• Journal of Powder Materials
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• v.20 no.1
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• pp.24-32
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• 2013

The effect of carrier gases (He, $N_2$) on the properties of Ti coating layers were investigated to manufacture high-density Ti coating layers. Cold spray coating layers manufactured using He gas had denser and more homogenous structures than those using $N_2$ gas. The He gas coating layers showed porosity value of 0.02% and hardness value of Hv 229.1, indicating more excellent properties than the porosity and hardness of $N_2$ gas coating layers. Bond strengths were examined, and coating layers manufactured using He recorded a value of 74.3 MPa; those manufactured using $N_2$ gas had a value of 64.6 MPa. The aforementioned results were associated with the fact that, when coating layers were manufactured using He gas, the powder could be easily deposited because of its high particle impact velocity. When Ti coating layers were manufactured by the cold spray process, He carrier gas was more suitable than $N_2$ gas for manufacturing excellent coating layers.

• Tribology and Lubricants
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• v.37 no.2
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• pp.54-61
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• 2021

The effect of the sand blasting before TiAlN coating in the manufacture of WC hard metal alloy tips have been studied. For four different tips, according to the status of processing of the sand blasting and the coating, residual stress measurement by X-ray diffraction and several tests for mechanical properties have been conducted. The results suggest that there was no difference in static mechanical properties, such as hardness, surface roughness and elastic modulus, between two coatings. Furthermore, compressive residual stress was generated equally on their surfaces. Additionally, the compressive residual stress in substrate WC was found to increase greatly when subjected to sand blasting treatment. However, the compressive residual stress decrease after coating regardless of sand blasting treatment. Nevertheless, it is confirmed that the compressive residual stress generated in the coating after sand blasting is less than that in the non-sandblasting coating. This was attributed to the plastic deformation occurring in the WC substrate during coating after sand blasting. In contrast to the scratch test results, sand blasting was assumed to have a negative effect on the adhesion between the coating and substrate. This is because there is a high possibility of microcracks due to plastic deformation in the WC substrate under the coating after sand blasting.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.269-275
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• 2000

The fretting wear characteristics of TiN coated Zircaloy-4 tube were investigated experimentally The fretting wear experiment was performed using TiN coated Zircaloy-4 tube as the fuel rod cladding material and uncoated Zircaloy-4 tube as one of grids. TiN coating is probably one of the most frequently and successfully used PVD coatings for the mitigation of fretting wear. In this study, TiN coating by PVD was employed for improvement of Zircaloy-4 tube fretting characteristics. The fretting tester was designed and manufactured for this experiment. TiN coated Zircaloy-4 tube was used as the moving specimen, uncoated ZircaBoy-4 tube as the stationary one. The number of cycles, slip amplitude and normal load were selected as main factors of fretting wear. The results of this research showed that the wear volume of TiN coated Zircaloy-4 tube increased as number of cycles, normal load and slip amplitude increase but the quantity of volume was lower than the case of uncoated Zircaloy-4 tube pairs.

• Journal of the Korean institute of surface engineering
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• v.35 no.3
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• pp.165-171
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• 2002

TiN coating were deposited onto different WC-Co substrates using arc ion plating (AIP) technique. The structure and morphology for the deposited coating were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The adhesion behavior of the deposited TiN coating was investigated with a conventional scratch test. Effects of WC particle size and Co content on the adhesion strength between the deposited TiN coating and substrate were studied. During the scratch test, the value of critical load was dependent of WC particle size and Co content on substrate. As the WC particle size and Co content on substrate decreased, the critical load increased. The highest critical load, approximately 110N, was obtained at WC particle size of 1$\mu\textrm{m}$ and Co content of 10wt.%.

• Corrosion Science and Technology
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• v.22 no.4
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• pp.232-241
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• 2023

The mechanical properties of the hydrogen valve responsible for supplying and blocking hydrogen gas in a hydrogen fuel cell electric vehicle (FCEV) were researched. Mechanical properties by hydrogen embrittlement were investigated by coating chromium nitride (CrN) and titanium nitride (TiN) on aluminum alloy by arc ion plating method. The coating layer was deposited to a thickness of about 2 ㎛, and a slow strain rate test (SSRT) was conducted after hydrogen embrittlement to determine the hydrogen embrittlement resistance of the CrN and TiN coating layers. The CrN-coated specimen presented little decrease in mechanical properties until 12 hours of hydrogen charging due to its excellent resistance to hydrogen permeation. However, both the CrN and TiN-coated specimens exhibited deterioration in mechanical properties due to the peeling of the coating layer after 24 hours of hydrogen charging. The specimens coated at 350 ℃ presented a significant decrease in ultimate tensile strength due to abnormal grain growth.

