• Title/Summary/Keyword: $Al_2O_3+Y_2O_3$

Search Result 5,795, Processing Time 0.04 seconds

Mechanical Properties of Ni Films and $Ni-Al_2O_3$ Composite Films Fabricated by Electroplating (전기도금법으로 제조한 Ni 박막과 $Ni-Al_2O_3$ 복합박막의 기계적 성질)

  • Jun S. W.;Won H. J.;Lee K. Y.;Lee J. H.;Byun J. Y.;Oh T. S.
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.12 no.3 s.36
    • /
    • pp.259-265
    • /
    • 2005
  • Characteristics of electroplated Ni films and $Ni-Al_2O_3$ composite films, such as yield strength, fracture elongation, and $Al_2O_3$ content, were evaluated as a function of electroplating current density. $Al_2O_3$ content was $11.48\~11.64\;vol\%$ for $Ni-Al_2O_3$ composite films electroplated at $5\~20\;mA/cm^2$, and decreased to $8.41\;vol\%$ at $30\;mA/cm^2$ $Ni-Al_2O_3$ possessed yield strengths higher than those of Ni films. Especially, $Ni-Al_2O_3$ fabricated at $5\;mA/cm^2$ exhibited $50\%$ improved yield strength. Fracture elongations of Ni and $Ni-Al_2O_3$ decreased with increasing the electroplating current density. $Ni-Al_2O_3$ electroplated at $5\;mA/cm^2$ exhibited more uniform dispersion of $Al_2O_3$ and higher yield strength and larger fracture elongation than the composite films processed at other current densities.

  • PDF

Effects of Oxide Additions on Mechanical Properties and Microstructures of AlN Ceramics Prepared from Al-isopropoxide (Al-isopropoxide로부터 제조한 AlN 세라믹스의 기계적 성질과 미세구조에 미치는 산화물 첨가제의 영향)

  • 이홍림;황해진
    • Journal of the Korean Ceramic Society
    • /
    • v.27 no.6
    • /
    • pp.799-807
    • /
    • 1990
  • In this study, effects of oxide additives on mechanical properties and microstructure of A1N and A1N polytype ceramics were investigated. Fine A1N powder was synthesized by nitriding alumiuim hydroxide prepared from Al-isopropoxide, at 1350$^{\circ}C$ for 10h in N2 atmosphere. By adding 3w/o Y2O3, 0.56w/o CaO, and 10w/o SiO2 to AlN powder, AlN and AlN polytype ceramics were prepared by hot-pressing under the pressure of 30 MPa at 1800$^{\circ}C$ for 1h. AlN ceramics with no additives formed considerable amount of AlON phase, while AlN ceramics doped with Y2O3 or CaO decreased AlON phase and formed Y-Al or Ca-Al oxide compound. AlN+10w/o SiO2(+3w/o Y2O3) composition produced AlON and AlN polytype compound having 21R as a major phase. Room temperature flexural strength of AlN ceramics with no additive was 246MPa, and room temperature flexural strength and critical temperature difference by thermal shock(ΔTc) of AlN ceramics dooped with Y2O3 or CaO were 532MPa/340$^{\circ}C$ and 423MPa/300$^{\circ}C$, respectively. Y2O3 and CaO used as sintering agent played roles of densification and oxygen removal of AlN ceramics, and affected grain growth/grain morphologies of AlN ceramics.

  • PDF

Mechanical properties of $Al_2O_3/Mo/MnO_2$ composite ($Al_2O_3/Mo/MnO_2$ 복합재료의 기계적 특성)

  • Park, Hyun;Kim, Kyung-Nam
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.16 no.4
    • /
    • pp.172-179
    • /
    • 2006
  • When $Al_2O_3-MoO_3$ mixture is reduced, $MoO_3$ is only reduced to Mo at $900^{\circ}C$. But a compound between $Al_2O_3$ and Mo is not formed up to $1300^{\circ}C$. In the case of $Al_2O_3-MoO_3-MnO_2$ mixture, an intermediate compound $Mn_2Mo_3O_8$ is firstly formed at $900^{\circ}C$ and changes to $MnAl_2O_4$ at $1100^{\circ}C{\sim}1300^{\circ}C$. $Al_2O_3/Mo/MnO_2$ composite are manufactured by a selective reduction process in which Mo is only reduced in the powder mixture of $Al_2O_3,\;MoO_3\;and\;MnO_2$ oxide. For $Al_2O_3/Mo$ composite, the average grain size was not changed with increasing Mo content because of inhibition of grain growth of $Al_2O_3$ matrix in the presence of Mo particles. Fracture strength increased with increasing Mo content due to phenomenon of grain growth inhibition of $Al_2O_3$ matrix. Hardness decreased because of a lower hardness value of Mo, whereas fracture toughness increased. For $Al_2O_3,\;Mo\;and\;MnO_2$ composite, grain growth was facilitated by MnOB and it showed a lower fracture strength because of grain growth effect with increasing Mo and $MnO_2$ content. Hardness decreased because of the grain growth of matrix and coalesced Mo particles to be located in grain boundary, whereas fracture toughness increased.

