• Journal of the Korean Ceramic Society
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• v.45 no.6
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• pp.345-349
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• 2008

$TiO_2$ coating ceramic tile for self-cleaning purpose was prepared by the precipitant dropping method using $TiCl_4$ as a precursor. $TiO_2$ film was formed on the ceramic tile by spray-coating technique and heat-treated at $500^{\circ}C$ for 1 h. The size and crystalline structure of $TiO_2$ particles were 15.3 nm and anatase phase. The outdoor exposure tests were conducted and the effects of outdoor exposure test conditions, such as exhaust concentration of contamination materials (test places), the UV light intensity (irradiation direction) and coating amounts of $TiO_2$ on the self-cleaning properties were investigated by the brightness measurements. As a results, self-cleaning property of $TiO_2$ coating tile was affected by the coating amount of $TiO_2$ however, not affected by the UV light intensity included in sun's ray (irradiation direction). $TiO_2$ coating ceramic tile can be utilized for exterior finishing materials because of self-cleaning property of $TiO_2$ coating tile.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.1
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• pp.7-10
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• 2002

$TiO_2$ thin films were prepared by coating and subsequent pyrolysis processes using Titanium-naphthenate as a raw material. $TiO_2$ thin films were made by spin-coating technique on the glass substrates, and heat treated at 45$0^{\circ}C$, The transmittance, refractive index, crystallinity and surface morphology of the $TiO_2$ thin films were measured by UV/Vis spec trophotometer, x-ray diffractometer and scanning electron microscope. $TiO_2$thin films on the slide glass showed the trans mittance of 70-90% and refractive index of 2.6 at 420 nm. The results of XRD and SEM showed that the $TiO_2$ thin films exhibited the anatase phase and the thread-like surface morphology.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.776-782
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• 2015

$TiO_2-SnO_2$ nanoparticles with an average diameter of 3~5 nm were synthesized by hydrolysis of titanium tetraisopropoxide (TTIP) and tin chloride to depress the photocatalytic activity of $TiO_2$ nanoparticles. Organic-inorganic hybrid coating solutions were prepared by reacting the $TiO_2-SnO_2$ nanoparticles with 3-glycidoxypropyl trimethoxysilane (GPTMS) by the sol-gel method. The hard coating films with high refractive index were obtained by curing thermally at $120^{\circ}C$ after spin-coating the coating solutions on the polycarbonate (PC) sheets. The coating films from $TiO_2-SnO_2$ nanoparticles showed an improved pencil hardness of 3H compared to 2H of the coating films from $TiO_2$ nanoparticles. Besides, the refractive index of the coating films from $TiO_2-SnO_2$ nanoparticles enhanced from 1.543 to 1.623 at 633 nm as the Sn/Ti molar ratio increased from 0 to 0.5.

• Journal of Welding and Joining
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• v.10 no.4
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• pp.213-221
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• 1992

Al$_{2}$O$_{3}$ ceramic coating layer by gas flame spraying was very porous, therefore it could not have wear and corrosion resistance at all. To get a dense and strong coating layer, a method to infiltrate an alloy into the pores of $Al_{2}$O$_{3}$ ceramic coating was investigated. Cu-Ti alloys, which had good wettability and reactivity with $Al_{2}$O$_{3}$ ceramic, were examined for infiltration. Infiltration of the alloys was performed in vacuum at 1100.deg.C. The melt of Cu-50 at % Ti alloy was well penetrated through the porous $Al_{2}$O$_{3}$ coating and tightly sealed the pores, unbounded area and microcracks in the coating. The alloy melt in the pores reacted with $Al_{2}$O$_{3}$ ceramic to produce a suboxide phase, Cu$_{2}$Ti$_{4}$O. This composite layer which was composed of $Al_{2}$O$_{3}$ and Cu$_{2}$Ti$_{4}$O phase had good microstructure and wear and corrosion resistance. Additionally, microstructures at interfaces between coating layers were greatly improved owing to the effect of vacuum heat treating.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.69-77
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• 2001

Wear and Friction characteristics of plasma-sprayed Cr$_2$O$_3$ coating and Cr$_2$O$_3$ coating included SiO$_2$ and TiO$_2$ against SiC ball have been investigated under different loads. Worn surfaces were observed by SEM and worn surfaces were analyzed by EDS. The Friction coefficient and the Wear resistance of Cr$_2$O$_3$-5SiO$_2$-3TiO$_2$coating was less than that of Cr$_2$O$_3$ coating. The main mechanisms were plastic deformation and brittle fracture. The film on surface were made by plastic deformation and compacted wear debris. This film protect wear of coating

• Korean Journal of Materials Research
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• v.12 no.5
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• pp.334-340
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• 2002

$TiO_2$-coated fly ash was synthesized by dropping method of coating agent in order to get $TiO_2$ coating layer with high photocatalytic activity on the surface of coal fly ash. The properties of the $TiO_2$ coating layer such as morphology, crystal structure, crystal size and photocatalytic activity were compared with those of the $TiO_2$-coated fly ash prepared by the traditional method of precipitation. $TiCl_4$ aqueous solution was used as a titanium stock solution and $NH_4HCO_3$ was used as a precipitant. The $TiO_2$ coating layer obtained by dropping method of coating agent was more uniform than that coated by precipitation. However, the crystal of $TiO_2$ coated by dropping method of coating agent was easy to grow by heat treatment because of the small primary particle size and bulky morphology, and its photocatalytic activity was consequently lower than that of the $TiO_2$ coated by precipitation. The $TiO_2$ coating layer obtained by both methods had a crystal structure of anatase, and the temperature of phase transformation into rutile was 90$0^{\circ}C$. The minimum crystal size of $TiO_2$ for the highest photocatalytic activity was found to be about 10nm.

