• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1114-1118
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• 2000

Ti 및 C 입자로 이루어진 다공질 성형체에 용융 Si의 침윤 및 반응으로 새로운 Ti$_3$SiC$_2$합성공정이 개발되었다. 용융 Si 침윤에 의한 Ti$_3$SiC$_2$합성공정에서는 이제까지 연구된 합성방법 보다 넓은 조성 범위에서 Ti$_3$SiC$_2$의 합성이 이루어졌다. 용융 Si을 활성 매질로 사용한 Ti$_3$SiC$_2$의 합성에서는 성형체 조성, 원료 입자 크기 및 침윤되는 용융 Si의 양에 따라 합성되는 상 및 각 합성상의 양이 다르게 나타났다. Ti:Si:C=3:1:6 조성을 제외한 모든 조성의 시편에서 Ti$_3$SiC$_2$상이 합성되었으며, 일부 조성을 제외한 모든 조성의 시편에서 Ti$_3$SiC$_2$, TiC 및 SiC가 함께 합성되었다. 작은 Ti 입자로 이루어진 성형체를 사용하여 합성한 시편에서 Ti$_3$SiC$_2$상의 합성이 용이하게 이루어졌으며, 성형체 조성 및 침윤되는 Si의 양이 화학양론적으로 Ti$_3$SiC$_2$에 근접한 조성을 갖는 시편에서 Ti$_3$SiC$_2$를 높은 수율로 합성할 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.396-400
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• 2003

A new synthesis process for nano laminating Ti$_3$SiC$_2$ has been developed using TiCx (x=0.67) and Si powder as starting materials by a reaction hot pressing. Bulk Ti$_3$SiC$_2$ was fabricated using a green body consisting of TiCx and Si by a hot pressing under the pressures of 25 MPa at 1420-1550 $^{\circ}C$ for 90 min. The synthesized Ti$_3$SiC$_2$ was consisting of only TiCx and Ti$_3$SiC$_2$. The relative density of sintered bulk Ti$_3$SiC$_2$ was increased as the hot pressing temperature was increased, which was mainly due to the increase in TiCx contents in synthesized Ti$_3$SiC$_2$. The synthesized Ti$_3$SiC$_2$ bulk was consisted of nano sized lamella structure of 20-100 nm in thickness. It was found that TiCx particles in Ti$_3$SiC$_2$ would increase the 3-point bending strength of synthesized Ti$_3$SiC$_2$ bulk. The maximum 3-P. bending strength of synthesized Ti$_3$SiC$_2$ bulk was more than 800 MPa. The Vickers hardness of synthesized Ti$_3$SiC$_2$bulk was as low as 5 Gpa, which was decreased with the indentation load. The quasi-plastic deformation behaviors were observed around indentation mark on Ti$_3$SiC$_2$.

• Journal of the Korean Ceramic Society
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• v.35 no.8
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• pp.807-812
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• 1998

Mechanical properties of two types of polycrystlline {{{{ { { Ti}_{3 }SiC }_{2 } }} with different grain size were investigated. A fine grain {{{{ { { Ti}_{3 }SiC }_{2 } }} has a higher fracture strength and hardness. Plot of strength versus Vickers indentation load indicated that {{{{ { { Ti}_{3 }SiC }_{2 } }} has a high flaw tolerance. Hertzian indentation test using a spherical indenter was used to study elastic and plastic behavior in {{{{ { { Ti}_{3 }SiC }_{2 } }}. Indentation stress-strain curves of each material are made to evaluate the plasticity of {{{{ { { Ti}_{3 }SiC }_{2 } }} Both find and coarse grain {{{{ { { Ti}_{3 }SiC }_{2 } }} showed high plasticity. In-dentation stress-strain curve of coarse grain {{{{ { { Ti}_{3 }SiC }_{2 } }} deviated even more from an ideal elastic limit in-dicating exceptional plasticity in this material. Deformation zones were formed below the contact as well as around the contact area in both materials but the size of deformation zone in coarse grain {{{{ { { Ti}_{3 }SiC }_{2 } }} was much larger than that in fine grain {{{{ { { Ti}_{3 }SiC }_{2 } }} Intragrain slip and kink would account for high plasticity. Plastic behavior of {{{{ { { Ti}_{3 }SiC }_{2 } }} was strongly influenced by grain size.