Effect of Pt-Sn/Al2O3 catalysts mixed with metal oxides for propane dehydrogenation (프로판 탈수소 반응에 미치는 금속산화물과 혼합된 Pt-Sn/Al2O3 촉매의 영향)

  • Jung, Jae Won;Koh, Hyoung Lim
    • Journal of the Korean Applied Science and Technology
    • /
    • v.33 no.2
    • /
    • pp.401-410
    • /
    • 2016
  • The $Pt-Sn/Al_2O_3$ catalysts mixed with metal oxides for propane dehydrogenation were studied. $Cu-Mn/{\gamma}-Al_2O_3$, $Ni-Mn/{\gamma}-Al_2O_3$, $Cu/{\alpha}-Al_2O_3$ was prepared and mixed with $Pt-Sn/Al_2O_3$ to measure the activity for propane dehydrogenation. As standard sample, $Pt-Sn/Al_2O_3$ catalyst mixed with glassbead was adopted. In the case of catalytic activity test after non-reductive pretreatment of catalyst and metal oxide, $Pt-Sn/Al_2O_3$ mixed with $Cu-Mn/{\gamma}-Al_2O_3$ showed higher conversion of 15% and similar selectivity at $576.5^{\circ}C$, compared to conversion of 8% in standard sample. In the case of catalytic activity test after reductive pretreatment of catalyst and metal oxde, $Cu/{\alpha}-Al_2O_3$ showed higer yield than standard sample. But, increase of yield of most of samples after reductive pretreatment was not significant, so it was found that lattice oxygen of $Cu-Mn/{\gamma}-Al_2O_3$ is effective to propane dehydrogenation.

Characterization of ALD Processed Al2O3/TiO2/Al2O3 Multilayer Films for Encapsulation and Barrier of OLEDs (OLED의 Barrier와 Encapsulation을 위한 원자층 증착 기술로 공정된 Al2O3/TiO2/Al2O3 다층 필름)

  • Lee, Sayah;Song, Yoon Seog;Kim, Hyun;Ryu, Sang Ouk
    • Journal of the Semiconductor & Display Technology
    • /
    • v.16 no.1
    • /
    • pp.1-5
    • /
    • 2017
  • Encapsulation of organic based devices is essential issue due to easy deterioration of organic material by water vapor. Thin layer of encapsulation film is required to preserve transparency yet protecting materials in it. Atomic layer deposition(ALD) is a promising solution because of its low temperature deposition and quality of the deposited film. $Al_2O_3$ or $Al_2O_3/TiO_2/Al_2O_3$ multilayer film has shown excellent environmental protection characteristics despite of thin thicknesses of the films. $Al_2O_3/TiO_2/Al_2O_3$ multilayer and 1.5 dyad layer of $Al_2O_3/polymer/Al_2O_3$ deposited by ALD was measured to have water vapor transmittance rate(WVTR) well below the detection limit($5.0{\times}10^{-5}g/m^2day$) of MOCON Aquatran 2 equipment.

  • PDF

A Study on the Preparation and Sinterability of MgO-Doped $Al_2O_3$ Powders by SprayPyrolysis Method (분무열분해법에 의한 MgO 첨가 $Al_2O_3$ 분체합성 및 소결성에 관한 연구)

  • 박정현;조경식;송규호
    • Journal of the Korean Ceramic Society
    • /
    • v.27 no.4
    • /
    • pp.501-512
    • /
    • 1990
  • Al2O3 and 0.25wt% MgO-doped Al2O3 powders were made from the alcohol solution of Al(NO3)3.9H2O and Mg(NO3)2.6H2O by spray pyrolysis method. Each powder was prepared at 900 and 100$0^{\circ}C$. Powders prepared at 90$0^{\circ}C$ were amorphous phase, but prepared at 100$0^{\circ}C$ wre mainly ${\gamma}$-Al2O3 crystalline form. Particle size of the MgO-doped Al2O3 powders was in the range of 0.2-2${\mu}{\textrm}{m}$, but undooped powders shwoed comparatively wider range of particle size. All the powders prepared at 900 and 100$0^{\circ}C$ were transformed to $\alpha$-Al2O3 crystalline form by calcination at 110$0^{\circ}C$ for 1hr. Each powder was sintered at 1600, 1650 and 1$700^{\circ}C$ for 2hrs. MgO-doped Al2O3 body sintering at 1$650^{\circ}C$ showed 99% of relative density but undooped Al2O3 showed 95% of relative density, even sintered at higher temperature of 1$700^{\circ}C$.

