• 제목/요약/키워드: Mg solid solution

검색결과 207건 처리시간 0.028초

2가 및 6가의 첨가제에 따른 PZT 자기의 유전적 성질에 관한 연구 (A Study on the Dielectric Properties of PZT Ceramics with 2 and 6 Valent Additives)

  • 안영필;이기옥
    • 한국세라믹학회지
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    • 제20권1호
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    • pp.19-24
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    • 1983
  • Dielectrics used as capacitor was studied in the system of $Pb(MgW)_{0.5} O_3-PbTiO_3-PbZrO_3$ Curie tempera-tures of $PbTiO_3 PbZrO_3$ and $Pb[MgW]_{0.5} O_3$ were 49$0^{\circ}C$ 23$0^{\circ}C$ and 39$0^{\circ}C$ respectively. When these materials formed solid solution the more amount of $Pb(MgW)_{0.5}O_3$ was increased the more Curie temperature lowered and dielectric constant increased. Higher dielectric constants were measured in the solid solution of which X-Ray diffraction patterns were changed. Especially Curie temperature and dielectric constant were 85$^{\circ}C$ and 4159 respectively in the composition of 60 $Pb(MgW)_{0.5}O_3-30 PbTiO_3-10PbZrO_3$. Also in this composition ferroeletric material with thermal stability was obtained.

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The Mg Solid Solution far the P-type Activation of GaN Thin Films Grown by Metal-Organic Chemical Vapor Deposition

  • Kim, KeungJoo;Chung, SangJo
    • Transactions on Electrical and Electronic Materials
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    • 제2권4호
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    • pp.24-29
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    • 2001
  • GaN films were grown for various Mg doping concentrations in metal-organic chemical vapor deposition. Below the Mg concentration of 10$^{19}$ ㎤, the thermally annealed sample shows the compensated phase to n-type GaN in Hall measurement. In the MB concentration of 4$\times$10$^{19}$ ㎤ corresponding to the hole carrier concentration of 2.6$\times$1$^{19}$ ㎤ there exists a photoluminescence center of the donor and the acceptor pair transition of the 3.28-eV band. This center is correlated with the defects for a shallow donor of the $V_{Ga}$ and for an acceptor of $Mg_{Ga}$ . The acceptor level shows the binding energy of 0.2-0.25 eV, which was observed by the photon energy of the photocurrent signal of 3.02-3.31 eV. Above the Mg concentration of 4$\times$10$^{19}$ ㎤, both the Mg doping level and Mg concentration were saturated and there Is a photoluminescence center of a deep donor and an acceptor pair transition of the 2.76-eV blue band.

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분말 x선 회절을 통한 $(1-x)Ba(Mg_{1/3}Ta_{2/3})O_3-xLa(Mg_{2/3}Ta_{1/3})O_3$복합페로브스카이트 고용체의 양이온규칙화 및 격자비틀림 분석 (Analysis of cation ordering and lattice distortion of $(1-x)Ba(Mg_{1/3}Ta_{2/3})O_3-xLa(Mg_{2/3}Ta_{1/3})O_3$ complex perovskite solid solution using powder x-ray diffraction)

  • 윤혁준;고경현;홍국선;김환
    • 한국세라믹학회지
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    • 제34권2호
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    • pp.175-180
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    • 1997
  • 새로운 복합페로브스카이트계 고용체 (1-x)Ba(Mg1/3Ta2/3)O3-xLa(Mg2/3Ta1/3)O3(x=0.0-1.0)를 설계하고 조성에 따른 고용체의 결정구조의 변화 및 MPB(Morphotropic Phase Boundary)를 분말 XRD를 이용하여 분석하였다. 초격자회절선의 변화로부터 MBT에 10mol%의 LMT를 치환함에 따라 1:2에서 1:1로의 규칙화타입의 전이가 일어남을 알 수 있었다. 면심입방정구조 영역(0.10.8조성의 경우, 주회절선의 피이크분리 및 새로운 회절선들로부터 격자비틀림의 형태가 단사정임을 알 수 있었다.

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Gadolinium-doped Ceria/Magnesia (CGO/MgO) 복합체 전해질의 전기적 특성 분석 (Electrical Properties of Gadolinium-doped Ceria/Magnesia (CGO/MgO) Composite Electrolytes)

  • 조승환;;김도경
    • 한국재료학회지
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    • 제18권9호
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    • pp.470-474
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    • 2008
  • Composites of gadolinium-doped ceria/magnesia(CGO/MgO) were synthesized and characterized for the electrolytes of intermediate temperature solid oxide fuel cells. XRD and SEM results revealed that composite electrolytes consisted of their own phases after sintering at $1400^{\circ}C$ without noticeable solid solution of Mg into CGO. As the MgO content increased, the total electrical conductivity decreased, which might be attributed to the decrease of grain boundary conductivity, possibly due to the lowering of the continuity of the CGO grains and blocking effects of the insulating MgO phase. The space charge effect may not be a significant factor to affect the electrical conductivity of the CGO/MgO composites.

