• Journal of the Korean institute of surface engineering
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• v.35 no.6
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• pp.391-400
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• 2002

Corrosion characteristics of Ti, Ti/Cr coated and plasma-nitrided surface for stainless steel containing Ti have been studied. Stainless steels containing 0.09-0.92wt% Ti were fabricated by using vacuum furnace and solutionized for 1hr at 105$0^{\circ}C$. Ti and Cr coatings were done on solutionized stainless steel surface by EB-PVD. The Ti coated specimen were coated by Cr and were nitrided by plasma at $450^{\circ}C$ for 5hr. Microstructure and phase analysis were performed using SEM, OM and EDX. Corrosion behavior of the coated specimen was investigated by electrochemical test. The coated surface was of fine columnar structure. The Ti/Cr coated surface was denser than the Ti coated and the Ti coated-nitrided surfaces. The corrosion and pitting potential increased in proportion to the Ti content, coating temperature, coating thickness and formation of stable oxide film. The current density in active and passive region decreased in the case of Ti/Cr coated sample and Ti coated-nitrided samples. Especially the plasma nitrided specimen after Ti coating have a good corrosion resistance compared with the Ti coated specimen. The number and size of pits decreased as Ti content of matrix increased.

• Journal of the Korean institute of surface engineering
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• v.36 no.1
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• pp.89-98
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• 2003

Corrosion characteristics of Ti, Ti/Cr coated and plasma-nitrided surface for stainless steel containing Ti have been studied. Stainless steels containing 0.09-0.92wt% Ti were fabricated by using vacuum furnace and solutionized for 1hr at $1050^{\circ}C$. Ti and Cr coatings were done on solutionized stainless steel surface by EB-PVD. The Ti coated specimen were coated by Cr and were nitrided by plasma at $450^{\circ}C$ for 5hr Microstructure and phase analysis were performed using SEM, OM and EDX. Corrosion behavior of the coated specimen was investigated by electrochemical test. The coated surface was of fine columnar structure. The Ti/Cr coated surface was denser than the Ti coated and the Ti coated-nitrided surfaces. The corrosion and pitting potential increased in proportion to the Ti content, coating temperature, coating thickness and formation of stable oxide film. The current density in active and passive region decreased in the case of Ti/Cr coated sample and Ti coated-nitrided samples. Especially the plasma nitrided specimen after Ti coating have a good corrosion resistance compared with the Ti coated specimen. The number and size of pits decreased as Ti content of matrix increased.

• Journal of the Korean Society for Heat Treatment
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• v.14 no.6
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• pp.330-335
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• 2001

Flake graphite cast irons with the high damping capacity have been used for the control of vibration and noise occurring in the members of various mechanical structures under vibrating conditions. However, the damping capacity which Is morphological characteristics of graphite is one of the important factors in reducing the vibration and noise, but hardly any work has deal with this problem. Therefore, the authors have examined the damping capacity of various cast irons with alloying elements and studied the influences of the matrix structures, mechanical properties and morphological characteristics of graphite. The main results obtained are as follows: Effects of Sb on the damping capacities and mechanical properties have been investigated in 3.6%C-0.2%Ni gray cast iron. At 0.02%Sb, specific damping capacity showed the maximum value, and decreased with further increase in Sb content. Mechanical properties showed opposite trend with the damping capacity. And then, effects of Ti on the damping capacities and mechanical properties have been investigated in 3.6%C-0.2%Ni-0.02%Sb gray cast iron. Specific damping capacity increased with increase in Ti content. Graphite length also showed same behavior. Tensile strength increased with Ti content due to refinement of pearlite. In the case of 0.14%Ti addition in 3.6%C-0.2%Ni-0.02%Sb cast iron, specific damping capacity and tensile strength was 36% and 25 $kgf/mm^2$ which are higher than 32% and 15 $kgf/mm^2$ at 3.6%C-0.2%Ni cast iron respectively.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.272-278
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• 1999

Tungsten Carbide(WC) Roll is widely used in finishing stands of wire rod mill. This report is about the manufacturing method of WC roll with excellent wear resistance. To enhance wear resistance, WC content has been increased to the maximum extent while binder content such as Co, Ni, Cr has been minimized. Part of WC is replaced with TiC having more wear resistant than WC. WTiC powder has been used to prevent weight unbalance resulting from the difference of specific weight when adding TiC. The roll manufactured by this method, is having more wear resistance than the existing rolls when applying to the final stand of the finishing mill. This report shows that WC is the critical factor of wear resistance in WC rolls and an approprite amount of TiC effects wear resistance and when adding TiC, using WTiC powder is better.

