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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Materials Research
Journal Basic Information
Journal DOI :
The Materials Research Society of Korea
Editor in Chief :
Volume & Issues
Volume 3, Issue 6 - Dec 1993
Volume 3, Issue 5 - Oct 1993
Volume 3, Issue 4 - Aug 1993
Volume 3, Issue 3 - Jun 1993
Volume 3, Issue 2 - Apr 1993
Volume 3, Issue 1 - Feb 1993
Selecting the target year
A Stydy on the Preparation of Cu-Graphite Composite Powders
Oh, Jong-Kee ; Kim, Taek-Hoon ; Lee, Hwa-Yeong ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 103~110
Abstract It has been attempted to make the copper-graphite composites by deposition of copper on the surface of graphite through the hydrogen reduction of copper chlorides. Both KISH and natural graphites of less than 325 mesh were used as substrates and the hydrogen reduction also was conducted in the range of 350-50
. The distribution of copper on the surface of graphite was found to increase with the decrease of reduction temperature. In addition. the partial pressure of hydrogen played an important role in the overall rate of reduction which was substantially dominated by the chemical reaction on the surface of each particle. It was concluded that the reduction temperature should be maintained as low as possible to accomplish the well distribution of copper in the composites.
A Study on the Change of Microstructures by Heat-treatment in Mo-Hf-C Alloys
Yun, Guk-Yeong ; Kim, Hyeong-Gi ; Lee, Jong-Mu ; Park, Won-Won ; Choe, Ju ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 111~120
Abstract In this study, the Mo-Hf-O ingots containing 0.31-1.14at % Hf and 0.08-1.00at % 0 were prepared by plasma arc melting. The change of microstructure depending on the condition of heat treatmen~ was analysed by optical microscophy, auger electron microscophy, and transmission electron microscophy. Molybdenum powder with the oxygen content of 830ppm was compacted, and then melted. The oxygen content of molybdenum ingots was detected to be 40 -130ppm. As the contents of Hf and 0 increased, the grain size of ingots decreased. When molybdenum igot containing l.14at % Hf and 1.00at % C was heat treated, p-molybdenum carbide in grains was transformed into
-molybdenum carbide at 130
. Between 140
, the precipitation of hafnium carbide was due to the reaction of solute Hf and C, and the hafnium carbide was saturated at grain boundaries at 150
. When the sample was heat treated from 150
, Hafnium oxide more stable thermodynamically precipitated both at grain boundaries and in grains after hafnium carbide had been dissolved at grain boundaries.
On the Crystal Growth of Gap by Synthesis Solute Diffusion Method and Electroluminescence Properties.
Kim, Seon-Tae ; Mun, Dong-Chan ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 121~130
The GaP crystals were grown by synthesis solute diffusion method and its properties were investigated. High quality single crystals were obtained by pull-down the crystal growing ampoule with velocity of 1.75mm/day. Etch pits density along vertical direction of ingot was increased from 3.8
of the first freeze to 2.3
of the last freeze part. The carrier concentration and mobilities at room temperature were measured to 197.49cc
/V.sec and 6.75
, respectively. The temperature dependence of optical energy gap was empirically fitted to
/(373. 096+TJeV. Photoluminescence spectra measured at low temperature were consist with sharp line-spectra near band-gap energy due to bound-exciton and phonon participation in band edge recombination process. Zn-diffusion depth in GaP was increased with square root of diffusion time and temperature dependence of diffusion coefficient was D(Tl = 3.2
exp( - 3.486/
/sec. Electroluminescence spectra of p-n GaP homojunction diode are consisted with emission at 630nm due to recombination of donor in Zn-O complex center with shallow acceptors and near band edge emission at 550nm. Photon emission at current injection level of lower than 100m A was due to the band-filling mechanism.
Effects of the Precipitation of Carbides and Nitrides on the Texture Structures in Extra Low Carbon Steel Sheets containing B, Nb and Ti(ll)
Lee, Jong-Mu ; Yun, Guk-Han ; Lee, Do-Hyeong ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 131~139
Abstract Alloying elements such as AI, Ti, Nb and B in the extra low carbon AI-killed steel precipitate as nitrides or carbides and change the recrystallization texture structure of the steel during heattreatment with the result of strong effects on the deep drawability of the steel sheet. In this study the effects of fine precipitates such as nitrides and carbides on the texture of extra low carbon steels into which Ti, Nb, B, P, Si and Mn were added as alloying elements were investigated by means of TEM, SEM and optical microscopic analyses. Fine N
C and T
AIN precipitates are mainly observed in the steel containing both Nb and Ti, while fine AIN and coarse BN precipitates are observed in the Nb~containing steel and coarse T
precipitates are observed in the Ti-containing steel. The grain size of the Ti containing steel is larger than that of the Nb containing steel and that of the one containing both Nb and Ti.