AZ91-5wt.%Sn 마그네슘 합금의 열처리의 특성 (Heat Treatment of AZ91-5wt.%Sn Magnesium Alloy)

  • 김대환;임수근
    • 한국주조공학회지
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    • 제37권1호
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    • pp.14-20
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    • 2017
  • The microstructure, electrical conductivity and hardness variation of an AZ91-5wt%Sn Mg alloy sample during a solid-solution and aging heat treatment were instigated by optical microscopy, scanning electron microscopy, X-ray diffraction and by Rockwell hardness techniques in this study. The XRD result shows that the main phases in the as-casted alloy are ${\alpha}$-Mg, $Mg_{17}Al_{12}$ and $Mg_2Sn$. From the SEM images of the AZ91-5wt%Sn Mg alloy after the solution treatment, the $Mg_{17}Al_{12}$ phases in the alloy were found to have dissolved into the matrix with an increase in the holding time during the solution treatment, but $Mg_2Sn$ phases were clearly observable. The highest peak hardness of the AZ91-5wt%Sn Mg alloy is 82HRE at an aging temperature of $200^{\circ}C$.

냉.온간포징법을 이용한 차세대 콤프레샤 실린더 블록 개발에 관한 연구 (A Study on the Development for the Future Compressor Cylinder Block Using of Cold & Hot Forging Method)

  • 김순호
    • 한국정보통신학회논문지
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    • 제10권7호
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    • pp.1301-1306
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    • 2006
  • 알루미늄 합금은 자동차부품 및 전자부품산업 개발에 크게 기여하고 있는 소재로서, 제조방법 중 냉?온간 단조 공법에 의해 제조하는 것이 대량 생산되어지는 자동차 및 전자산업부품개발에 있어서 매우 효율적이다. 따라서, 본 연구에서는 차세대 콤프레샤 실린더 블록 개발을 위하여,AI소재 (AI-Mg-Si계합금)를 활용, 냉 -온간 단조법을 이용 하여 개발하고자 한다. 이를 위해, 제조 시편의 미세조직 및 기계적 성질을 조사하였는데,미세조직은 공정형으로 구성되었으며, $Mg_2Si$의 중간상이 석출되었다. 그리고 인장강도는 291.7MPa 로 나타났으며, 그러한 결과를 바탕으 로 차세대 콤프레샤 실린더 블록시제품을 제작하였다.

CMP 폐액의 고액 분리를 위한 최적 응집조건에 관한 연구 (A study on the optimized coagulation for separation of liquid and solid from CMP waste)

  • 홍성호;오석환
    • 청정기술
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    • 제7권1호
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    • pp.27-34
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    • 2001
  • CMP공정에서 발생되는 slurry는 다량의 입자성 물질과 중금속을 함유하고 있다. 이 폐 slurry는 응집성과 침강성에 문제가 있어 처리에 어려움이 있다. 따라서, 본 연구에서는 PACI과 Alum을 이용한 Jar-tester를 통하여 용수 재활용을 위한 최적 응집 조건을 도출하고자 하였다. 고형물 함량이 0.1wt%의 경우 PACI을 응집제로 사용할 때 최적 응집 조건은 pH 4 부터 6에서 투여량은 20~50 mg/L 였으며, 0.5 wt%의 경우 pH 4와 5에서 응집제 투여량은 50~100 mg/L였다.

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현탁된 고형지질나노입자 내로 친수성 약물의 봉입률을 증대시키기 위한 w/o/w 에멀션 가온용융유화법의 평가 (A Hot Melt w/o/w Emulsion Technique Suitable for Improved Loading of Hydrophilic Drugs into Solid Lipid Nanoparticles)

  • 이병무;최성업;이재휘;최영욱
    • Journal of Pharmaceutical Investigation
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    • 제35권1호
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    • pp.33-38
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    • 2005
  • Recently increasing attention has been focused on solid lipid nanoparticles (SLN) as a parenteral drug carrier due to its numerous advantages that can come from both polymeric particle and fat emulsions, together with the possibility of controlled release and increasing drug stability. Lipophilic drugs such as paclitaxel, cyclosporin A, and all-trans retinoic acid have been successfully entrapped in SLN but the incorporation of hydrophilic drugs in SLN is very limited because of their very low affinity to the lipid. Therefore, as a new approach to improve the loading of hydrophilic drugs, a w/o/w emulsion technique has been developed. The primary objective of the current study was to improve the loading efficiency of a model hydrophilic drug, glycine (Log P = -3.44) into SLN. The proposed preparation process is as follows: A heated aqueous phase consisting of 0.1 ml of glycine solution in water (100 mg/ml), and poloxamer 188 (5 mg) were then added to a molten oil phase containing precirol (100 mg) and lecithin (5 mg). This mixture was dispersed by sonicator, leading to a w/o emulsion. A double emulsion (w/o/w) was formed after the addition of 2% poloxamer solution to the above dispersed system. After cooling the double emulsion, solid lipid nanosuspensions were successfully formed. The lipid nanoparticles had the mean particle size of 441.25 nm, and the average zeta potential of -20.98 mV. The drug loading efficiency was measured to be 8.54% and the drug loading amount was measured to be 0.92%. The w/o/w emulsion method showed an increased loading efficiency compared to conventional o/w emulsion method.