• 한국재료학회지
• /
• 제7권12호
• /
• pp.1083-1088
• /
• 1997

RF스퍼터링법으로 제작한 비정질(Fe$_{1-x}$ Co$_{x}$)$_{89}$Zr$_{11}$자성박막의 자기특성을 Co농도 X에 따라 조사하였다. 130 Oe의 인가자기중 1$50^{\circ}C$에서 90분간 열처리하였을 때 X=0.4, 0.5부근의 박막은 높은 자왜를 나타냄에도 불구하고 양호한 연자기 특성을나타내었다. 특히 X=0.4의 박막에서는 0.25 Oe의 낮은 보자력이 나타났으며, 1MHz, 50mOe의 여기자기장에서 측정된 교류투자율은 900정도였다. 본 연구의 박막에서 얻어진 우수한 자기특성은 외부자기장의 인가에 의해 특성의 변화가 가능한 표면탄성파(surface acoustic wave)소자에 응용될 수 있을 것으로 기대된다.된다..된다.

• Transactions on Electrical and Electronic Materials
• /
• 제16권2호
• /
• pp.86-89
• /
• 2015

Uniform ZrO₂ nanoballs were synthesized at 700℃ using the inverse replication method through a colloid-imprinted carbon (CIC) template. The structural, dielectric, and conducting properties of the ZrO₂ nanoballs were investigated and compared with those of ZrO₂ film prepared by sol-gel method and powdered ZrO₂ chemical. Both the monoclinic and cubic phases were found in the ZrO₂ balls and film but the ZrO₂ chemical showed a monoclinic phase, where the cubic structure is known to be formed at above 2,300℃. ZrO₂ nanoballs showed the lower dielectric property of k = 21.2 at 1 MHz because the 8-coordinated cubic phase in the ZrO₂ nanoball produced lower polarization than the polarization of the 7-coordinated monoclinic ZrO₂ chemical (k = 23.6). The dielectric stability was maintained in each ZrO₂ ball, film, and chemical under the applied forward and reverse voltage range (−5 to +5 V) at 1 MHz. The ionic conductivities were 7.86 × 10⁻⁸/Ω·cm for ZrO₂ nanoballs, 3.29 × 10⁻⁸/Ω·cm for ZrO₂ chemical, and 6.70 × 10⁻⁵/Ω·cm for the thickness of 1,053 nm ZrO₂ film at room temperature with the electronic contribution being less than 0.006%.

• Elastomers and Composites
• /
• 제46권4호
• /
• pp.304-310
• /
• 2011

다리 구조 또는 비다리 구조의 메탈로센 촉매를 이용하여 새로운 구조의 poly(ethylene-ter-1-hexeneter-divinylbenzene) 삼원공중합체를 제조하였다. 다리구조의 rac-$Et[Ind]_2ZrCl_2$ 촉매가 비다리구조의 $Cp_2ZrCl_2$ 촉매보다 상대적으로 양호한 결과를 보여 주었다. 특히 조촉매/촉매 몰비가 3000일 때 촉매활성도는 8000(kg of polymer/$mol{\cdot}h$)이 넘는 매우 높은 수준의 활성도를 보여주었다. 또한, 중합 시간에 따라 중량 평균 분자량이 일정수준까지 점차 증가하는 경향을 나타내었고, 중합시간이 50분일 때 무정형 상태를 나타내었다. 삼원공중합체의 중량평균 분자량은 110,000~200,000, 밀도는 $0.85{\sim}0.89g/cm^3$ 수준이었다. 또한, 삼원 공중합체의 열적 성질과 구조를 확인하였다.

• Corrosion Science and Technology
• /
• 제8권2호
• /
• pp.89-92
• /
• 2009

Pure Ti as well as Ti-6Al-4V alloy exhibit excellent properties for dental implant applications. However, for a better biocompatibility it seems important to avoid in the composition the presence of V due to the toxic effects of V ion release. Thus Al and V free and composed of non-toxic element such as Nb, Zr alloys as biomaterials have been developed. Especially, Zr contains to same family in periodic table as Ti. The addition of Zr to Ti alloy has an excellent mechanical properties, good corrosion resistance, and biocompatibility. In this study, the electrochemical characteristics of Ti-Zr alloys for biomaterials have been investigated using by electrochemical methods. Methods: Ti-Zr(10, 20, 30 and 40 wt%) alloys were prepared by arc melting and homogenized for 24 hr at $1000^{\circ}C$ in argon atmosphere. Phase constitutions and microstructure of the specimens were characterized by XRD, OM and SEM. The corrosion properties of the specimens were examined through potentiodynamic test (potential range of -1500 ~ 2000 mV), potentiostatic test (const. potential of 300 mV) in artificial saliva solution by potentiostat (EG&G Co, PARSTAT 2273. USA).

