• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.27-34
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• 2001

A new functionally gradient metal coating method using an atomic mixing technique was developed. In this work the effect of silver atomic mixing on the tribological characteristics of silver$.$ films. has been investigated experimentally. Atomic mixing was implemented by using the, bombardment .of accelerated Ar ions during the thermal evaporation coating process of silver films. Experiments were performed in dry conditions using a ball-on-disk test rig at a load range of 19.6 mN - 17.64 N and a sliding velocity of 20 mm/sec. Results showed that the life of functionally gradient silver coating was enhanced about 100 times more than that of thermally evaporated silver coating and 2 times more than that of IBAD silver coating. The functionally gradient. film also showed low friction and wear compared to those of the evaporated silver and

• Korean Journal of Materials Research
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• v.5 no.5
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• pp.503-511
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• 1995

금속/실리콘계에 대한 이온선 혼합시의 비정질상 및 결정상 형성여부를 예측할 수 있는 모델(ADF Model)과초기 결정상 예측 모델(PDF Model)의 적용을 실험적으로 조사하기 위하여 Ni/Si계에 대한 이온선 혼합을 온도와 이온선량을 변수로 하여 행하였으며 상형ㅅㅇ과정을 해석하였다. 이온선 혼합은 80keV가속기를 이용하여 상온~20$0^{\circ}C$의 온도 범위에서 1.0 $\times$ $10^{15}$Ar^{+}$/$cm^{2}$~2.0 $\times$ $10^{-16}$Ar^{+}$/$cm^{2}$의 이온선량을 변화시키면서 실험하였고, 상분석은 TEM과 GXRD를 이용하였다. Ni/Si게에 대한 ADF값은 0.804로 양의 값을 가지므로 이온선 혼합시 비정실상이 형성되고, $Ni_{2}$Si상이 다른 화합물상보다 훨씬 큰 음의 PDF값을 갖으므로 초기 결정상이 $Ni_{2}$Si가 될 것을 예측하였다. 이러한 예측은 실험결과와 매우 잘 일치하였다. 이상의 연구결과로부터 ADF 및 PDF모델을 이용하여 박막에서 형성되는 상을 보다 정확히 예측할수 잇음을 알 수 있었다.

• Korean Journal of Optics and Photonics
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• v.2 no.3
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• pp.133-138
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• 1991

Eosin-doped boric acid glass saturable absorber has a relatively low saturation intensity (700 mW/$\textrm{cm}^2$) and low power optical phase conjugation is achived by the degenerate four-wave mixing (DFWM) experiments. Polarization properties of optical phase conjugation by DFWM have been demonstrated in this materials using a cw argon ion laser at wavelength 488 nm. The dependence of the phase conjugated reflectivity on the intensity and wavelength of the pump beam is examined. The magnitude of the energy exchange by the nondegenerate two-wave mixing (NDTWM) is maximized by frequency difference between the two beams of $\varphi\simeq$ 1100 Hz.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.101-101
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• 2010

A strong adhesion of a silicon carbide (SiC) coating on a WC-Co substrate was achieved through an ion beam mixing technique and the corrosion resistance of the SiC coated WC-Co was investigated by means of a potentiodynamic electrochemical test. In the case of 1 M NaOH solution, a corrosion current density for a SiC coated WC-Co with a heat treatment at $500^{\circ}C$ displays about 50 times lower than that for the as-received WC-Co. However, in the case of 0.5 M H2SO4 solution, a corrosion current density for a SiC coated WC-Co displays about 3 times lower than that for as-received WC-Co. We discussed the physical reasons for the changes of the corrosion current densities at the different electrolytes.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.162-162
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• 2000

We have studied magnetic properties of Co/Pt multilayered films which have attracted great interest as high-density magneto-optical (MO) recording media due to their good MO properties. For this study, [Pt(45 )/Co(35 )]$\times$8 films were deposited with a Pt buffer layer of 60 on Si(100) substrate by alternating electron-beam evaporation in a high vacuum and were ion beam mixed by using 80keV Ar+ at 25$0^{\circ}C$. Especially, an external magnetic field was added to help changing magnetic property during ion beam mixing (IBM). The intermixing of Co and Pt layers after IBM was confirmed with Rutherford Backscattering Spectroscopy (RBS) and Transmission Electron Microscopy (TEM). The MO property of the film was measured with magneto-optical Kerr spectrometer and the change of magnetic easy axis in the film plane was observed from Ker loop data. This anomalous result might be correlated with the change of atomic structure due to the intermixing effect.

