전고체전지용 붕산염 유리 세라믹 고체 전해질의 조성비에 따른 소결 특성 연구

이정민 ( Jeong Min Lee ),정동석 ( Dong Seok Cheong ),강성현 ( Sung Hyun Kang ),( Tirtha Raj Acharya ),최은하 ( Eun Ha Choi ),신원호 ( Weon Ho Shin ) 한국전기전자재료학회 2024 전기전자재료학회논문지 Vol.37 No.4

The expansion of lithium-ion battery usage beyond portable electronic devices to electric vehicles and energy storage systems is driven by their high energy density and favorable cycle characteristics. Enhancing the stability and performance of these batteries involves exploring solid electrolytes as alternatives to liquid ones. While sulfide-based solid electrolytes have received significant attention for commercialization, research on amorphous-phase glass solid electrolytes in oxide-based systems remains limited. Here, we investigate the glass transition temperatures and sintering behaviors by changing the molecular ratio of Li₂O/B₂O₃ in borate glass comprising Li₂O-B₂O₃-Al₂O₃ system. The glass transition temperature is decreasing as increasing the amount of Li₂O. When we sintered at 450℃, just above the glass transition temperature, the samples did not consolidate well, while the proper sintered samples could be obtained under the higher temperature. We successfully obtained the borate glass ceramics phases by melt-quenching method, and the sintering characteristics are investigated. Future studies could explore optimizing ion conductivity through refining processing conditions, adjusting the glass former-to-modifier ratio, and incorporating additional Li salt to enhance the ionic conductivity.

치과용 지르코니아 도재의 Li₂O 첨가에 따른 열팽창계수 변화

한석윤,Yoon, Han-Sok 대한치과기공학회 2009 대한치과기공학회지 Vol.31 No.4

Zirconia($ZrO_2$) has attracted much attention in science and technology because of its high refractive index, high melting temperature, hardness, low thermal conductivity and corrosion barrier properties. And it is widely used as the dental restoration material because of its esthetic appearance. In this research, we analyzed the particle size and composition of the imported dental porcelain for zirconia. And the glass frit was produced. To decrease the glass transition temperature and softening temperature of the glass frit, $Li_2O$ was added into it and the effect of $Li_2O$ on the firing temperature was researched. Then the glass which contains leucite crystal with a high coefficient of thermal expansion(CTE) was manufactured and it was mixed with the glass frit to control the CTE. The phase composition were analyzed using the X-ray diffraction. The morphologies of the samples were observed by the scanning electron microscope. The 4wt% $Li_2O$-added glass frit has the optimal glass transition temperature and softening temperature. And 6 wt% leucite crystal was mixed with the glass frit to control the CTE. From the experimental results of crystallization, the crystal phase was found only leucite crystal.

The Thermal Stability Evaluation of Silver Tellurite Glass for Radioactive Iodine Immobilization

Seong-Sik Shin,Byeong Gwan Lee,Hyeon Jin Eom,Ga Yeong Kim,Hyun Woo Kang,Jung-Hoon Choi,Ki Rak Lee,Hwan-Seo Park 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

Uranium-235, used for nuclear power generation, has brought radioactive waste. It could be released into the environment during reprocessing or recycling of the spent nuclear fuel. Among the radioactive waste nuclides, I-129 occurs problems due to its long half-life (1.57×107 y) with high mobility in the environment. Therefore, it should be captured and immobilized into a geological disposal system through a stable waste form. One of the methods to capture iodine in the off-gas treatment process is to use silver loaded zeolite filter. It converts radioactive iodine into AgI, one of the most stable iodine forms in the solid state. However, it is difficult to directly dispose of AgI itself in an underground repository because of its aqueous dissolution under reducing condition with Fe2+. It must be immobilized in the matrix materials to prevent release of iodine as a result of chemical reaction. Among the matrix glasses, silver tellurite glass has been proposed. In this study, additives including Al, Bi, Pb, V, Mo, and W were added into the silver tellurite glass. The thermal properties of each matrix for radioactive iodine immobilization were evaluated. The glasses were prepared by the melt-quenching method at 800°C for 1 h. Differential scanning calorimetry (DSC) was performed to evaluate the thermal properties of the glass samples. From the study, the glass transition temperature (Tg) was increased by adding additives such as V2O5, MoO3, or WO3 in the silver tellurite glass. The relative electro-static field (REF) values of V2O5, MoO3, and WO3 are about three times higher than that of the glass network former, TeO2. It could provide sufficient electro-static field (EF) to the TeO2 interacting with the non-bridging oxygen forming Te-O-M (M = V, Mo, W) links. Therefore, the addition of V2O5, MoO3, or WO3 reinforced the glass network cohesion to increase the Tg of the glass. The addition of MoO3or WO3 in the silver tellurite glass increased Tg and crystallization temperature (Tc) with remaining the glass stability.

