• 한국주조공학회지
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• 제18권5호
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• pp.488-493
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• 1998

Commercially pure titanium(cp-Ti) and Ti-15wt%Zr-4wt%Nb-4wt%Ta alloy were melted in vacuum induction furnace. According to the chemical analysis, the content of carbon was above ASTM standard in the cast ingots because of using graphite crucible. The TEM micostructures of cp-Ti and Ti alloy shows that chemically stable TiC precipitates distribute in ${\alpha}-Ti$ matrix. In order to examine the properties of cp-Ti and Ti-Zr-Nb-Ta alloy for dental applications, mechanical properties and corrosion resistance were investigated. The anodic polarization properties of Ti-Zr-Nb-Zr alloy were almost same as that of cp-Ti in 1% lactic acid. However, as the results of the anodic polarization test in 5% HCl, it was known that Ti-Zr-Nb-Zr alloy showed a rapid decrease in current density at higher potential in comparison with cp-Ti. The yield stress and tensile strengh in Ti-Zr-Nb-Ta were ${\sigma}_{0.2}=623\;MPa$, ${\sigma}_{T.S.}=708\;MPa$ and these results showed 30% increase in yield stress in comparison with cp-Ti.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1994년도 특별강연 및 추계학술발표 개요집
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• pp.166-168
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• 1994

• 한국재료학회지
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• 제15권9호
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• pp.585-588
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• 2005

Titanium and Titanium alloys are widely used as an orthopedic and dental implant material because of their excellent biocompatibility and mechanical strength. In this study, ECAP Cp-Ti and Cp-Ti were heat treated for different annealing time of 30 min, 90 min and 3 hours. The grain size for each condition was studied. The micro-Vicker hardness test was carried out f3r each different heat treated samples. The micro-Vicker hardness test for ECAP Cp-Ti, Cp-Ti and Cp-Ti (3hr) revealed hardness values of 239.5, 182 and 144 Hv, respectively. The grain size was increased from approximately $70{\mu}m\;to\;300{\mu}m$ with the increase in heat treatment time from 30 min to 3 hours. The heat treated samples were tested for their biocompatibility in simulated body fluid (SBF) and corrosion rates was determined using Polarization Curve test (PCT). The PCT results showed Cp-Ti with comparatively high corrosion potential of -0.18 V and corresponding corrosion current of $2\times10^{-6}$ A, while the corrosion rate in ECAP Cp-Ti and Cp-Ti (30 min annealed) showed very similar results of corrosion potential about -0.47 V with corresponding corrosion current of $7\times10^{-8}$ A.

• 대한치과기공학회지
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• 제30권1호
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• pp.25-31
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• 2008

Cp-Ti and Ti-6Al-4V alloys commonly used dental implant materials, particularly for orthopaedic and osteosynthesis because of its suitable mechanical properties and excellent biocompatibility. This alloys have excellent corrosion behavior in the clinical environment. The first factor to decide the success of dental implantation is sufficient osseointegration and high corrosion resistance between on implant fixture and its surrounding bone tissue. In this study, in order to increase corrosion resistance and biocompatibility of Cp-Ti and Ti-6Al-4V alloy that surface of manufactured alloy was coated with TiN by RF-magnetron sputtering method. The electrochemical behavior of TiN coated Cp-Ti and Ti-6Al-4V alloy were investigated using potentiodynamic (EG&G Co, PARSTAT 2273. USA) and potentiostatic test (250mV) in 0.9% NaCl solution at 36.5 $\pm$ 1$^{\circ}C$. These results are as follows : 1. From the microstructure analysis, Cp-Ti showed the acicular structure of $\alpha$-phase and Ti-6Al-4V showed the micro-acicular structure of ${\alpha}+{\beta}$ phase. 2. From the potentiodynamic test, Ecorr value of Cp-Ti and Ti-6Al-4V alloys showed -702.48mV and -319.87mV, respectively. Ti-6Al-4V alloy value was higher than Cp-Ti alloy. 3. From the analysis of TiN and coated layer, TIN coated surface showed columnar structure with 800 nm thickness. 4. The corrosion resistance of TiN coated Cp-Ti and Ti-6Al-4V alloys were higher than those of the non-coated Ti alloys in 0.9% NaCl solution from potentiodynamic test, indicating better protective effect. 5. The passivation current density of TiN coated Cp-Ti and Ti-6Al-4V alloys were smaller than that of the noncoated implant fixture in 0.9% NaCl solution, indicating the good protective effect resulting from more compact and homogeneous layer formation.

• 한국주조공학회지
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• 제15권4호
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• pp.368-376
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• 1995

An Al-composite material was fabricated with using the rheocompocasting process and the microstructure of the Al-Cu/SiCp composite material was investigated depending on the stirring times and the amount of Ti additions. The distribution of SiC dispersion shows the good result at the stirring time of 30 min. The degree of microdistribution of the $Al_2Cu$ and SiCp is improved when the amount of Ti addition is increased. At the compositon of 0.3%Ti, the primary solid is the compound of $Al_3Ti$ and no exist of the SiCp and $Al_2Cu$ phase around the primary $Al_3Ti$. In the process of compositization, SiCp is found at the primary and final solid parts and is found at the final solid part after remelting. $Al_2Cu$ and SiCp are distributed around and outside of dendrite or independently after remelting, which is different from the process of compositization.

