• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.186-189
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• 2005

This paper was designed to assess the adhesive properties of hard coatings on non-nitrided and nitrided various tool steels. Estimations of adhesion were done to scratch test which is mainly used in hard coating. The critical load(Lc) between coating and substrate is defined through analysis of frictional load vs. normal load curve, signals of acoustic emission and optical observations. Coatings employed in this study are TiN, CrN and TiAlN, tools as substrates are STD11, STD61 and SKH51. It was classified to substrates with/without nitrided layer and hard coatings on substrate were deposited by arc PVD. Results showed that harder substrates and coatings give higher values of critical loads.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.3
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• pp.101-104
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• 2004

It was realized that MC-XRD is useful for phase analyzing of inclusions in crystals because it can focus the X-Ray beam to the small particles sized dozens of $\mu\textrm{m}$ with high S/N ratio. By using this MC-XRD, needle-like inclusions which are seen generally in corundum crystals known as rutile was found to be the iron titanium oxide and iron oxide which has the chemical composition of $Fe_2TiO_4,\; Fe_2TiO_5,\; Fe_2O_3$respectively

• Journal of Hydrogen and New Energy
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• v.1 no.1
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• pp.48-54
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• 1989

Semiconductive property of the passivating $TiO_2$ film was investigated by measuring the impedance of passivated titanium electrode in a 0.1 N NaOH solution. The passive film was prepared galvanostatically with $10mA/cm^2$ at formation potential of 50 V in a 1 N $H_2SO_4$ solution. The impedance measurement was conducted by superimposing an ac voltage of 5 m V amplitude with the frequency ranging from 5 to 10000 Hz on a dc bias (applied potential). The donor distribution in the film was depicted from the analysis of the non-linear slope of Mott-Schottky plot. The region with nearly constant concentration of donors near the electrolyte/film interface amounts at about 60 percent of the total film thickness and donor concentration increases largely with distance from the surface in an inner region near the film/metal interface. In a region of the film/metal interface the donor concentration showed a frequency dependence greater than in a region of the electrolyte/film interface. The result of donor concentration against frequency suggests a transition from crystalline to amorphous state with distance from the electrolyte/film interface in the passivating $TiO_2$ films. This is also confirmed by the ac conductivity measurement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.60-63
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• 1997

Dieletric ailed piezoelectric properties of Pb[$Zr_{0.45}$/ $Ti_{0.5-x}$/L $u_{x}$ (M $n_{1}$3//S $b_{2}$3)$_{0.05}$] $O_3$(0$\leq$x $\leq$0.03) were investigated. The partial substitution of $Ti^{4+}$ by a L $u^{3+}$ permitted improvement of the piezoelectric constant( $d_{33}$ ), electromechanical coupling factor ( $k_{p}$ ) and dielectric constant($\varepsilon$$_{33}$ /Sup T/). The dielectric loss(tan $\delta$ ) increased and mechanical quality factor(Qm) decreased with an increase of x were observed. A new piezoelectric material for actuator application was developed at x=0.02 with $d_{33}$ =370$\times$10$^{-2}$ /C/N, $k_{p}$ =58.5%, $\varepsilon$$_{33}$ $^{T}$ =1321, $Q_{m}$ =714 and tan $\delta$ =0.98%.%..%.%.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1496-1498
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• 2003

The $(Sr_{0.85}Ca_{0.15})TiO_3$(SCT) thin films were deposited on Pt-coated electrode (Pt/TiN/$SiO_2$/Si) using RF sputtering method according to the deposition condition. The optimum conditions of RF power and Ar/$O_2$ ratio were 140[W] and 80/20, respectively. Deposition rate of SCT thin films was about 18.75[${\AA}/min$] at the optimum condition. The capacitance characteristics had a stable value within ${\pm}4[%]$. The drastic decrease of dielectric constant and increase of dielectric loss in SCT thin films were observed above 200[kHz].

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.1049-1052
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• 2007

Extremely sharp and uniform Transfer Mold FEAs with thin film low work function TiN emitter material have been fabricated by controlling the thickness of the coated emitter materials to realize high efficient, high reliable and low-cost vacuum nanoelectronic devices..Their tip radii are 8.3-13.8 nm. Turn-on electric fields of the Ni FEAs and TiN-FEAs resulted in the low electric field values of $31.6\;V/{\mu}m$ and $44.2V/{\mu}m$,respectively, at the short emitter/anode distance: less than $30\;{\mu}m$, which are lower than those of conventional FE As such as Spindt type FEAs and carbon nan otube FEAs The Transfer Metal Mold fabrication method is one of the best methods of changing emit ter materials with sharp and uniform emit ter shapes.