• Nuclear Engineering and Technology
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• v.40 no.3
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• pp.233-238
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• 2008

This study investigates the surface modification of a Hastelloy X plate and diffusion bonding in the assembly of surface modified plates. These types of plates are involved in the key processes in the fabrication of a process heat exchanger (PHE) for a $SO_3$ decomposer. Strong adhesion of a SiC film deposited onto Hastelloy X can be achieved by a thin SiC film deposition and a subsequent N ion beam bombardment followed by an additional deposition of a thicker film that prevents the Hastelloy X surface from becoming exposed to a corrosive environment through the pores. This process not only produces higher corrosion resistance as proved by electrolytic etching but also exhibits higher endurance against thermal stress above 9$900^{\circ}C$. A process for a good bonding between Hastelloy X sheets, which is essential for a good heat exchanger, was developed by diffusion bonding. The diffusion bonding was done by mechanically clamping the sheets under a heat treatment at $900^{\circ}C$. When the clamping jig consisted of materials with a thermal expansion coefficient that was equal to or less than that of the Hastelloy X, sound bonding was achieved.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1268-1270
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• 1994

Fine lithographic technology in a submicron design regime is necessary for the fabrication of VLSI circuits. In such lithography, fine pattern delineation is performed by electron beam, ion beam and X-ray lithography instead of photolithography. Therefore, the new resist materials and development method have been required. So, we are investigating another positive E-beam resists which have high sensitivity and dry etching resistance, Plasma co-polymerized resist was prepared using an interelectrode gas-flow-type reacter. Methymethacrylate, tetramethyltin and styrene were chosen as the monomer to be used. The delineated pattern in the resist was developed with gas-flow-type reactor using an argon and 02 as etching gas. We studied about the effects of discharge power and mixing rate of the co-polymerized thin :film. The molecular structure of thin film was investigated by ESCA and IR, and then was discussed in relation to its quality as a resist.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.1
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• pp.46-50
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• 2002

C-SiC films with different content of SiC on stainless steel substrate were prepared with ion beam mixing. It was found that hydrogen concentrations in C-SiC coatings was higher than that in stainless steel after H$\^$+/ ion implantation followed by thermal annealing. Infrared (IR) transmission measurement was used to study the mechanism of hydrogen retention by C-SiC films. The vibrational features in the range between 400 and 3200 cm$\^$-1/ in IR transmission spectra show the Si-CH$_3$, Si-CH$_2$, Si-H, CH$_2$and CH$_3$bonds, which are responsible for retaining hydrogen.

• Korean Journal of Optics and Photonics
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• v.9 no.6
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• pp.423-427
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• 1998

Two wave mixing experiments in $LiNbO_3$, $BaTiO_3$ are carried out, and the characteristics as optical information processing device are investigated. Examined crystals are commonly used ones, such as 0.03% mol Ce-doped $BaTiO_3$, 0.03% mol Fe-doped $LiNbO_3$, and 6% mol MgO-doped $LiNbO_3$. $Ar^+$ ion laser is used as the writing beam, and He-Ne Laser is used as the reading beam. The recording-decay and erasing characteristics of diffraction gratings, the time constants, and also the angular selectivities are measured for each crystals and compared.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.164-164
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• 2000

Since Au-Pt alloys have various atomic structures depending upon composition and annealing temperature, it is very interesting to investigate the electronic structures of alloys. We studied the changes of the electronic structure I the Au-Pt alloys by x-ray absorption near edge spectroscopy (XANES). Two kinds of Au-Pt alloy samples were prepared by arc melting methods and ion-beam-mixing technique. The Pt L2, 3-edge and Au L2, 3-edge X-ray absorption spectra (XPS) were measured with the electron yield mode detector at the 3C1 beam line of the Pohang Light Source (PLS). It was found that there was a substantial decrease in the area of the Pt L2, 3 white lines compared with that of pure Pt. The observed decrease in white line area was attributed to an increase in the number of pure Pt. The observed decrease in white line area was attributed to an increase in the number of 5d-electrons at the Pt site upon alloy formation. However, the Au L2, 3 edge spectra for Au-Pt alloys are all similar to that of pure Au. This implies that the 5d hole count of Au is not changed by alloy formation with Pt.