간행물
한국재료학회지 KCI 등재 SCOPUS Korean Journal of Materials Research
- 발행기관 한국재료학회
- 자료유형 학술지
- 간기 월간
- ISSN 2799-8525 (Print)2799-8681 (Online)
- 수록기간 1991 ~ 2024
- 주제분류 공학 > 재료공학 공학 분류의 다른 간행물
- 십진분류KDC 530DDC 620
권호리스트/논문검색
제18권 제3호 (2008년 3월) 10건
1.
2008.03
구독 인증기관 무료, 개인회원 유료
A 532 nm Nd-YAG laser was applied to crystallize amorphous Si thin films in order to evaluate the applicability of a Nd-YAG laser to low-temperature polycrystalline Si technology. The irradiation of a green laser was controlled during the crystallization of amorphous Si thin films deposited onto glass substrates in a sophisticated process. Raman spectroscopy and UV-Visible spectrophotometry were employed to quantify the degree of crystallization in the Si thin films in terms of its optical transmission and vibrational characteristics. The effectiveness of the Nd-YAG laser is suggested as a feasible alternative that is capable of crystallizing the amorphous Si thin films.
3,000원
2.
2008.03
구독 인증기관 무료, 개인회원 유료
Micro-sized bumps on a multi-layered build-up PCB were fabricated by pulse-reverse copper electroplating. The values of the current density and brightener content for the electroplating were optimized for suitable performance with maximum efficiency. The micro-bumps thus electroplated were characterized using a range of analytical tools that included an optical microscope, a scanning electron microscope, an atomic force microscope and a hydraulic bulge tester. The optical microscope and scanning electron microscope analyses results showed that the uniformity of the electroplating was viable in the current density range of 2-4 A/dm2; however, the uniformity was slightly degraded as the current density increased. To study the effect of the brightener concentration, the concentration was varied from zero to 1.2 ml/L. The optimum concentration for micro-bump electroplating was found to be 0.6 ml/L based on an examination of the electroplating properties, including the roughness, yield strength and grain size.
4,000원
3.
2008.03
구독 인증기관 무료, 개인회원 유료
The production of tin oxide (SnO2) microrods on iridium (Ir)-coated substrates was achieved through the thermal evaporation of Sn powders in which a sufficiently high O2 partial pressure was employed. Scanning electron microscopy revealed that the product consisted of microrods with diameters that ranged from 0.9 to 40 μm. X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction indicated that the microrods were SnO2 with a rutile structure. As the microrod tips were free of metal particles, it was determined that the growth of SnO2 microrods via the present route was dominated by a vapor-solid mechanism. The thickening of rod-like structures was related to the utilization of sufficiently high O2 partial pressure during the synthesis process, whereas low O2 partial pressure facilitated the production of thin rods.
4,000원
4.
2008.03
구독 인증기관 무료, 개인회원 유료
Evaluation of the solid surface properties by an analysis of the liquid penetration rate into powderbeds is very important in applications of powder products. The penetration rate is related the surface propertyin powder beds. In order to analyze the surface property of powders, the contact angle values of several powderswere obtained using the Washbun equation and the Wicking method. The surface free energy value γS wasdivided into a polar component γSp and a dispersion component γSd. Inorganic powders such as calcite were usedas test samples. The effects of the particle size and the type of experimental liquid on the penetration rate weremeasured. It was confirmed that the surface free energy of the grinding sample is smaller than that of theclassification sample.
4,000원
5.
2008.03
구독 인증기관 무료, 개인회원 유료
Blue-emitting BAM:Eu phosphor powders were formed by post-treatment of precursor powders with hollow or dense morphologies. The morphologies of the precursor powders obtained by spray pyrolysis were controlled by changing the preparation conditions and by changing the type of spray solution. The effects of the morphologies of the precursor powders on the characteristics of the BAM : Eu phosphor powders reacted with AlF3 flux were investigated. Precursor powders with a spherical shape and a hollow morphology produced BAM : Eu phosphor powders with a plate-like morphology, a fine size and a narrow size distribution. On the other hand, precursor powders with a spherical shape and dense morphology produced BAM : Eu phosphor powders with a plate-like morphology and a large size. AlF3 flux improved the photoluminescence intensities of the BAM : Eu phosphor powders. The photoluminescence intensity of the fine-sized BAM : Eu phosphor powders with a plate-like morphology was 90% of the commercial product under vacuum ultraviolet conditions.
4,000원
6.
2008.03
구독 인증기관 무료, 개인회원 유료
Fe compounds in scoria as distributed in the south-western area of Jeju Island were investigatedusing X-ray fluorescence spectroscopy, X-ray diffractometry, and 57Fe Mössbauer spectroscopy. The sampleswere prepared from four parasite volcanoes. It was found that these samples are typical basalt comprised ofSiO2, Al2O3, Fe, and silicate minerals. The Mössbauer spectra showed doublets for olivine, pyroxene, andilmenite as well as sextets for hematite and magnetite. The valence state of Fe is chiefly a 3+ charge statewith a slight 2+ charge state. It is expected that these results will add to the body of information related tothe formation mechanisms of Jeju Island.