• Tribology and Lubricants
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• v.20 no.6
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• pp.306-313
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• 2004

Many of the current development in surface modification engineering are focused on multilayered coatings, which have the potential to improve the tribological properties. Four different multilayered coatings were deposited on AISI D2 steel in this study. The prepared samples are designed as $WC-Ti_{0.6}Al_{0.4}N,\;WC-Ti_{0.53}Al_{0.47}N,\;WC-Ti_{0.5}Al_{0.5}N\;and\;WC-Ti_{0.43}Al_{0.57}N$. The multilayered coatings were investigated with respect to coating surface and cross-sectional morphology, roughness, adhesion, hardness, porosity and tribological behaviors. Especially, wear tests of four multilayered coatings were performed by using a ball-on-disc configuration with a linear sliding speed of 0.017 m/sec and a normal load of 5.38 N load. The tests were carried out at room temperature in air by employing AISI 52100 steel ball $(H_R\;=\;66) $ having a diameter of 10 mm. The surface morphology, and topography of the wear scars of samples and balls have been determined by using scanning electron spectroscopy (SEM). Also, wear mechanism was determined by using SEM coupled with energy-dispersive spectroscopy (EDS). Results have showed an improved wear resistance of the $WC-Ti_{1-x}Al_xN$coatings with increasing of Al (aluminum) concentration.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1025-1025
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• 2006

• Journal of the Korean Magnetics Society
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• v.15 no.2
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• pp.109-112
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• 2005

Electronic and magnetic properties of $Ti_{1-x}M_xO_{2-\delta}$ (M=Co and Fe) thin films grown by sol-gel method have been investigated. Anatase and rutile $Ti_{1-x}Co_xO_{2-\delta}$ films were successfully grown on $Al_2O_3$ (0001) substrates and exhibited p-type electrical conductivity while the undoped films n-type conductivity. Room temperature vibrating sample magnetometry measurements on the anatase and rutile $Ti_{1-x}Co_xO_{2-\delta}$ films with same x ($=4.8 at.{\%}$) showed quite similar magnetic hysteresis curves with the saturation magnetic moment of $\~4 {\mu}_B$ per Co ion despite their differences in structural and electronic properties. Such giant magnetic moment is attributable to the unquenched orbital moment of the $Co^{2+}$ ions substituting the octahedral $Ti^{4+}$ sites. Similar ferromagnetic behavior was observed for $Ti_{1-x}Fe_xO_{2-\delta}$ films that are highly resistive compared to the Co doped samples. Saturation magnetic moment was found to decrease for higher x, i.e., $\~2$ and $\~1.5 {\mu}_B$ per Fe ion for x=2.4 and 5.8 at. $\%$, respectively. Conversion electron $M\ddot{o}ssbauer$ spectroscopy measurements predicted the coexistence of $Fe^{2+}$ and $Fe^{3+}$ ions at the octahedral sites of $Ti_{1-x}Fe_xO_{2-\delta}$.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.7
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• pp.72-78
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• 1998

This paper is focused on the fabrication of reliable novel antifuse, which could operate at low voltage along with the improvement in OFF and ON-state properties. The fabricated antifuse consists of Al/BaTi$_{2}$O$_{3}$/SiO$_{2}$/TiW-silicide structure. Through the systematic analyses for bottom metal and the intermetallic insulator, material and electri cproperties were investiaged. TiW-silicide as the bottom electrode had smooth surface with average roughness of 11.angs. at 10X10.mu.m$^{2}$ and was bing kept as-deposited SiO$_{2}$ film stable. Amorphous BaTi$_{2}$O$_{3}$ film as the another insulator was chosen because of its low breakdown strength (2.5MV/cm). breakdown voltage of antifuse is remarkably reduced by using BaTi$_{2}$O$_{3}$ film, and leakage current of that maintained low level due to the SiO$_{2}$ film. Low ON-resistance (46.ohm./.mu.m$^{2}$) and low programming voltage(9.1V) can be obtained in theses antifuses with 220.angs. double insulator layer and 19.6X10$^{-6}$ cm$^{2}$ area, while keeping sufficient OFF-state reliability (less than 1nA).