• Tribology and Lubricants
• /
• 제15권4호
• /
• pp.328-334
• /
• 1999

Acoustic emission (AE) sensor was used to evaluate the wear-life of CrN-coated steel disks with 1 $\mu\textrm{m}$ and 4 $\mu\textrm{m}$ coating thickness. The relationship between Af and friction signal from scratch test and sliding test was investigated. The first spatting of CrN film was detected by AR signals in the early stage of coating failures, and overall failures by friction signals. Therefore, the conservative design for coating-life should be done using the results of AE signals. Using the percent contact load, the ratio of sliding normal load to the critical scratch load and the number of cycles to failure was measured to predict the wear-life of CrN film. On the wear-life dia-gram the percent contact loads and the number of cycles to failure showed a good linear relationship on the log coordinate. As the load percentage was decreased, the diagram showed that the wear-limits, at which the coated steels survived more than 35,000 cycles, were about 4∼5% of the critical scratch loads.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 한국소성가공학회 2005년도 추계학술대회 논문집
• /
• pp.178-181
• /
• 2005

Quaternary Ti-Si-C-N coatings were deposited on WC-Co substrates by a hybrid coating system of arc ion plating (AIP) and sputtering techniques using Ti and Si targets, in an $Ar/N_2/CH_4$ gaseous mixture. The crystallinity, bending status, and microstructure of the Ti-Si-C-N coatings were measured by X-ray diffractometer (XRD) and X-ray photoelectron spectroscope (XPS), The micro-hardness of Ti(C,N) and Ti-Si-N coatings were about 30 and 40 GPa, respectively. As the Si was incorporated into Ti(C,N) coatings, the Ti-Si-C-N coatings having Si content of $8.9\;at.\%$ showed the maximum hardness value of about 55 GPa. In this work, the microstructure and mechanical properties of Ti-Si-C-N coatings were systematically investigated.

• ETRI Journal
• /
• 제31권6호
• /
• pp.675-679
• /
• 2009

$Ti_xSi_{1-x}O_y$ (TSO) thin films are fabricated using plasma-enhanced atomic layer deposition. The Ti content in the TSO films is controlled by adjusting the sub-cycle ratio of $TiO_2$ and $SiO_2$. The refractive indices of $SiO_2$ and $TiO_2$ are 1.4 and 2.4, respectively. Hence, tailoring of the refractivity indices from 1.4 to 2.4 is feasible. The controllability of the refractive index and film thickness enables application of an antireflection coating layer to TSO films for use as a thin film solar cell. The TSO coating layer on an Si wafer dramatically reduces reflectivity compared to a bare Si wafer. In the measurement of the current-voltage characteristics, a nonlinear coefficient of 13.6 is obtained in the TSO films.

• Journal of the Korean institute of surface engineering
• /
• 제42권5호
• /
• pp.220-226
• /
• 2009

Cr-O-N coatings having different oxygen contents were deposited on Si wafer and SUS 304 substrates by an arc ion plating technique using Cr target in $Ar/O_2/N_2$ gaseous atmosphere. As increasing oxygen content in the coating, the microstructure of Cr-O-N coating changed from polycrystalline having NaCl structure to amorphous structure. Further increase of oxygen content resulted in phase transformation from amorphous to rhombohedral structure. From the variations of d value and average grain size, it was revealed that the maximum solubility of oxygen in Cr-O-N coating was about 21 at.%. And the maximum micro-hardness of 2751HK was obtained in this composition. The lowest friction coefficient was measured in the coating having 34.8 at.% of oxygen. However, more narrow width of wear track was found in the coating having 30.1 at.% of oxygen.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 한국소성가공학회 2009년도 춘계학술대회 논문집
• /
• pp.278-281
• /
• 2009

Selective laser sintering(SLS), a kind of rapid prototyping technology, can provide a process to form many types of coatings. Coated layers by selective laser melting are highly influenced by substrate, powder and laser parameters such as laser power, scan rate, fill spacing and layer thickness. Therefore an attempt to fabricate Fe-Ni-Cr coating on AISI H13 tool steel has been performed by selective laser sintering. In this study, Fe-Ni-Cr coating was produced by experimental facilities consisting of a 200W fiber laser which can be focused to 0.08mm and atmospheric chamber which can control atmospheric pressure with Ar. With power increase or energy density decrease, line width was decreased and line surface quality was improved with energy density increase. Surface quality of coating layer was improved with fill spacing optimization or layer thickness decrease.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• 제31권4호
• /
• pp.244-248
• /
• 2018

We propose a method for improving the reliability of a solar cell by applying a fluorinated surface coating to protect the cell from the outdoor environment using an atmospheric pressure plasma (APP) treatment. An APP source is operated by radio frequency (RF) power, Ar gas, and $O_2gas$. APP treatment can remove organic contaminants from the surface and improve other surface properties such as the surface free energy. We determined the optimal APP parameters to maximize the surface free energy by using the dyne pen test. Then we used the scratch test in order to confirm the correlation between the APP parameters and the surface properties by measuring the surface free energy and adhesive characteristics of the coating. Consequently, an increase in the surface free energy of the cover glass caused an improvement in the adhesion between the coating layer and the cover glass. After treatment, adhesion between the coating and cover glass was improved by 35%.

