Thermal Evolution and Electrical Properties of Rare-Earth Oxide Doped Zirconia

1988 ◽  
Vol 121 ◽  
Author(s):  
B. S. Chiou ◽  
M. Y. Lee ◽  
J. G. Duh
Keyword(s):  
Activation Energy ◽  
Rare Earth ◽  
Ionic Radius ◽  
Thermal Evolution ◽  
Rare Earth Oxide ◽  
Zirconia Ceramics ◽  
Wet Chemical ◽  
Ir Analysis ◽  
Lower Temperature ◽  
The Rare Earth

ABSTRACTSynthesized zirconia ceramics are prepared through the coprecipita-tion process. Application of the wet chemical approach is aimed at the achievement of highly sintered ceramics at lower temperature. The thermal evolution of the synthesized CeO2-ZrO2 powder is investigated with the aid of DTA and TGA measurement. The exothermic peaks on the DTA thermogram are futher identified by the IR analysis. The effect of CeO on the occurrence of the peaks is probed. For other rare-earth oxiae doped ceramics, such as Nd2O3. and Dy2O3. containing zirconia, the bulk and grain boundary resistances are evaluated by the impedance spectroscopy. The dependence of the associated activation energy in the rare-earth oxide doped zirconia is discussed with respect to the variation of the ionic radius of the rare earth constituent.

scholarly journals Recovery of Rare Earth Oxide from Waste NiMH Batteries by Simple Wet Chemical Valorization Process

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1151 ◽  
Author(s):  
Nak-Kyoon Ahn ◽  
Basudev Swain ◽  
Hyun-Woo Shim ◽  
Dae-Weon Kim
Keyword(s):  
Rare Earth ◽  
Active Material ◽  
Rare Earth Oxide ◽  
Recovery Process ◽  
Sulfate Solution ◽  
Reaction Process ◽  
Nickel Metal ◽  
Nickel Metal Hydride ◽  
Wet Chemical ◽  
Almost All

Nickel metal hydride (NiMH) batteries contain a significant amount of rare earth metals (REMs) such as Ce, La, and Nd, which are critical to the supply chain. Recovery of these metals from waste NiMH batteries can be a potential secondary resource for REMs. In our current REM recovery process, REM oxide from waste NiMH batteries was recovered by a simple wet chemical valorization process. The process followed the chemical metallurgy process to recover REM oxides and included the following stages: (1) H2SO4 leaching; (2) selective separation of REM as sulfate salt from Ni/Co sulfate solution; (3) metathesis purification reaction process for the conversion REM sulfate to REM carbonate; and (4) recovery of REM oxide from REM carbonate by heat treatment. Through H2SO4 leaching optimization, almost all the metal from the electrode active material of waste NiMH batteries was leached out. From the filtered leach liquor managing pH (at pH 1.8) with 10 M NaOH, REM was precipitated as hydrated NaREE(SO4)2·H2O, which was then further valorized through the metathesis reaction process. From NaREE(SO4)2·H2O through carbocation, REM was purified as hydrated (REM)2CO3·H2O precipitate. From (REM)2CO3·H2O through calcination at 800 °C, (REM)2O3 could be recovered.

Microstructure and Mechanical Properties of Rare-Earth Doped Si3N4 and Si3N4/SiC Ceramics

2010 ◽  
Vol 65 ◽  
pp. 78-85 ◽  
Author(s):  
Peter Tatarko ◽  
Štefánia Lojanová ◽  
Zdeněk Chlup ◽  
Ján Dusza ◽  
Pavol Šajgalík
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Aspect Ratio ◽  
Ionic Radius ◽  
Earth Element ◽  
Rare Earth Oxide ◽  
Sic Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Significant Difference ◽  
Rare Earth Doped