• Corrosion Science and Technology
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• v.14 no.2
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• pp.64-75
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• 2015

Single $TiO_2$ coating prepared by sol-gel process usually experiences cracks in coating layer. In order to prevent cracks, an inorganic-organic hybrid $TiO_2-SiO_2$ coating was synthesized by combining precursors with an organic functional group. Five different coatings with various ratios of (1:8, 1:4, 1:1, 1:0.25 and 1:0.125) titanium alkoxide (TBOT, Tetrabutylorthotitanate) to organo-alkoxysilane (MAPTS, ${\gamma}$-Methacryloxy propyltrimethoxysilane) on carbon steel substrate were made by sol-gel dip coating. The prepared coatings were analyzed to study the coating properties (surface crack, thickness, composition) by scanning electron microscope (SEM), focused ion beam (FIB), and Fourier transform infrared spectroscopy (FT-IR). Potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) were also performed to evaluate the corrosion characteristics of the coatings. Crack free $TiO_2-SiO_2$ hybrid coatings were prepared with the optimization of the ratio of TBOT to MAPTS. The corrosion rates were significantly decreased in the coatings for the optimized precursor ratio without cracks.

• Korean Journal of Materials Research
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• v.15 no.7
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• pp.444-447
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• 2005

In this study, $Hydroxyapatite+TiO_2(HAp+TiO_2)$ composite sol coatings on Cp-Ti substrates were deposited by using a sol-gel derived precursor. Prior to hydroxyapatite coating, the samples were micropolished and divided into three sets. The first set was coated with hydroxyapatite (HAp) directly on Cp-Ti. The second set was first coated with intermediate titania layer and then coated with HAp. The third set samples were coated with $HAp+TiO_2$ (50:50) composite sol. Each samples were predried at $200^{\circ}C$, and heat treated at $600^{\circ}C$. The formation of hydroxyapatite has been confirmed by XRD analyses and the substrate material was found to be oxidized with negligible amount of CaO in the coating. The NaOH treated samples showed the presence of rutile crystal. The SEM studies revealed surface morphologies of each samples. $HAp+TiO_2$ composite sol coating layer was found to be smooth. The bonding strength of each samples were calculated using pull out tests. The bonding strength of the $HAp+TiO_2$ composite sol coating on substrate was 29.35MPa.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.10a
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• pp.183-190
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• 1997

The wear behaviors of $Al_2O_3-40%TiO_2$ deposited on casting aluminum alloy(ASTM A356) by plasma spray against SiC ball have been investigated experimentally. Friction and wear tests are carried out at room temperature. The friction coefficient of $Al_2O_3-40%TiO_2$ coating is lower than that of pure $Al_2O_3$ coating(APS). It is found that low friction correspond to low wear and high friction to high wear in the experimental result. The thickness of $Al_2O_3-40%TiO_2$ coatings indicated the existence of the optimal coating thickness. It is found that a voids and porosities of coating surface result in the crack generated. As the tensile stresses in coating increased with the increased friction coefficient. The columnar grain of coating will be fractured to achieve the critical stress. It is found that the cohesive of splats and the porosity of surface play a role in wear characteristics. It is suggested that the mismatch of thermal expansion of substrate and coating play an important role in wear performance. Tensile and compressire under thermo-mechanical stress may be occurred by the mismatch between thermal expansion of substrate and coating. This crack propagation above interface is observed in SEM.

• Journal of the Korean institute of surface engineering
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• v.52 no.4
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• pp.187-193
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• 2019

Electroless Ni-P coatings are widely used in the chemical, mechanical, and electronic industries because of their excellent wear and abrasion resistance. In this study, the effect of $TiO_2$ particles of composite coating was investigated. To improve the corrosion resistance, electroless $Ni-P-TiO_2$composite coating was studied by varying the $TiO_2$ content. The morphology and phase structure of $Ni-P-TiO_2$ composite coatings were analyzed by scanning electron microscopy(SEM), X-ray diffractometry(XRD) and X-ray photoelectron spectroscopy(XPS). The result showed that $Ni-P-TiO_2$composite coating is composed of Ni, P, Ti and O. It exhibits an amorphous structure, high hardness and good corrosion resistance to the substrate. $Ni-P-TiO_2$ composite coatings have higher open circuit potential than that of the substrate, which obtained at $TiO_2$ content of 5.0 g/L optimal integrated properties.