4,000원
7.
2008.03
구독 인증기관 무료, 개인회원 유료
A new cost-effective atomic layer deposition (ALD) technique, known as Proximity-Scan ALD (PS-ALD) was developed and its benefits were demonstrated by depositing Al2O3 and HfO2 thin films using TMA and TEMAHf, respectively, as precursors. The system is consisted of two separate injectors for precursors and reactants that are placed near a heated substrate at a proximity of less than 1 cm. The bell-shaped injector chamber separated but close to the substrate forms a local chamber, maintaining higher pressure compared to the rest of chamber. Therefore, a system configuration with a rotating substrate gives the typical sequential deposition process of ALD under a continuous source flow without the need for gas switching. As the pressure required for the deposition is achieved in a small local volume, the need for an expensive metal organic (MO) source is reduced by a factor of approximately 100 concerning the volume ratio of local to total chambers. Under an optimized deposition condition, the deposition rates of Al2O3 and HfO2 were 1.3 Å/cycle and 0.75 Å/cycle, respectively, with dielectric constants of 9.4 and 23. A relatively short cycle time (5~10 sec) due to the lack of the time-consuming "purging and pumping" process and the capability of multi-wafer processing of the proposed technology offer a very high through-put in addition to a lower cost.
4,000원
8.
2008.03
구독 인증기관 무료, 개인회원 유료
Fe-aluminides have the potential to replace many types of stainless steels that are currently used in structural applications. Once commercialized, it is expected that they will be twice as strong as stainless steels with higher corrosion resistance at high temperatures, while their average production cost will be approximately 10% of that of stainless steels. Self-propagating, high-temperature Synthesis (SHS) has been used to produce intermetallic and ceramic compounds from reactions between elemental constituents. The driving force for the SHS is the high thermodynamic stability during the formation of the intermetallic compound. Therefore, the advantages of the SHS method include a higher purity of the products, low energy requirements and the relative simplicity of the process. In this work, a Fe-aluminide intermetallic compound was formed from high-purity elemental Fe and Al foils via a SHS reaction in a hot press. The formation of iron aluminides at the interface between the Fe and Al foil was observed to be controlled by the temperature, pressure and heating rate. Particularly, the heating rate plays the most important role in the formation of the intermetallic compound during the SHS reaction. According to a DSC analysis, a SHS reaction appeared at two different temperatures below and above the metaling point of Al. It was also observed that the SHS reaction temperatures increased as the heating rate increased. A fully dense, well-bonded intermetallic composite sheet with a thickness of 700 μm was formed by a heat treatment at 665˚C for 15 hours after a SHS reaction of alternatively layered 10 Fe and 9 Al foils. The phases and microstructures of the intermetallic composite sheets were confirmed by EPMA and XRD analyses.
4,000원
9.
2008.03
구독 인증기관 무료, 개인회원 유료
Eu3+-activated R3GaO6 (R=Y, Gd) phosphors were prepared in a conventional solid-state reactionand their optical properties were investigated. These compounds exhibit strong red emission under lightexcitation at 254nm. The emission spectra are dominated by peaks appearing around 610-630nm that areinduced by the electric dipole transition of 5D0→7F2 of Eu3+. In addition, the appropriate CIE (CommissionInternationale de l’clairage) chromaticity coordinates, (x=0.656, y=0.336) for Y3GaO6 and (x=0.655, y=0.334)for Gd3GaO6, become closer to the NTSC (National Television System Committee) standard values. With theoptimized activator concentrations, the maximum emission brightness is approximately 80% of Y2O3:Eu3+typical red-emitting phosphor with improved color purity under an excitation condition of 254nm.
3,000원
10.
2008.03
구독 인증기관 무료, 개인회원 유료
The morphology of three-dimensional (3D) cross-linked electrodeposits of copper and tin was investigated as a function of the content of metal sulfate and acetic acid in a deposition bath. The composition of copper sulfate had little effect on the overall copper network structure, whereas that of tin sulfate produced significant differences in the tin network structure. The effect of the metal sulfate content on the copper and tin network is discussed in terms of whether or not hydrogen evolution occurs on electrodeposits. In addition, the hydrophobic additive, i.e., acetic acid, which suppresses the coalescence of evolved hydrogen bubbles and thereby makes the pore size controllable, proved to be detrimental to the formation of a well-defined network structure. This led to a non-uniform or discontinuous copper network. This implies that acetic acid critically retards the electrodeposition of copper.
4,000원