Fracture behavior of DGEBA/MDA/SN System
Jo, Seong-U ; Sim, Mi-Ja ; Kim, Sang-Uk ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 140~144
Abstract To modify brittleness among the properties of thermosetting epoxy resin, a reactive additive. succinonitrile(SN) was introduced to Diglycidyl ether of bisphenol A(DGEBA)-4, 4'-methylene dianiline (MDA) system. Fracture behavior was microscopically studied during breaking of composite materials. As a result, post debond friction energy was the most significant for breaking the composite having glass fibres, pull-out energy was the next significant and debonding energy was the last. It was observed that shear stress between glass fibre and epoxy matrix was main factor for fracture behavior. Reactive additive, SN made shear stress deteriorated.
Effects of Succinonitrile on the Thermal Properties of diglycidyl ether of bisphenol A/ methylene dianiline system
Sim, Mi-Ja ; Kim, Sang-Uk ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 145~150
Abstract In order to improve the brittleness of diglycidyl ether of bisphenol A(DGEBA)/4, 4'-methylene dianiline(MDA) system, the reactive additive, succinonitrile(SN) was added to DGEBA/MDA system. In this case, thermal properties, glass transition temperature(Tg), thermal decomposition temperature(Td) and 5% weight loss temperature(
)were investigated according to the different SN contents and cure temperatures. Tg, Td and
decreased as the SN content was increased, but increased as the cure temperature was increased.
Patterning of Y-Ba-Cu-O thin films by rdactive ion etching(RIE)
Park, Jong-Hyeok ; Han, Taek-Sang ; Kim, Yeong-Hwan ; Choe, Sang-Sam ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 151~157
Abstract We have fabricated Y-Ba-Cu-O superconducting thin films by in-situ on-axis rf magnetron sputtering method using
nonstoichiometric target. Reactive ion etching (RIE) method was used in patterning the films. We have investigated the properties of patterned films, and compared the properties of the films before and after patterning. As the line width of the pattern decreases from 5
m to 2
m, a slight but not significant degradation in superconducting properties of the patterned films is observed. The bridge patterns are found to have clean edges and good electrical properties enough to be applied in device applications. From the result of this research, the possibility of submicron patterning by RlE is confirmed.
Effect of Underlying Poly-Silicon on the Thermal Staability of the Ti-silicide Film
Kim, Yeong-Uk ; Lee, Nae-In ; Go, Jong-U ; Kim, Il-Gwon ; An, Seong-Tae ; Lee, Jong-Sik ; Song, Se-An ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 158~165
Abstract To investigate the effect of underlying Si on the thermal stability of the TiS
films obtained by the solid-state reaction of the Ti film on as-deposited or on heat-treated poly-silicon and amorphous-silicon were annealed at 90
for various times. The poly-Si film was evaluated by XRD, SEM and TEM. The thermal stability of the TiS
film was evaluated by measuring the sheet resistance and microstructural evolution during furnace annealing. Agglomeration of the TiSi, film occurred more on amorphous-Si than on poly-Si. The thermal stability of the TiS
film was improved by annealing poly-Si. The Si layer crystallized from amorphous-Si has an equiaxed structure with the (111) preferred orientation whereas for as-deposited poly-Si has a columnar structure with the (110) orientation. Better thermal stability of the TiS
film can be obtained by the higher surface energy of underlying poly-Si.
The Crack Resistance for PSG and Pe-Sin Films in the Semiconductor Device
Ha, Jung-Min ; Shin, Hong-Jae ; Lee, Soo-Woong ; Kim, Young-Wug ; Lee, Jung-Kyu ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 166~174
Abstract The crack resistance of PSG(Phosphosilicate Glass) and PE-SiN(Plasma Enhanced CVD S
)films deposited on aluminium thin films on Si substrate was analyzed in this study. PSG was deposited by AP-CVD and PE- SiN by PE-CVD. All the films underwent repeated heat cycles at 45
for 30 min. Crack formation and development were examined between each heat cycle. The crack behavior was found to be closely related to the stresses in the films. The stress induced by the difference in thermal expansion behavior between the passivation layers and underlying aluminum film may cause the crack. Crack resistance decreases as the thickness of PSG films increases due to the high tensile stress of the films. Phosphorus in the PSG films releases tensile stress and consequently the stress of the films tends to show compressive stress. As a result, crack resistance increased as the concentratin of P in the PSG films increased. Crack resistance in the PE-SiN films also increased with compressive stress. An experimental model to predict crack generation in the PSG and PE-SiN films during heat cycle was suggested.