적외 광투과 Chalcogenide계 유리의 제조 및 특성

송순모,최세영 한국세라믹학회 1995 한국세라믹학회지 Vol.32 No.12

Chalcogenide glasses having IR (8~12${\mu}{\textrm}{m}$) transmittance were prepared and their densities, thermal and mechanical properties, IR-transmittances and chemical durabilities were determined. Glass transition temperatures (Tg) of Ge-As-Se, Ge-As-Se-Te and Ge-SE-Te system glasses were in the range of 280~3$65^{\circ}C$, 210~236$^{\circ}C$ and 210~26$0^{\circ}C$, respectively. Crystallization temperature (Tc) of Ge-Se-Te system glass was in the range of 305~40$0^{\circ}C$. Their thermal expansion coefficients($\alpha$) were in the range of 11.7~15.2$\times$10-6/K, 15.4~16.0$\times$10-6/K and 17.4~27.8$\times$10-6/K, respectively. Their MOR, hardness and fracture toughness were in the range of 15.2~18.6MPa, 36.1~58.2Kg/$\textrm{mm}^2$, 1.0~1.3 MPa.mm1/2, 18.9~24.9 MPa, 40.9~65.1Kg/$\textrm{mm}^2$, 1.3~1.5 MPa.mm1/2, and 24.1~30.8 MPa, 40.9~86.0Kg/$\textrm{mm}^2$, 1.4~1.8 MPa.mm1/2, respectively. IR transmittance of Ge-Se-Te system glass was about 60%. Ge-O extrinsic absorption peaks at 8, 12 ${\mu}{\textrm}{m}$ were significantly eliminated by the addition of Mg. Chemical durabilities in deionizied water of Ge-Se-Te system glass were good and IR-transmittances decreased with leaching time and temperature.

Effects of temperature on dynamic compressive properties of Zr-based amorphous alloy and composite

Lee, D.G.,Kim, Y.G.,Hwang, B.,Lee, S.,Lee, Y.T. Elsevier Sequoia 2008 Materials science & engineering. properties, micro Vol.472 No.1

This study investigates the high-temperature dynamic compressive deformation behavior of Zr-based amorphous alloy and amorphous matrix composite containing ductile β crystalline phases. Dynamic compressive tests were conducted in the temperature range from room temperature to 380<SUP>o</SUP>C using a compressive Kolsky bar, and then the test data were analyzed in relation to microstructure and fracture mode. Dynamic compressive test results indicated that both the maximum compressive stress and the total strain of the amorphous alloy and composite decreased with the increasing test temperature because shear bands could propagate rapidly as the adiabatic heating effect was added at high temperatures. Above the glass transition temperature, total strain decreased more abruptly than that measured between the room temperature and 300<SUP>o</SUP>C according to the crystallization of amorphous phases. The maximum compressive stress and the total strain of the amorphous composite were higher than those of the amorphous alloy in the overall test temperature range because β phases played a role in forming multiple shear bands. These findings suggested that applying the evaluation criteria for mechanical properties measured under room temperature quasi-static loading could cause risks when the Zr-based amorphous alloy and composite were used at high temperatures under dynamic loading conditions.

EAF dust가 함유된 붕규산염계 결정화 유리의 미세구조 분석

안영수,강승구,김유택,이기강,김정환,Ahn, Y.S.,Kang, S.G.,Kim, Y.T.,Lee, G.K.,Kim, J.H. 한국결정성장학회 2006 韓國結晶成長學會誌 Vol.16 No.2

붕규산염계 유리 프리트에 중금속이 다량 함유된 전기로 EAF dust(전기로 제강분진, 이하 더스트)를 $10{\sim}80wt%$ 범위로 첨가한 후 용융하여 유리 시편을 얻었다. 제조된 유리의 DTA분석 결과로부터 유리전이온도, $T_g$가 $550^{\circ}C$ 부근임을 확인하였고 이로부터 결정화에 필요한 열처리 조건을 $700^{\circ}C$/10 hr으로 정하였다. 더스트 첨가량이 70wt% 이상인 유리시편은 XRD 분석 결과 spinel 결정 피크만이 나타났으며, 결정화 시편의 경우, 더스트 첨가량이 40wt% 이상부터 spinel 결정이, 80wt% 부터는 spinet과 willemite 피크가 함께 검출되었다. XRD 분석으로는 결정상이 검출되지 않았던 조성의 유리시편에서도 aspect ratio=$0.7{\sim}1.0$인 수십 nm 크기의 결정상 존재가 SEM으로 확인되었고 결정화 시편에서도 더스트 함량이 l0wt%부터 결정상이 관찰되었다. 결정화 시편에서 관찰된 결정상은 그 형태와 분포가 첨가량에 따라 다양하고 비균일 하였으나 더스트 첨가량이 70wt%인 시편에서는 aspect ratio가 1에 가까운 6면체 형상을 나타내었다. Glassy specimen was obtained by melting and quenching a borosilicate glass frit miked with $10{\sim}80wt%$ EAF dust. The glass transition temperature, $T_g$ of glassy specimen was measured around $550^{\circ}C$ from the DTA curve and the eat treatment condition to crystallize a glassy specimen was selected as $700^{\circ}C$/1 hr. The spinel crystal peaks were found in XRD analysis for the glass containing dust > 70 wt%. For the glass-ceramics, however, the spinel peaks in a specimen containing dust > 40 wt%, and the spinel and willemite peaks in dust > 80 wt%. The crystals of several tens of nanometer with aspect ratio of $0.7{\sim}1.0$ were observed at a glassy specimen containing dust > 40 wt% by SEM which was not found by XRD analysis. For the glass-ceramics, the crystals were found in a specimen containing dust of even 10 wt% by SEM. The feature and distribution of crystals observed through the specimen for a glass-ceramics were diverse and not uniform. The crystals found in the glass-ceramics containing 70 wt% dust were hexahedral with an aspect ratio of around unity.

