yong Seok Choi;Gye Won Lee;Sahn Nahm;Yoon suk Oh
    • Journal of Powder Materials
    • /
    • v.30 no.5
    • /
    • pp.402-408
    • /
    • 2023
  • This study focused on improving the phase stability and mechanical properties of yttria-stabilized zirconia (YSZ), commonly utilized in gas turbine engine thermal barrier coatings, by incorporating Gd2O3, Er2O3, and TiO2. The addition of 3-valent rare earth elements to YSZ can reduce thermal conductivity and enhance phase stability while adding the 4-valent element TiO2 can improve phase stability and mechanical properties. Sintered specimens were prepared with hot-press equipment. Phase analysis was conducted with X-ray diffraction (XRD), and mechanical properties were assessed with Vickers hardness equipment. The research results revealed that, except for Z10YGE10T, most compositions predominantly exhibited the t-phase. Increasing the content of 3-valent rare earth oxides resulted in a decrease in the monoclinic phase and an increase in the tetragonal phase. In addition, the t(400) angle decreased while the t(004) angle increased. The addition of 10 mol% of 3-valent rare-earth oxides discarded the t-phase and led to the complete development of the c-phase. Adding 10 mol% TiO2 increased hardness than YSZ.

Solvent Extraction of Rare Earth Elements (La, Ce, Pr, Nd, Sm) from Hydrochloric Acid Solutions using Cyanex 572 (염산용액에서 Cyanex 572에 의한 희토류 원소(La, Ce, Pr, Nd, Sm)의 용매추출)

  • Cho, Yeon-Chul;Kang, Myeong-Sik;Ahn, Jae-Woo;Lee, Jin-Young
    • Resources Recycling
    • /
    • v.25 no.6
    • /
    • pp.50-57
    • /
    • 2016
  • This work was examined the extraction and stripping behavior of rare earths (La, Ce, Pr, Nd, Sm) from the hydrochloric acid solution by Cyanex 572 and compared to the results that of PC88A. Experimental parameters such as equilibrium pH, extractant & strip reagent concentration were observed and extraction percentage, distribution coefficient, stripping percentage and the separation factor of the adjacent element were analyzed. The $pH_{50}$ values was more higher using Cyanex 572 than that of PC88A. As the increase of the extractant concentration, the distribution coefficient of rare earth elements was increased. Stripping percentage of rare earth elementss from the Cyanex 572 was 85% to 95% and PC88A showed 80% to 87%. Separation factor of Ce/La, Ce/Pr, Pr/Nd, Nd/Sm was enhanced about 1.0-5.0 using Cyanex 572 as an extractant in mixture solution.

Separation and Adsorption-Desorption Characteristics of Heavy Rare Earth Elements (Gd, Tb, Dy) using P507 Resin (P507 추출수지를 이용한 중희토류 원소(Gd, Tb, Dy)의 흡탈착 분리특성에 관한 연구)

  • Lee, Sungeun;Kim, Joung Woon;Jeon, Jong Hyuk;Jun, Hong Myeong;Lee, Jin Young;Han, Choon
    • Resources Recycling
    • /
    • v.25 no.4
    • /
    • pp.60-67
    • /
    • 2016
  • This study was conducted to establish the adsorption-desorption mechanism and the optimum condition of chromatographic operation for separations of heavy rare earth elements (Gd, Tb, Dy) using a p507-containing resin. By employing Langmuir and Freundlich isotherm together with pseudo first and second order kinetics, absorption-desorption reaction mechanism was investigated. Langmuir and Freundlich isotherm was applied under assumption that adsorption reaction occurs in form of monolayer, and because the result was identical to the assumption, now we know adsorption of heavy rare earth elements occurs in form of monolayer. Concerning the pseudo first and second order kinetic, the pseudo second order seemed to be more suitable to represent heavy rare earth element adsorption mechanism. By using the extraction chromatography to separate heavy rare earth elements, ${\alpha}^{Tb}_{Gd}=1.24$, and ${\alpha}^{Dy}_{Tb}=1.03$ were confirmed in eluent HCl 0.25 M which indicates almost perfect separations of three elements. Furthermore, as concentrations of eluent became higher, the resolution value decreased and the elution area got shortened.

Distribution and Evaluation of Rare Earth Elements contained in Coal Ashes from Korea Circulating Fluidized Bed Combustion (CFBC) (국내 순환유동층보일러 석탄재의 희토류 분포 특성 및 평가)

  • Kim, Young-Jin;Baek, Chul-Seoung;Seo, Jun-Hyung;Choi, Moon-Kwan;Cho, Kye-Hong;Ahn, Ji-Whan
    • Resources Recycling
    • /
    • v.27 no.6
    • /
    • pp.68-75
    • /
    • 2018
  • The rare earth elements (REE) contents in coal ashes generated from domestic circulating fluidized bed combustion (CFBC) were identified for evaluating the exploitation possibilities for recovering rare earth elements. Total REE contents for all of the samples in this study ranged from 82.2 ~ 311.7 ppm, much lower than the 403.5 ppm given on the average value of world coal ash. As a result of analysis using REE concentration and Outlook coefficient, six types of coal ashes falls in the unpromising area (I). These results suggest that it is difficult to recover rare earth element from coal ashes at this stage. It has been confirmed that to recover rare earth elements in coal ashes, research on the pretreatment and concentration process for critical REE is requirement.

Petrology of the Igneous Rocks in the Goseong area, Gyeongsang Basin II. Trace Element Geochemistry and Rb-Sr Radiometric Age (경상분지 고성지역의 화성암류에 대한 암석학적 연구 II. 미량원소 지구화학과 Rb-Sr 방사성 연대)

  • Jwa, Yong-Joo
    • Economic and Environmental Geology
    • /
    • v.31 no.6
    • /
    • pp.473-483
    • /
    • 1998
  • The igneous rocks in the Goseong area are composed of the volcanic rocks (andesitic lapilli tuff and rhyodacite), Bulgugsa granites (Hornblende-biotite granite and two pyroxene granite) and intrusive andesites. In the variation diagrams of the trace and rare earth element contents and elemental ratios as well as the REE patterns, the three igneous rock types show different variational trends and patterns. The geochemical features represent that the igneous rocks in the area were formed from three different magmatic pulses. Two independently carried out Rb-Sr isotope experiments for the Goseong granites show that the whole rock ages and Sr initial ratios of the granites are $66.4{\pm}6.2Ma$, $0.70517{\pm}22(2{\sigma})$ and $71.3{\pm}6.8Ma$, $0.70506{\pm}18(2{\sigma})$, respectively. These results suggest that the granites magma originated from the lower crustal materials of igneous origin intruded into the area during the late Cretaceous period. Masan hornblende-biotite granite emplaced at the vicinity of the Goseong area is very similar to the Goseong granite in its mineral compositions, major, trace and rare earth element contents and patterns. The intruding age (100 Ma) of the Masan granite is order than that of the Geseong granite, however. The similarity of the geochemical natures but the contrast of the intruding ages between the Masan and Goseong granites possibly indicate that the magma generation from the same source materials occurred at a temporal interval of ca. 30 Ma.

  • PDF