• Korean Journal of Optics and Photonics
• /
• 제8권6호
• /
• pp.466-470
• /
• 1997

We fabricated the asymmetric Fabry-Perot etalon which contains amorphous $As_2S_3$ as a spacer layer by using the method of optical multilayer coating and observed the optical bistability with the polarization. Optical thickness of the spacer layer is 2$\lambda$ at $Ar^+$ ($\lambda $=514.5 nm) laser wavelength. Optical bistability was observed at the intensities between 80~100 mW and the experiment shows us that the trends of bistable loop of the reflected and the transmitted lights are quite different depending on the state of polarization. This phenomena can be explained as the phase differences of each polarizations are different in the nonlinear Fabry-Perot etalon.

• Journal of the Korean institute of surface engineering
• /
• 제31권5호
• /
• pp.251-260
• /
• 1998

Stainless Steel is being used widely for various purposes due to its good corrosion resistance. There have been many researches to produce colored stainless steel by several methods such as anodizing and ion-plating. In this experiment, we $Ti_XN$(C,O) on the films SUS304, aluminium, and glass substrates with DC magentron sputterinng system made by Leybold Hereus, and strdied the structur, corrsion and pit characture of the TiXN observed by TeM image was black and whink and white columnar hed a very fine(200$\AA$) dense sturcture,and the diffraction resistance at the $3{\times}10_6A/\textrm{cm}^2$ and $10_{10}\times{cm}^2$current density were obtained in the under-stoichiometry $Ti_xN$ compound of Ar/$N_2$(Ar:$N_2$=100:6, titanium-rich compound) and the over-stoichiometry compound of Ar/$N_2$((Ar:$N_2$=60:15) respectively. When the thiness was over 1.64$\mu\textrm{m}$, good pit resistance could be obtained and its improvement was especially affected by perfect surfaceface. Typical TiN anodic polarzation curves of very unstable corrosion were observed by $Ti_xN$ film on the glass and perfect film of 3.28$\mu\textrm{m}$ thickness.

• Journal of the Korean Society for Heat Treatment
• /
• 제18권5호
• /
• pp.281-287
• /
• 2005

Titanium aluminium nitride((TiAl)N) film is anticipated as an advanced coating film with wear resistance used for drills, bites etc. and with corrosion resistance at a high temperature. In this study, (TiAl)N thin films were deposited both at room temperature and at elevated substrate temperatures of 573 to 773 K by using a two-facing-targets type DC sputtering system in a mixture Ar and $N_2$ gases. Atomic compositions of the binary Ti-Al alloy target is Al-rich (25Ti-75Al (atm%)). Process parameters such as precursor volume %, substrate temperature and Ar/$N_2$ gas ratio were optimized. The crystallization processes and phase transformations of (TiAl)N thin films were investigated by X-ray diffraction, field-emission scanning electron microscopy. The microhardness of (TiAl)N thin films were measured by a dynamic hardness tester. The films obtained with Ar/$N_2$ gas ratio of 1:3 and at 673 K substrate temperature showed the highest microhardness of $H_v$ 810. The crystallized and phase transformations of (TiAl)N thin films were $Ti_2AlN+AlN{\rightarrow}TiN+AlN$ for Ar/$N_2$ gas ratio of 1:3, $Ti_2AlN+AlN{\rightarrow}TiN+AlN{\rightarrow}Ti_2AlN+TiN+AlN$ for Ar/$N_2$ gas ratio of 1:1 and $TiN+AlN{\rightarrow}Ti_2AlN+TiN+AlN{\rightarrow}Ti_2AlN+AlN{\rightarrow}Ti_2AlN+TiN+AlN$ for Ar/$N_2$ gas ratio of 3:1. The above results are discussed in terms of crystallized phases and microhardness.

• Journal of the Korean institute of surface engineering
• /
• 제35권6호
• /
• pp.415-421
• /
• 2002

Ti-Si-N coating layers were codeposited on silicon wafer substrates by a DC reactive magnetron sputtering technique using separate titanium and silicon targets in $N_2$/Ar gas mixtures. The oxidation behavior of Ti-Si-N coating layers containing 4.0 at.%, 10.0 at.%, and 27.3 at.% Si was investigated at temperatures ranging from 600 to $960^{\circ}C$. The coating layers containing 4.0 at.% Si became fast oxidized from $600^{\circ}C$ while the coating layers containing 10.0 at.% Si had oxidation resistance up to $800^{\circ}C$. It was concluded that an increase in Si content to a level of 10.0 at.% led to the formation of finer TiN grains and a uniformly distributed amorphous Si3N4 phase along grain boundaries, which acted as efficient diffusion barriers against oxidation. However, the coating layers containing 27.3 at.% Si showed relatively low oxidation resistance compared with those containing 10.0 at.% Si. This phenomenon would be explained by the existence of free Si which was not nitrified in the coating layers containing 27.3 at.% Si.