Microstructure and mechanical properties of Si3N4 and Si3N4 + SiC nanocomposites sintered with rare-earth oxide additives (La2O3, Y2O3, Yb2O3 and Lu2O3) have been investigated. The composites exhibited smaller grain diameter compared to that of monolithic materials. The aspect ratio of β-Si3N4 grains increased with a decreasing ionic radius of rare-earth elements in the Si3N4 monoliths as well as in the Si3N4-SiC nanocomposites. The hardness of both systems increased with a decreasing ionic radius of rare-earth element. The fracture toughness of the materials with coarser microstructure and higher aspect ratio was higher due to the more frequent toughening mechanisms. No significant difference between strength values of monoliths and composites was observed and the strength in the composites was determined mainly by the present processing flaws. Significantly improved creep resistance was observed in the case of composites and for materials with smaller ionic radius of RE3+.

Hrtem Investigation of Effect of Various Rare Earth Oxide Dopants on Epitaxial Zirconia High-k Gate Dielectrics

2002 ◽  
Vol 747 ◽  
Author(s):  
Takanori Kiguchi ◽  
Naoki Wakiya ◽  
Kazuo Shinozaki ◽  
Nobuyasu Mzutani
Keyword(s):  
Rare Earth ◽  
Ionic Radius ◽  
Gate Dielectric ◽  
Gate Dielectrics ◽  
Rare Earth Oxide ◽  
The Other ◽  
High K ◽  
Capacitance Voltage

ABSTRACTThe effects of several rare earth oxide on the capacitance-voltage (C-V) characteristics and the SiO2 interlayer growth of ZrO2 based gate dielectrics were examined. The width of the hysteresis window of La2O3 stabilized ZrO2 (LaSZ) gate dielectric was only 0.2V, on the other hands, that of Sc2O3 stabilized ZrO2 (ScSZ) gate dielectric was 1.4V HRTEM analysis indicated that the growth of SiO2 interlayer of RSZ (R=Sm,Nd,La) gate dielectric was about 1nm, which was less than half of the ScSZ one. These results indicate the advantage of the ZrO2 gate dielectric doped with rare earth oxide composed of larger ionic radius cation.

Nano Crystallite ZrO2, La2O3 and CeO2: Synthesis, Characterization and their Properties

2013 ◽  
Vol 209 ◽  
pp. 212-215
Author(s):  
A.K. Patel ◽  
A.R. Umatt ◽  
B.S. Chakrabarty
Keyword(s):  
Rare Earth ◽  
Surface Area ◽  
Gas Adsorption ◽  
Chemical Properties ◽  
Rare Earth Oxide ◽  
Combustion Method ◽  
Rare Earth Oxides ◽  
Precipitation Method ◽  
Reaction Conditions ◽  
The Rare Earth

It is well known that a minor addition of rare earth oxides can provide a beneficial effect towards various catalytic reactions. Use of rare earth oxide in different applications could improve commercial productivity in an affordable way. Among the rare earth oxides, ZrO2, La2O3 and CeO2 are very interesting due to their various characteristics showing a large range of applications in organic reactions. The changes in the molecular properties of materials at the nano scale level greatly enhance their physical properties as well as chemical properties and activity. Due to the extremely small size of the particles, an increased surface area is provided to the reactant enabling more molecules to react at the same time, thereby speeding up the process. In this work, the enhancement in the catalytic activity of these nano structured rare earth oxides has been studied under different reaction conditions. Nano crystalline ZrO2, La2O3 and CeO2 samples were synthesized using precipitation method and optimum reaction conditions have been established; whereas the corresponding bulk samples were synthesized by combustion method. The identification of phase and crystalline size of synthesized oxides have been done by X-ray diffraction, the band gape of these three oxides in both the forms has been analyzed by UV absorbance and surface area has been determined by gas adsorption analysis (BET). Moreover their different properties and the activity of nano crystallite oxides have also been compared with their bulk counterparts. Even the activity of ZrO2 is also compared with the rare earth oxides La2O3 and CeO2.