• 한국재료학회지
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• 제15권7호
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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.

• 대한화학회지
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• 제38권1호
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• pp.55-60
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• 1994

유기규소 중합반응에서 나타나는 중간체 $Cp_2TiSiHPh(1),\;[Cp_2Ti]_2[{\mu}-HSi(HPh)][{\mu}-H]$ (2) 그리고 $[Cp_2TiSiH_2Ph]_2$ (3)화합물들의 전자구조를 EHT방법으로 연구하였다. 1 화합물의 안정한 구조는 Cs로 변형된 형태이고 $SiH_2$의 회전에너지는 약 14 kcal/mol로 나타났다. 전자결핍분자인 2와 3 화합물의 결합특성을 전자구조를 통하여 규명하였다. 또한 Ti금속이 Si-H의 $\sigma$ 결합과 작용할 가능성을 설명하였다.

• 대한의용생체공학회:의공학회지
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• 제25권5호
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• pp.383-389
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• 2004

본 연구에서는 치과용 티타늄(CP-Ti)과 Ti-25wt%Pd를 인산염계 실리카$.$알루미나 주형재로 주조 후 SEM/EDS, XRD, XPS를 이용하여 주조시 생성되는 표면반응생성물을 조사하였다. Ti-25wt%Pd는 CP-Ti에 비하여 융점이 현저이 감소하여 주조체의 표면반응이 상대적으로 적게 발생하였다. 또한 인산염계 실리카$.$알루미나 주형재를 소성한 결과 주형재는 $SiO_2$, $Al_2$ $O_3$, P$_2$ $O_{5}$, $Mg_3$(P $O_4$)$_2$, AlP $O_4$, $Mg_2$ $SiO_4$, MgAl$_2$ $O_4$의 성분들로 구성되어 있었으며, 표면반응생성물은 CP-Ti 주조체의 경우 $Ti_{5}$Si$_3$ 와 Ti $O_2$로, Ti-25wt%Pd 주조체의 경우 Ti $O_2$ 와 $SiO_{x}$ 로 구성되어 있었다.

• 대한치과기공학회지
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• 제31권4호
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• pp.31-36
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• 2009

This study evaluated the grindability of series of Ti-Cu alloys in order to develop a Ti alloy with better grindability than commercially pure titanium(CP Ti). Experimental Ti-Xwt%Cu alloys(X=2, 5, 10) were made in an argon-arc melting furnace. Slabs of experimental alloys were ground using a SiC abrasive wheel on an electric handpiece at circumferential speed(15000, 30000rpm) by applying a force(250, 300gr). Grindability was evaluated by measuring the amount of metal volume removed after grinding for 2 minutes. Data were compared to those for CP Ti and Ti-6wt%Al-4wt%V alloy. From results, It was observed that the grindability of Ti-Cu alloys increased with an increase in the Cu concentration compared to CP Ti, particularly the 10wt%Cu alloy exhibited the highest grindability at all speeds. By alloying with Cu, the Ti exhibited better grindability at high speed. The continuous precipitation of $Ti_2Cu$ among the ${\alpha}$-matrix grains made this material less ductile and facilitated more effective grinding because small segments more readily formed. The Ti-10wt%Cu alloy has a great potential for use as a dental machining alloy.

• 한국재료학회지
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• 제14권12호
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• pp.893-899
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• 2004

Even though Ti-6Al-4V has gained popularity as an implant material, the possible dissolution of Al and V ions in body fluids remains a matter of concern. Though commercially pure Ti (Cp-Ti) overcomes this problem, the mechanical strength of pure titanium remains very low. Thus, in this experiment Cp-Ti was processed by Equal channel angular processing (ECAP), in order to increase the mechanical strength. The biocompatibility of ECAP-Ti, Cp-Ti and Ti-6Al-4V was examined by the apatite formation on each sample surface, after treating the surface with 5M NaOH and soaking in Simulated body fluids (SBF). Initially, the samples were mechanically polished on silicone carbide paper (#2000). The polished samples were treated with 5M NaOH solution at $60^{\circ}C$ for 24 hours. The NaOH treated samples were washed gently with distill water and dried at $40^{\circ}C$ for 1 day. The dried samples were heat treated in air at $600^{\circ}C$ for 1 hour. The surface morphology of these samples were studied using SEM and XRD. The SEM studies showed network of pores in all samples. The XRD showed oxide layer formation on Cp-Ti and Ti-6Al-4V. samples. However the oxide layer in ECAP-Ti was not substantial. These samples were immersed in SBF, kept at $36.5^{\circ}C$ for seven days period. At the end of 7 days, the apatite formation was confirmed only on Cp-Ti and was not observed in Ti-6Al-4V and ECAP-Ti. These observations of apatite formation relate to the fact that Cp-Ti showed greater oxide layer than other samples. The apatite examined was confirmed as tricalcium phosphate (TCP) using EDS and XRD.