• Journal of the Korean institute of surface engineering
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• v.37 no.3
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• pp.152-157
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• 2004

Ti-Al-N ($Ti_{75}$ $Al_{25}$ N) and Ti-Al-Si-N ($Ti_{69}$ $Al_{23}$ $Si_{8}$N) coatings synthesized by a DC magnetron sputtering technique were studied comparatively with respect to phase characterization and high-temperature oxidation behavior. $Ti_{69}$ $Al_{23}$ $Si_{ 8}$N coating had a nanocomposite microstructure consisting of nanosized(Ti,Al,Si)N crystallites and amorphous $Si_3$$N_4$, with smooth surface morphology. Ti-Al-N coating of which surface $Al_2$$O_3$ layer formed during oxidation suppressed further oxidation. It was sufficiently stable against oxidation up to about $700^{\circ}C$. Ti-Al-Si-N coating showed better oxidation resistance because both surface Ab03 and near-surface $SiO_2$ layers suppressed further oxidation. XRD, GDOES, XPS, and scratch tests were performed.

• Korean Journal of Materials Research
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• v.14 no.8
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• pp.558-564
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• 2004

In order to improve the low hardness and low wear resistance of Ti-6Al-4V alloy, plasma carburization treatment and CrN film coating were carried out. Effects of the plasma carburization and CrN coating were analyzed and compared with the non-treated alloy by mechanical and creep tests. After plasma carburization and CrN coating treatments, the carburized layer was about 150 ${\mu}m$ in depth and CrN coated layer was about 7.5 ${\mu}m$ in thickness. Hardness value of about $H_{v}$ 402 of the non-treated alloy was improved to $H_{v}$ 1600 and 1390 by plasma carburization and CrN thin film coating, respectively. Stress exponent(n) was decreased from 9.10 in CrN coating specimen to 8.95 in carburized specimen. However, the activation energy(Q) was increased from 242 to 250 kJ/mol. It can be concluded that the static creep deformation for Ti-6Al-4V alloy is controlled by the dislocation climb over the ranges of the experimental conditions.

• Korean Journal of Metals and Materials
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• v.50 no.12
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• pp.867-871
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• 2012

The microstructure and texture of TiN coatings on a Ni-based super-alloy were characterized by the automated version of electron backscatter diffraction (EBSD), EBSD techniques were used to investigate the very fine TiN grain shape and crystal orientation. This study confirmed that EBSD techniques provide a very useful tool for characterization of coating materials. The TiN grains had a special texture, a {001}-fiber texture in the coating layer. It was also found that, in severe environments, the coating performance of equiaxial and randomly oriented TiN is superior to that with columnar structures.

• Journal of the Korean institute of surface engineering
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• v.41 no.4
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• pp.147-155
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• 2008

The dental orthodontic wire provides a good combination of strength, corrosion resistance and moderate cost. The purpose of this study was to investigate the effects of TiN and ZrN coating on corrosion resistance and physical property of orthodontic wire using various instruments. Wires(round type and rectangular type) were used, respectively, for experiment. Ion plating was carried out for wire using Ti and Zr coating materials with nitrogen gas. Ion plated surface of each specimen was observed with field emission scanning electron microscopy(FE-SEM), energy dispersive X-ray spectroscopy(EDS), atomic force microscopy(AFM), vickers hardness tester, and electrochemical tester. The surface of TiN and ZrN coated wire was more smooth than that of other kinds of non-coated wire. TiN and ZrN coated surface showed higher hardness than that of non-coated surface. The corrosion potential of the TiN coated wire was comparatively high. The current density of TiN coated wire was smaller than that of non-coated wire in 0.9% NaCl solution. Pit nucleated at scratch of wire. The pitting corrosion resistance $|E_{pit}-E_{rep}|$ increased in the order of ZrN coated(300 mV), TiN coated(120 mV) and non-coated wire(0 mV).

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.3
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• pp.329-338
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• 2007

Purpose. The aim of this study is to evaluate the effect of TiN coating of abutment screw on the unscrewing torque. Material and methods. Titanium and Gold-Tite abutment screws were classified into two groups, Group A and C respectively, as control groups. Titanium abutment screws with TiN coatings were also classified into two groups, Group B and D, as experimental ones. Group A and B were tightened to 20 Ncm input torque, and Group C and D were tightened to 32 Ncm torque. Detorque values were measured with digital torque gauge during repeated closing and opening experiment. Results. Abutment screws with TiN coating (Group B and D) showed statistically significant higher mean detorque values than those of Group A and C. Discussion. Physical properties of TiN coating, such as low friction coefficient, high hardness and wear resistance, might contribute to higher detorque values. Conclusion. It is suggested that TiN coating of abutment screw help to reduce the risk of screw loosening and improve the stability of screw joint.