Pressure Dependence of the Resistivity of the Rare Earth Oxide Nitrides Eu1−x2+Lnx3+NxO1−x (Ln = Nd, Eu)

1979 ◽  
Vol 93 (1) ◽  
pp. K63-K66 ◽  
Author(s):  
B. Chevalier ◽  
G. Demazeau ◽  
J. Etourneau ◽  
P. Hagenmuller
Keyword(s):  
Rare Earth ◽  
Pressure Dependence ◽  
Rare Earth Oxide ◽  
The Rare Earth

scholarly journals Study of Cracking Mechanism and Wear Resistance in Laser Cladding Coating of Ni-based Alloy

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Zhenglei Yu ◽  
Lunxiang Li ◽  
Deqiang Zhang ◽  
Guangfeng Shi ◽  
Guang Yang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Rare Earth ◽  
Fracture Mechanics ◽  
Composite Coating ◽  
Laser Cladding ◽  
Rare Earth Oxide ◽  
Cracking Mechanism ◽  
Crack Susceptibility ◽  
The Rare Earth

AbstractNickel-based alloy coatings were widely used for the remanufacturing of dies and moulds by laser cladding, but the crack sensitivity would be increase due to the higher strength and hardness, which reduced the wear resistance of Ni-based alloys. In this paper, Ni-based coatings with the addition of a plastic phase (an austenitic stainless net) were prepared using laser cladding technology, and the CeO2 was added in cladding layers. The cracking mechanism, microhardness, microstructure, phase composition, and wear properties were investigated. The relationship between thermal stress and the elastic and plastic fracture had been developed from the standpoint of fracture mechanics and thermal elastic fracture mechanics. The fracture criterion of the nickel-based coating was obtained, and the study has shown that the crack sensitivity could be reduced by decreasing the thermal expansion coefficient Δα. Thus, a new method was proposed, which the stainless steel nets were prefabricated on the substrate. It was found that the number of cracks reduced significantly with the addition of stainless steel net. When the stainless steel net with 14 mesh was added in Ni-based coatings, the average microhardness of nickel composite coating was 565 HV0.2, which was 2.6 times higher than that of the 45 steel substrate. Although the rare earth oxide 4 wt.% CeO2 and stainless steel net were added in the Ni-based coating reducing the microhardness (the average microhardness is 425 HV0.2), the wear resistance of it improved substantially. The wear volume of Ni-based composite coating was 0.56×10−5 mm3·N−1·m−1, which was 85.1% lower than that of 45 steel. The experiment results have shown that the Nickel-based composite coating is equipped with low crack sensitivity and high abrasive resistance with austenitic stainless net and the rare earth oxide 4 wt.% CeO2. This research offers an efficient solution to produce components with low crack susceptibility and high wear-resistance coatings fabricated by laser cladding.

Hrtem Investigation of Effect of Various Rare Earth Oxide Dopants on Epitaxial Zirconia High-K Gate Dielectrics

2002 ◽  
Vol 745 ◽  
Author(s):  
Takanori Kiguchi ◽  
Naoki Wakiya ◽  
Kazuo Shinozaki ◽  
Nobuyasu Mzutani
Keyword(s):  
Rare Earth ◽  
Ionic Radius ◽  
Gate Dielectric ◽  
Gate Dielectrics ◽  
Rare Earth Oxide ◽  
The Other ◽  
High K ◽  
Capacitance Voltage

ABSTRACTThe effects of several rare earth oxide on the capacitance-voltage (C-V) characteristics and the SiO2 interlayer growth of ZrO2 based gate dielectrics were examined. The width of the hysteresis window of La2O3 stabilized ZrO2 (LaSZ) gate dielectric was only 0.2V, on the other hands, that of Sc2O3 stabilized ZrO2 (ScSZ) gate dielectric was 1.4V HRTEM analysis indicated that the growth of SiO2 interlayer of RSZ (R=Sm,Nd,La) gate dielectric was about 1nm, which was less than half of the ScSZ one. These results indicate the advantage of the ZrO2 gate dielectric doped with rare earth oxide composed of larger ionic radius cation.

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