Magenetic Properties of Nd-Fe-B-Co-based Melt-spun Ribbons an dTheir Bonded Magents
Gang, Gye-Myeong ; Gang, Gi-Won ; O, Yeong-Min ; Song, Jin-Tae ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 175~184
Abstract Co-and/or AI-added Nd-Fe-B-based magnetic alloys were fabricated by using vacuum induction melting frunace, and melt-spun ribbons were made of the magnetic alloys with single roll rapid quenching method. The variation of magnetic properties of the melt-spun ribbons as a function of Cuwheel velocity (Vs) were investigated. Bonded magnets were made of the optimally quenched ribbon fragments, and the magnetic properties of the melt-spun ribbons and the bonded magnets were studied, relating to the microstructure and crystalline structure. Cu-wheel surface velocity had a strong effect on the magnetic properties of the melt-spun ribbons, and the maximum properties were obtained around Vs =20m/sec. The optimally quenched ribbon had a cellura-type microstructure, in which fine N
B grains were surrounded by thin Nd-rich phase. In case of a 2.1at% AI-added melt-spun ribbon, the magnetic properties were as follows: iHc, Br, and (BH)max were 15.5KOe, 7.8KG and 8.5MGOe respectively. And resin bonded magnets were fabricated by mixing optimally quenched ribbon fragments with 2.5wt % polyamide resin, compacting and binding at room temperature. The iHc, Br and (BH)max of bonded magnet were lO.2KOe, 4.4KG and 3.3MGOe respectively. And hot-pressed magnets were made by pressing the overquenched ribbons at high temperature. The magnetic properties of hot-pressed magnets were better than those of bonded magnets, and when the holding time was 8 minutes, the iHc, Br, and (BH)max of the hot-pressed magnet were 1O.8KOe, 7.3KG and 8.0MGOe respectively. Domain structure was mainly maze pattern, which means that the easy magnetization axis could be aligned, and the domain width of the hot-pressed magnets was smaller than that of bonded magnets.
Electrorheological effect on the dispersive system consisting of polarizable fine powder/dielectric oil
Kim, Sang-Guk ; Choe, Yun-Dae ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 185~192
Abstract Electrorheological effect on the dispersive system of polarizable fine powder/dielectric oil has been investigated. ER effect was explained divided into following 3 mechanisms; (1) surface conductance, (2) bulk conductance, and (3) induced polarization. Mathematical model which predicts the interactive force between two fine particles in the electrorheological fluid has been introduced based on the induced polarization mechanism. This model may provide guide to select materials for strong ER effect. The attractive force between two particles was calculated using the above model for the selected 7 materials such as ceramics, ferrites, polymers etc. From the calculation result, it was found that the ceramics and ferrites are good materials which show a strong ER effect.
Cross-sectional TEM Specimens Priparation of Precisely Selected Regions of Semiconductor Devices using Focused Ion Beam Milling
Kim, Jeong-Tae ; Kim, Ho-Jeong ; Jo, Yun-Seong ; Choe, Su-Han ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 193~196
A procedure for preparing cross-sectional specimens for transmission electron microscopy(TEM)by focused ion beam(FIB)milling of specific regions of semiconductor devices is outlined. This technique enables TEM specimens to be pripared at precisely preselected area. In-situ #W thin film deposition on the top surface of desired site is complementally used to secure the TEM specimens to be less wedge shaped, which is main shortcoming of previous FIB-assisted TEM sample preparation technique. This technique is quite useful for the TEM sample priparation for fault finding and the characterization of fabrication process associated with submicron contact technologies.
The Effect of Hole Size on the Failure Strength and Fracture Toughness in Polymer Matrix Composite Plates
Kim, Jeong-Gyu ; Kim, Do-Sik ;
Korean Journal of Materials Research, volume 3, issue 2, 1993, Pages 197~204
Abstract The effects of the hole size and the specimen width on the fracture behavior of several fabric composite plates are experimentally investigated in tension. Tests are performed on plain woven glass/ epoxy, plain woven carbon/epoxy and satin woven glass/polyester specimens with a circular hole. It is shown in this paper that the characteristic length according to the point stress criterion depends on the hole size and the specimen width. An excellent agreement is found between the experimental results and the analytical predictions of the modified failure criterion. The notched strength increase with an increase in the damage ratio, which is explained by a stress relaxation due to the formation of damage zone. When the unstable fracture occurred, the critical crack length equivalent for the damage zone is about twice the characteristic length. The critical energy release rate
is independent of hole size for the same specimen width. The variation of
according to the material system, fiber volume fraction and specimen width relates to the notch sensitivity factor.
increases with a decrease in the notch sensitivity factor, which can be explained by a stress relaxation due to the increase of damage zone.