논문 : 기계적 성질 ; 비정질 Al-Ni-Y합금의 생성과 고온물성

김영환 ( Yeong Hwan Kim ),김윤호 ( Yun Ho Kim ),김진한 ( Jin Han Kim ) 대한금속재료학회 ( 구 대한금속학회 ) 1998 대한금속·재료학회지 Vol.36 No.7

Formation range of the amorphous phase in melt-spun Al-Ni-Y alloy system was investigated. The amorphous single phase was obtained when the content of solute(Ni+Y) is more than 10at%. Then, the addition of Y atom was more effective than that of Ni atom. The crystallization of amorphous Al90-xNi10Yx, (x=2, 4, 6 at%) alloys proceeded through two or three stages. I.e., by forming Al phase at the first stage of the low temperature side and by forming intermetallic compounds (Al3Ni, Al3Y) at the 2nd or 3rd stages of the high temperature side. The resulting Al particles smaller than l5nm and compounds larger than 50 nm in diameter were uniformly distributed in the amorphous matrix. The ultimate tensile and yield strengths of their alloys kept high value with a slight decrease from room temperature to 400K. Elongation Increased significantly from 2% at room temperature to over 20% at temperatures higher than crystallization temperature. DSC analysis shows that such a large elongation was originated from the precipitation of the crystalline phase. On the other hand, In Al88Ni10Y2 and Al86Ni10Y4 alloys which do not exhibit glass transition phenomenon, the deformation occurred through the shear deformation mode. However, with occurrence of glass transition (Al84Ni10Y6 alloy). the deformation mode was changed viscoelastic alloy.

Achieving high efficiency by high temperature annealing of hole transporting polymer layer in solution-processed organic light-emitting devices

Kim, T.Y.,Jung, J.H.,Kim, J.B.,Moon, D.G. Elsevier Sequoia] 2017 Synthetic metals Vol.232 No.-

We developed highly efficient solution-processed phosphorescent organic light-emitting device by annealing of hole transporting polymer layer at about glass transition temperature. Poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine) (poly-TPD) was used as a hole transporting polymer layer and tris(2-phenylpyridine)iridium(III) [Ir(ppy)<SUB>3</SUB>] doped N,N'-dicarbazolyl-3,5-benzene (mCP) was used as a solution-processed emission layer. The annealing temperature was critical to the well-defined interface between the poly-TPD and mCP:Ir(ppy)<SUB>3</SUB> layers. In addition, the carrier recombination was significantly enhanced by high temperature annealing of poly-TPD layer. A current efficiency of 61.5cd/A and an external quantum efficiency of 17.5% were achieved by annealing of poly-TPD layer at about glass transition temperature.

Temperature dependence of effective thermal conductivity and effective thermal diffusivity of Se90In10 bulk chalcogenide glass

Kedar Singh,Abhay Kumar Singh,N.S. Saxena 한국물리학회 2008 Current Applied Physics Vol.8 No.2

Measurement of eective thermal conductivity (ke) and eective thermal diusivity (ve) of twin pellets of Se90In10 bulk chalcogenideglass has been carried out in the temperature range from 303 to 323 K and cooling from 323 to 303 K using transient plane source (TPS)technique. In the heating process variation of eective thermal conductivity (ke) and eective thermal diusivity (ve) is observed. Bothquantities are found to be maximum at 313 K, which lies in the vicinity of glass transition temperature (Tg). During the cooling processkeand ve remain same at all temperatures. Such type of behavior shows thermal hysteresis in this sample, which can be explained on thebasis of structural change of the Se90In10 bulk chalcogenide glass.

분자동역학 전산모사를 통한 Epoxy/SiC 나노복합재의 유리전이 거동과 열탄성 물성변화에 대한 연구

최준명(Joonmyung Choi),유수영(Suyoung Yu),양승화(Seunghwa Yang),조맹효(Maenghyo Cho) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

Thermal stability and thermoelastic properties of cross-linked epoxy and epoxy/SiC nanocomposites are investigated through molecular dynamics simulations. In order to observe particle size effect on the glass transition temperature (Tg) and thermoelastic properties, nanocomposites having different particle size but same volume fraction of 5.7% are prepared. The glass transition range is estimated from the variation of the density during the cooling down simulation. From the slope of the temperature-density relation, thermal expansion coefficients (CTE) below and above the Tg are independently estimated. Also, the elastic moduli are calculated from the Parrinello-Rahman fluctuation method at various temperatures. As a result, addition of nanoparticle increases the Tg and elastic moduli, and decreases the CTE of pure epoxy matrix. In addition the thermoelastic properties of nanocomposites show prominent particle size effect below and above the Tg.