• Journal of Magnetics
• /
• 제12권4호
• /
• pp.133-136
• /
• 2007

We have carried out the study of magnetocaloric effect for as-quenched and annealed $Fe_{91-x}Y_xZr_9$ alloys. Samples were prepared by arc melting the high-purity elemental constituents under argon gas atmosphere and by single roller melt spinning. These alloys were annealed one hour at 773 K in vacuum chamber. The magnetization behaviours of the samples were measured by vibrating sample magnetometer. The Curie temperature increases with increasing Y concentration (x=0 to 8). Temperature dependence of the entropy variation ${\Delta}S_M$ was found to appear in the vicinity of the Curie temperature. The results show that annealed $Fe_{86}Y_5Zr_9$ and $Fe_{83}Y_8Zr_9$ alloys a bigger magnetocaloric effect than that those in as-quenched alloys. The value is 1.23 J/kg K for annealed $Fe_{86}Y_5Zr_9$ alloy and 0.89 J/kg K for as-quenched alloy, respectively. In addition, the values of ${\Delta}S_M$ for $Fe_{83}Y_8Zr_9$ alloy is 0.72 J/Kg K for as-quenched and 1.09 J/Kg K for annealed alloy, respectively.

• 한국자기학회지
• /
• 제5권5호
• /
• pp.528-532
• /
• 1995

Ferromagnetic resonance experiments have been used to investigate the magnetic properties of amorphous $Co_{89.5}Zr_{10.5}$ thin films deposited by DC magnetron sputtering method. In the thickness range from $350\;{\AA}$ to $3,200\;{\AA}$, measurements were carried out in a static magnetic field perpendicular and parallel to the film plane and in a conventional 9.44 GHz spectrometer at room temperature. The ferromagnetic resonance spectra by the field perpendicular to the film plane showed standing spin wave. The spacing and the relative intensities between the various spin wave resonance peaks are analysed considering surface magnetic anisotropy. The surface magnetic anisotropy constant ($K_{so},\;K_{sd}$) of amorphous $Co_{89.5}Zr_{10.5}$ thin films are $0.02\;erg/\textrm{cm}^2$ and $0.55\;erg/\textrm{cm}^2$ respectively regardless of the film thickness except for $3,200\;{\AA}$ film. In case of $3,200\;{\AA}$ these values are $0.46\;erg/\textrm{cm}^2$ and $0.55\;erg/\textrm{cm}^2$ respectively.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2016년도 추계학술논문요약집
• /
• pp.89-90
• /
• 2016

• 한국세라믹학회지
• /
• 제33권1호
• /
• pp.1-6
• /
• 1996

A single phase Ba2(Ti8,472Zr0.528)O20 was prepared by the oxalate method from aqueous solution of BaCl2 TiCl4 and ZrOCl2. The structure ananlysis has been carried out by Rietveld analysis method at room temperature. Powder X-ray data of Ba2(Ti8,472Zr0.528)O20 was indexed with the triclinic lattice(a=7.4587 $\AA$ b=14.0672 $\AA$, c=13.3327 $\AA$, $\alpha$=89.87, $\beta$=79.45 ${\gamma}$=84.46) The R (Residual) values of structure refinement were in a range between 10.00 and 8.00 This analysis proved that the added Zr occupied Ti sites in th structure of Ba2Ti9O20. Ba2(Ti8,472Zr0.528)O20 has excellent dielectric properties(dielectric constant K=40.49 at 5.42 GHz Q=4621) so that it can be used as good microwave dielectric materials.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 추계학술대회 논문집
• /
• pp.73-73
• /
• 2009

In this paper, electrical properties in $ZrO_2$-based high-k metal MIM capacitors were studied. Linear voltage coefficient of capacitance (VCC) was 72.375 ppm/V, quadratic VCC was $174.581ppm/V^2$, temperature coefficients of capacitance was $111.01ppm/^{\circ}C$ at 100kHz and $89.497ppm/^{\circ}C$ at 1MHz, which indicate the temperature dependence of electrical parameter for MIM capacitors.

• 한국진공학회지
• /
• 제5권2호
• /
• pp.147-155
• /
• 1996

Optical properties of $TiO_2/M/Ag/M/TiO_2$ films have been changed with the diffusion barrier metal M. Optimum opticla properties of $TiO_2/M/Ag/M/TiO_2$ as the transparent heat mirror film, could be obtained with Ti among diffusion barrier metals of Ti, Cu, Zr and Al. $TiO_2/M/Ag/M/TiO_2$ film, which was fabricated by sputtering of 18 nm-thick $TiO_2$ and Ag, and 4nm-thick Ti, showed maximum transimittance of 89% at visible wavelength and infrared reflectance of 97% at wavelength of 3000 nm. Optical properties of this film was not degraded by Xenon-sunshine weather test for 240 hours. For specimens with barrier layers of Cu, Zr, and Al, degradation of optical properties by weather test was increased in a sequence of films with Cu, Zr, and Al barrier layers.