• Korean Journal of Materials Research
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• v.12 no.10
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• pp.825-830
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• 2002

The growth rate of solid grains in TiC-XC-2vol% and TiC-XC-30vo1% Ni cermets, where X=Zr, W or Mo, was fitted to an equation of the form $d^3$-$do^3$=Kt. The grain growth behavior during liquid phase sintering at 1673K decreased markedly with addition of $Mo_2$C or WC and increased with addition of ZrC. The contiguity ratio was greater in the alloys with smaller growth rate constant and decreased with increasing Ni content in the $TiC-Mo_2$C-Ni cermet. The grain growth mechanism could be explained by the effect of contiguous grain boundaries in restricting the overall grain growth.

• Journal of the Korean Magnetics Society
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• v.20 no.3
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• pp.83-88
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• 2010

We investigated the electronic structure and magnetism of the (3d, 4d)-Pd alloyed c($2{\times}2$) monolayer systems, by use of the FLAPW band method. For comparison, pure 3d- and 4d-transition metal monolayers are also considered. We found that the antiferromagnetic configuration of pure V monolayers is sustained in the V-Pd alloy system, while the Ti-Pd alloy system is changed to antiferromagnetic configuration from the ferromagnetic state in pure Ti monolayer. The 4d TM (Mo, Ru, Rh)-Pd monolayers are found to be stable in ferromagnetic configurations. The magnetic moments of Ru and Rh atoms in Ru-Pd and Rh-Pd systems are almost same with those of pure Ru and Rh monolayers, while the magnetic moment of Mo atom is increased to $2.98\;{\mu}_B$ in Mo-Pd alloyed system from the value of Mo monolayer, $0.02\;{\mu}_B$.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2000.11a
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• pp.10-11
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• 2000

• Korean Journal of Materials Research
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• v.4 no.6
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• pp.669-680
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• 1994

Oxidation behaviour of TiAl intermetallic compounds with the addition of Cr, V, Si, Mo, or Nb was investigated at 900~$1100^{\circ}C$ under the atmospheric environment. The reaction products were examined by XRD, SEM equipped with WDX. The weight gain by continuous oxidation increased with the addition of Cr or V, but there was less weight gain when Mo, Si or Nb was added individually. he oxidation rate of Cr- or V-added TiAl was always larger than that of TiAI. However, oxidation rate of Si-, Mo- or Nb-added TiAl was almost same or smaller than that of TiAI. Thus, it is concluded that the addition of Cr or V did not improve the oxidation resistance, whereas the addition of Si, Mo or Nb improved the oxidation resistance. Oxides formed on TiAl with Mo, Si, and Nb were found to be more protective, resulting from the decrease in diffusion rate of the alloying elements and oxygen. Nb strengthened the tendency to form $AI_{2}O_{3}$ in the early stage of oxidation, due to the continuous $AI_{2}O_{3}$ layer formation and dense $Tio_{2}+AI_{2}O_{3}$ layer. According to the Pt-marker test of TiAI- 5wt%Nb, oxygen diffused mainly inward while oxides were formed on the substrate surface. Upon thermal cyclic oxidation at $900^{\circ}C$, it is shown that the addition of Cr or Nb improved the adherence of oxide scale to the substrate.

• Journal of the Korean Society for Heat Treatment
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• v.30 no.2
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• pp.43-52
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• 2017

Heat treatment condition for dissolution of the M23C6 carbides in 2.25Cr-1Mo-V-Ti material for thermal power plant tube was investigated using a dilatometer method. 2.25Cr-1Mo-V-Ti material was heat-treated at $900{\sim}1,100^{\circ}C$ for 0, 10, 30 min to find the proper dissolution condition of M23C6 carbides. The phase identification and volume fraction of the carbide were measured by using OM, SEM, EBSD and TEM analysis. Optimal heat treatment condition of M23C6 carbide dissolution was selected by predicting dissolution temperature of carbide using Bs points appeared at dilatometer curve. Experimental results showed that the conditions of carbide dissolution was 900, 1,000, $1,100^{\circ}C$ for 30 min. Eventually, the optimal heat treatment condition for dissolution was 30 min at $1,000^{\circ}C$ considering the minimum coarsening of Austenite grain size.

• Korean Journal of Materials Research
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• v.10 no.5
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• pp.343-349
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• 2000

Fabrication of various carbide fibers from carbon fibers and elementary powders of Ti, Zr, Nb, Zi, W, B, and Mo by self-propagating high temperature synthesis was attempted. It was found the almost pure phase of TiC, ZrC, NbC, SiC, $B_4$C, and $Mo_2$C carbides were successfully produced. The three types of morphologies were ob-served, TiC, ZrC, NbC, and $B_4$C had a hollow-type fibrous shape. SiC had fiber shape consisting of smaller particles and fine whiskers. WC and $Mo_2$C had non-fibrous shapes. The reason for the different morphologies was explained. The formation mechanism of hollow fibers was suggested.