• Journal of Korea Foundry Society
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• v.29 no.2
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• pp.59-63
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• 2009

Effects of Ti on damping capacity and mechanical properties are investigated in hot rolled Fe-17%Mn alloy. The existing damping alloy with Fe-Mn binary system was limited the use by high production cost, however in case of using scrap iron instead of pure iron although the content of carbon is higher it is possible to be applied wider field especially construction items because the production cost is lower. However, the excellent specific damping capacity is dropped due to the high content of carbon, we developed advanced type of damping alloy included Ti. TiC is formed with added Ti and it holds the specific damping capacity similar to existing damping alloy. The effect of Ti on damping capacity is found to be beneficial in carbon-containing alloy, which is attributed to the depletion of carbon solute due to the formation of TiC.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.355-356
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• 2006

WC-TiC-TaC binderless cemented carbide was oxidized under low partial pressure of oxygen (50ppm) at 873K for 1 to 20 h. Surface roughness was measured using atomic force microscope, and effect of TiC amount on oxidation behavior of the carbide was investigated. WC phase was oxidized more easily than WC-TiC-TaC solid solution phase. With an increase in TiC amount, WC-TiC-TaC phase increased and the oxidation resistance of the carbide increased.

• Analytical Science and Technology
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• v.21 no.3
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• pp.229-236
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• 2008

$C/TiO_2$ composites were prepared with surface modified MWCNT sequentially after HCl treatment and TNB as titanium source. There is a single crystal structure which is anatase in all of the samples from the data of XRD. The SEM microphotographs of $C/TiO_2$ composites show that the $TiO_2$ particles were well mixed with the CNT. There are C, O and Al with strong Ti peaks in all samples from EDX results, and it also shows that the sample CT has much more amount of C and Ti content than that of sample HCT. Finally, the photocatalytic activities for the $C/TiO_2$ composites have more effective than that of pristine $TiO_2$.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.239-245
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• 2000

Sintered $Al_2TiO_5$ has a very low thermal expansion and an infrared radiative selectively emitting large amounts of far infrared rays. However, it is week in mechanical strength. Spectral infrared emittance, thermal expansion coefficient, and mechanical strength of $Al_2TiO_5$-clay composites were studied to develop a material for far infrared radiators. The composites containing 10~50 mass% Jungsan clay had high emittance in the range of 2,000~500cm-1. The bending strength of the $Al_2TiO_5$-clay composites increased with increasing clay content. The $Al_2TiO_5$-clay composites with a clay content of 50mass% and heat-treated at $1,200^{\circ}C$ had a large strength for infrared radiators ; 86MPa. The average linear thermal expansion coefficient from $200{\sim}1,000^{\circ}C$ of the 50mass% jungsan clay containing compo sited heat-treated at $1,200^{\circ}C$ was lower than $3.87{\times}10-6/^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.91-92
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• 2007

An anomalous positive temperature coefficient of electrical resistivity (PTCR) was investigated in a ferroelectric lead-free perovskite-type compound $(Bi_{0.5}Na_{0.5})TiO_3$ within $BaTiO_3$-based solid solution ceramics. The effect of $Nb_2O_5$ content on the electrical properties and the microstructure of (1 - x) $BaTiO_3-x\;(Bi_{0.5}Na_{0.5})TiO_3$ (BNT) ceramics made using a conventional mixed oxide process also has been studied. The Curie temperature was obviously increased with the increasing of $(Bi_{0.5}Na_{0.5})TIO_3$ content. The Nb - doped BNT ceramics (x=0.01) display low resistivity values of $10^{1{\circ}}C-10^{2{\circ}}C$ ohm.cm at room temperature and the Curie Temperature of $T_c=160^{\circ}C$.

• Journal of the Korean institute of surface engineering
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• v.33 no.2
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• pp.93-100
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• 2000

Effects of Ti content and Ti underlayer on the pitting behavior of TiN coated AISI 304 stainless steel have been studied. The stainless steel containing 0.1~1.0wt% Ti were melted with a vacuum melting furnace and heat treated at $1050^{\circ}C$ for 1hr for solutionization. The specimen were coated with l$\mu\textrm{m}$ and 2$\mu\textrm{m}$ thickness of Ti and TiN by E-beam PVD method. The microstructure and phase analysis were conducted by using XRD, XPS and SEM with these specimen. XRD patterns shows that in TiN single-layer only the TiN (111) Peak is major and the other peaks are very weak, but in Ti/TiN double-layer TiN (220) and TiN (200) peaks are developed. It is observed that the surface of coating is covered with titanium oxide (TiO$_2$) and titanium oxynitride ($TiO_2$N) as well as TiN. Corrosion potential on the anodic polarization curve measured in HCl solution increase in proportion to the Ti content of substrate and by a presence of the Ti underlayer, whereas corrosion and passivation current densities are not affected by either of them. The number and size of pits decrease with increasing Ti content and a presence of the coated Ti film as underlayer in the TiN coated stainless steel.