  • PDF

A Study on Phase Transformation and Microstructure Control of $Al_2O_3$ ($Al_2O_3$의 상전이 및 그에 따른 미세구조 제어에 관한 연구)

  • 신상현;오창섭;최성철
    • Journal of the Korean Ceramic Society
    • /
    • v.34 no.6
    • /
    • pp.553-560
    • /
    • 1997
  • A fine $\alpha$-Al2O3 powder was prepared by sol-gel process for membrane application. And it was carried out by adding 1.5wt% $\alpha$-Al2O3 powders(mean size : 87 nm) as seeds to the prepared sols and by controlling the heating schedule (the heating rate and the soaking time) to prevent the microstructural change, which occured during $\theta$-to $\alpha$Al2O3 phase transformation. The seeded $\alpha$-Al2O3 particles acted as the heterogeneous nucleation sites for the $\alpha$-Al2O3 nucleation during the transformation of $\theta$- to $\alpha$-Al2O3 and resulted in increasing the driving force of phase transformation to activate the formation of $\alpha$-Al2O3 phase at 82$0^{\circ}C$. By $\alpha$-Al2O3 seeding and controlling of heating condition the phase transformation of $\theta$- to $\alpha$-Al2O3 was accomplished at low temperature and the grain growth process was depressed. Therefore, the unsupported membrane could be fabricated in $\alpha$-Al2O3 . The average diameter of pores in the fabricated membrane was 7 nm and the porosity was 47%.

  • PDF

A Study on the Effects of $TiO_2$ and $Al(OH)_3$ for ZnO Ceramic Varistor (ZnO Ceramic Varistor에 미치는 $TiO_2$$Al(OH)_3$의 영향)

  • 안영필;김복희
    • Journal of the Korean Ceramic Society
    • /
    • v.19 no.4
    • /
    • pp.287-292
    • /
    • 1982
  • Nonohmic properties of ZnO ceramics with various small amounts of additives were studied in relation to experimental methods, additive contant and sintaring temperature. The kinds of additives used to following chemicals were basic additives ($0.5Bi_2O_3$, $0.3BaCO_3$, $0.5MnCO_3$, $0.5Cr_2O_3$, $0.1KNO_3$), $TiO_2$ and $Al(OH)_3$. Expecially, this study has focused on the effectsof $TiO_2$ and $Al(OH)_3$ in ZnO ceramics with the basic additives. SEM studies indicated that the addition of TiO2 promoted grain growth but retarded grain growth with the addition of $Al(OH)_3$. Also, in the case of calcination of ZnO with $TiO_2$ and ZnO with $Al(OH)_3$ previously, grain size of ZnO with $TiO_2$ was larger and that of ZnO with Al(OH)3 was smaller in comparison to the case with out calcination. From the viewpoint of nonohmic exponent and nonohimic resistance, electrical characteristics of ZnO, $TiO_2$ and the basic additives was more effective than that of ZnO, $Al(OH)_3$ and the basic additives. Nonohmic exponent and nonohmic resistance of ZnO, $TiO_2$ and the basic additives was 11-13 and 40-65 respectively.

  • PDF

Fabrication of a Zirconia Oxygen Sensor Added with $Al_{2}O_{3}$ and Its Characteristics ($Al_{2}O_{3}$가 첨가된 지르코니아 산소센서의 제조 및 그 특성)

  • Sohn, Jeong-Duk;Choi, Sie-Young
    • Journal of Sensor Science and Technology
    • /
    • v.1 no.1
    • /
    • pp.93-100
    • /
    • 1992
  • Sinterability, mechanical and electrical properties of yttria-stabilized zirconia(92 mole% $ZrO_{2}$+8 mole% $Y_{2}O_{3}$) doped with 0.5 mole% $SiO_{2}$ and $0{\sim}2.0 mole%{\;}Al_{2}O_{3}$ were studied as a function of $Al_{2}O_{3}$ addition. Sintered density increased with increasing $Al_{2}O_{3}$ addition up to 0.5 mole % but leveled off with further addition. Victors hardness is proportional to sintered density. The specimen with 0.5 mole% $Al_{2}O_{3}$ and 0.5 mole% $SiO_{2}$ exhibited the maximum electrical conductivity and revealed a maximum electromotive force for a given oxygen partial pressure. Experimental voltage curve of this oxygen sensor take on a sharper, more steplike transition at the stoichiometric A/F ratio than those of other commercial oxygen sensors.

  • PDF