• Journal of Ocean Engineering and Technology
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• v.11 no.3
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• pp.48-55
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• 1997

The steel for automotive exhaust system needs a good corrosion resistance at the atmosphere of high temperature NaCl. Effect of the alloying elements Me, Ti, Nb on the NaCl induced hot corrosion behavior was investigated at the temperatures between 55$0^{\circ}C$ and 75$0^{\circ}C$ for 18Cr ferritic stainless steels. The weight loss by corrosion has increased linearly with corrosion cycle time, and the corrosion rate has accelerated at higher temperature. The alloying of Mo significantly improved corrosion resistance of the steel and the effect was more pronounced at higher temperature. The addition of alloying elements Ti, Nb have also shown improved corrosion resistance by formation of Ti(C,N) or Nb(C, N) precipitates.

• International Journal of Precision Engineering and Manufacturing
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• v.5 no.1
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• pp.19-26
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• 2004

The growth of solid particles in TiC-XC-2vo1.% and TiC-XC-30vo1.% Ni alloys, (where X=Zr, W or Mo) was fitted to the equation of the form $d^3$-${do}^3$=Kt during the liquid phase sintering at 1,673K. Also, the grain growth behavior decreased markedly with the addition of ${MO}_2$C or WC and increased with the addition of zrC. The contiguity was greater in the alloys with a smaller growth rate constant and especially, decreased by increasing the Ni content in the TiC-${MO}_2$C-Ni alloy. In addition, the effect of the addition of carbide on the grain growth of 2 vo1.% Ni alloys was found to be similar to that of 30vo1.% Ni alloys. Consequently, the grain growth mechanism cannot be explained by the usual solution / reprecipitation process, but can be explained in terms of a new growth velocity equation, which includes the effects of contiguous carbide grain boundaries in restricting the overall grain growth, as well as the area of the solid / liquid interface in the alloy.

• Journal of the Microelectronics and Packaging Society
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• v.3 no.1
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• pp.25-32
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• 1996

본 연구에서는 BaTiO3에 Sr과 Pb를 치환시켜TiO3 조성의 세라믹 유전체를 제조한 후 페로브스카이트형 Ba(Cu, Mo)O3를 저융점 flux 로 첨가하여 120$0^{\circ}C$ 이하의 여러온도에 서 소결을 행하였으며 flux 첨가량의 변화에 따른 소결거동 및 유전 특성의변화를 조사하였 다. 이러한 저온 소결용 유전체 세라믹스가 MLCC의 응용시 Pt-Pd계의합금을 내부전극으로 사용가능성을 검토하였다. Flux를 4mol%첨가한 TiO3-0.04Ba(Cu,Mo)O3 조성의 유전체는 120$0^{\circ}C$의 온도에서 2시간 소결했을 경우 소결밀도는 이론밀도의 95% 에 근접하였으며 이때 의 비유전율은 8000이상을 나타내었다. 이러한 소결 온도의 감소는 저융점인 ba(Cu,Mo)O3 계의 flux가 첨가되면서 비교적 낮은 온도에서 액상을 형성하여 소결을 촉진시켰기 때문으 로 사료된다.

• Biomaterials and Biomechanics in Bioengineering
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• v.1 no.1
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• pp.51-62
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• 2014

The purpose of this experiment was to evaluate the apatite-formation abilities of low-modulus Ti-7.5Mo substrates treated with NaOH aqueous solutions and subsequent ethyl alcohol aging before soaking them in simulated body fluid. Specimens of Ti-7.5Mo were initially treated with 5 M NaOH at $60^{\circ}C$ for 24 h, resulting in the formation of a porous network structure composed of sodium hydrogen titanate. Afterwards, the specimens were aged in ethyl alcohol at $60^{\circ}C$ for 5 or 10 min, and subsequently immersed in simulated body fluid at $37^{\circ}C$ for 3, 7 and 14 days. Ethyl alcohol aging significantly increased the apatite-forming abilities of Ti-7.5Mo. The amount of apatite deposited on the Ti-7.5Mo after NaOH treatment and subsequent ethyl alcohol aging was much greater, especially after the Ti-7.5Mo specimens were aged for 5 min. Due to its excellent combination of bioactivity, low elastic modulus and low processing costs, the Ti-7.5Mo treated with NaOH aqueous solutions and subsequently aged in ethyl alcohol has promising heavy load-bearing applications.