• 대한기계학회논문집A
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• 제28권5호
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• pp.547-553
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• 2004

A hemispherical asperity moving over a flat plane is simulated based on classical molecular dynamics. The asperity and the plane consist of silicon atoms whose interactions are governed by the Tersoff three-body potential. The gap between the asperity and the plane is maintained to produce attractive normal force in order to investigate the adhesive friction and wear. The simulation focuses on the influence of crystallographic orientation of the contacting surfaces and the moving direction. It is demonstrated that the adhesive friction and wear are lower when crystallographic orientations of the contacting surfaces are different, and also depend on the moving direction relative to the crystal1ographic orientation.

• 한국표면공학회지
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• 제31권4호
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• pp.217-222
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• 1998

The Facing Targets Sputtering(FTS) system has several advantages for preparing films over a wide range of working gas pressure on plasma-free substrates. Co-Cr thin films seem to be one of the most promising media for perpendicular magnetic recording system. In this study, the capabillities of the system fordepositing C0-Cr films have been investigated. Under various Ar gas pressure, films with morphologically dense microstructure and good c-axis orientation were deposited, even when the incident angle $\psi_x$ of sputtered part icles to the film plane was below abount $50^{\circ}C$. this may imply that the shadowing effect by obique incidence of particle can be compensated by rapid surface diffusion owing to the high kinetic energy of particles arriving at the growing film. It has been confirmed that the FTS system is very useful for perparing Co-Cr thin films recorging media.

• 한국표면공학회지
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• 제26권5호
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• pp.245-254
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• 1993

The effects of pulse current electrolysis conditions on the composition and the microstructure of Ag-Sn alloy were studied by using a pyrophosphate bath. Both cathode current efficiency and throwing power of alloy deposits formed under pulse plating conditions, decreased with increasing mean current density, and lower than those under D.C. electrolysis condition. Tin content of Ag-Sn alloy decreased noticebly with in-creasing the mean current density, while it increased with the increase of On-time from 1 to 10 ms. The pre-ferred orientation of Ag-Sn alloy changed with increasing cathode overpotential in the sequence of (100)longrightarrow(100)+(111)longrightarrow(111) at $20^{\circ}C$ and (110)longrightarrow(111)longrightarrow(111)+(100) at $30^{\circ}C$. The effective crystal grain size of the alloy was decreased by decreasing temperature from $30^{\circ}C$ to $20^{\circ}C$ and the surface structure of them was related to the preferred orientation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.6-8
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• 2002

In order to prepare magnetic recording layer with a good quality crystallographic characteristic. We prepared $Co_{77}Cr_{20}Ta_3$ layer for perpendicular magnetic recording media on slide glass substrate by Two-Step Methode. The thickness of magnetic layer was fixed 100 nm and buffer layer were varied from 10 to 50 nm, and input current was varied from 0.2[A] to 0.5[A]. The surface morphology and crystal orientation of the CoCrTa films were examined with XRD. Prepared thin films showed improvement of dispersion angle of c-axis orientation ${\Delta}{\theta}_{50}$ caused by inserting buffer layer.

• 한국전기전자재료학회논문지
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• 제20권11호
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• pp.969-976
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• 2007

In this thesis, an anchoring energy in the upper and lower substrates of TFT-LCD cell has been modeled and applied in the numerical calculation of the molecular orientation of the TN-LCD. The molecular orientation of liquid crystals defined as tilt and twist angles was simulated using the Newton-Raphson method and the Gaussian integration method. From the results, the tilt and twist angles for the strong anchoring energy were proven to be coincide with those of the conventional results. on the other hand, for the weak anchoring energy, azimuth angles of the molecules were changed abruptly from $0^{\circ}\;to\;90^{\circ}$ near the middle area of the cell due to the balance of the anchoring energy and the elastic energy of the liquid crystals.

• 한국표면공학회지
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• 제27권5호
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• pp.285-291
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• 1994

The effects of pulse current parameters on the composition and the microstructure of Pd-Ni alloy electrodeposits were studied. The cathode current efficiency of p.c. electrolysis conditions decreased with increasing both mean and peak current density and was lower than those under D.C. electrolysis condition. Palladium content of Pd-Ni alloy increased with increasing both peak current density and on-time, while it decreased with increasing mean current density and duty cycle. The preferred orientation of Pd-Ni alloys changed with increasing mean current density in the sequence of (111)+(110).(100) or (110)longrightarrow(111)longrightarrow(100) or random distribution of crystal structure. The surface morphology of Pd-Ni alloy changed mainly according to the mean current density and was related to the preferred orientation.

• 한국표면공학회지
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• 제30권2호
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• pp.128-135
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• 1997

The effect of the polyethyledglycol(PEG) on the surface morphology and crystal orientation of electrodeposited zinc from a chloride (1.5M Zinc+7.0M chloriode) have been studied by means of electrochemical methodes, scanning electron microscopy, surface appearance measurement and X-ray diffraction patterns. The resistance of electrodeposit increased, whereas the evolution of hydrogen decreased with incrasing of molecular weight of the PEG. Large grains of electrodeposit were obtained from bath in the absence of organid additive. When the PEG was added, fine grained crystals were observed and the surface roughness was relatively small, but surface appearance deteriorated. The preferred orientation with a(101) plane parallel to the surface was obtained from the PEG addited bath.

• 한국표면공학회지
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• 제33권5호
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• pp.339-348
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• 2000

The study was conducted on the effect of bath composition on the surface appearance, the hardness and the crystal orientation of zinc electrodeposits from the chloride bath. (1) The hardness of the zinc electrodeposits from the chloride bath was increased by suppressing mass transfer of zinc through adding the organic additives and the chlorine ion in the electrolyte. (2) The surface whiteness of zinc deposits was decreased due to the change of the preferred orientation from (002) , (103) to (101) , (100) through increasing the organic additives and chlorine ion in the electrolyte. (3) The addition of Cu, Sn, Ni or Co in the chloride bath elevated the hardness of the zinc deposits but darkened the surface whiteness. (4) The optimum condition of the organic additives and the chlorine ion for increasing the hardness of zinc deposits and preventing dark surface ranges 0.3 m1/1 to 0.4 m1/1 and 6.5 mol/1 to 6.8mol/l respectively.

• 열처리공학회지
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• 제32권1호
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• pp.1-11
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• 2019

In this study, microstructure evolution and crystallographic orientation are investigated under various deformation conditions in M1 magnesium alloy. M1 magnesium ingot was rolled at 673 K with the rolling reduction of 30%. The compression test specimens were machined out from rolled plate, and then the specimens were annealed at 823 K for 1h. Uniaxial compression tests were conducted at 723 K and under the strain rate ranging from $5.0{\times}10^{-4}s^{-1}$ to $5.0{\times}10^{-2}s^{-1}$ up to a true strain of -1.0. For observation of crystal orientation distribution, EBSD measurement was performed. Occurrence of the dynamic recrystallization and grain boundary migration were confirmed in all case of the specimens. The distribution of the grains is not uniformed in the experimental conditions.

• 한국진공학회지
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• 제6권S1호
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• pp.154-159
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• 1997

The crystal structure properties of TiN thin films deposited on SKD61 steel and Si(100) substrates by Ion Beam Assisted Deposition have been studied to clarify the thin film growth mechanism by using XRD, RBS, SEM, and AFM. The preferred orientation of TiN thin films changes from (111) to (100) as increasing the assisted energy. This tendency is independent of the substrate structure. The TiN thin film grow with (100) direction having surface free energy minimum as the assisted energy increases.