• Journal of the Korean Ceramic Society
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• v.39 no.4
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• pp.413-419
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• 2002

Particulate composites of $Al_2O_3$/TiC/SiC, $Al_2O_3$/TiC and $Al_2O_3$/SiC have been fabricated by hot pressing and their R-curve behaviors and mechanical properties were investigated. $Al_2O_3$ containing 30 vol% TiC particles showed higher toughness by 8% than that for monolithic alumina and its fracture strength was increased significantly by approximately 30%. On the other hand, the addition of 30 vol% SiC of $3{\mu}m$ in $Al_2O_3$ decreased the fracture strength slightly but induced a rising R-curve behavior owing to the strong crack bridging of SiC particles. In case of $Al_2O_3$/TiC/SiC, arising R-curve behavior was also observed and the fracture toughness reached 6.6 MPa${\cdot}\sqrt{m}$ at the crack length of $1000{\mu}m$, which was lower than that of $Al_2O_3$/SiC, however, while the fracture strength was higher by about 20%. The fracture toughness seemed to be decreased as smaller TiC particles roughened the SiC interface and pullout of the SiC particles for crack bridging became less active.

• Journal of Powder Materials
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• v.6 no.1
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• pp.18-35
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• 1999

Phase equilibria in the system Si3N4-TiC-TiCxN1-x-C-N were determined by thermodynamic calculations (CALPHAD-method). The reaction peaction paths for Si3N4-TiC and SiC-TiC composites in the Ti-Si-C-n system were simulated at I bar N2-pressure and varying terpreatures. At a temperature of 1923 K two tie-triangles (TiC0.34N0.66+SiC+C and TiC0.13N0.87+SiC+Si3N4) and two 2-phase fieds (TiCxN1-x+SiC; 0.13

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.560-565
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• 2010

Nano laminated bulk $Ti_3SiC_2$ was synthesized by hot press process using TiCx/Si powder mixture at the temperature range of $1300^{\circ}C\sim1500^{\circ}C$. pure $Ti_3SiC_2$ was synthesized by a hot pressing above $1400^{\circ}C$, while unreacted TiCx were remained in bulk $Ti_3SiC_2$ which synthesized below $1400^{\circ}C$. The sintering density of bulk $Ti_3SiC_2$ were varied with the amount of TiCx. It was found that the mechanical properties and micro structures of bulk $Ti_3SiC_2$ were closely related to the amounts of TiCx which was controlled by the hot pressing temperature. The TiCx increase the flexural strength of bulk $Ti_3SiC_2$, while the fracture toughness and thermal shock resistance of bulk $Ti_3SiC_2$ were decreased with the content of TiCx. The plastic deformations of bulk $Ti_3SiC_2$ were appeared above $1000^{\circ}C$.

• Korean Journal of Materials Research
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• v.12 no.1
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• pp.48-53
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• 2002

$Al_2O_3-SiC$ and $Al_2O_3-SiC$-TiC composite powders were prepared by SHS process using $SiO_2,\;TiO_2$, Al and C as raw materials. Aluminum powder was used as reducing agent of $SiO_2,\;TiO_2$ and activated charcoal was used as carbon source. In the preparations of $Al_2O_3-SiC$, the effect of the molar ratio in raw materials, compaction pressure, preheating temperature and atmosphere were investigated. The most important variable affecting the synthesis of $Al_2O_3-SiC$ was the molar ratio of carbon. Unreactants remained in the product among all conditions without compaction. The optimum condition in this reaction was $SiO_2$: Al: C=3: 5: 5.5, 80MPa compaction pressure under Preheating of $400^{\circ}C$ with Ar atmosphere. However there remains cabon in the optimum condition. The effect of $TiO_2$ as additive was investigated in the preparations of $Al_2O_3-SiC$. As a result of $TiO_2$ addition, $Al_2O_3-SiC$-TiC composite powder was prepared. The $Al_2O_3$ powder showed an angular type with 8 to $15{\mu}m$, and the particle size of SiC powder were 5~$10{\mu}m$ and TiC powder were 2 to $5{\mu}m$.

• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.87-92
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• 2016

Due to its stability at high temperature and its layered structure, $Ti_3SiC_2$ MAX phase was considered to the interphase of $SiC_f/SiC$ composite. In this study, $Ti_3SiC_2$ MAX phase powder was deposited on SiC fiber via the electrophoretic deposition (EPD) method. The Zeta potential of the $Ti_3SiC_2$ suspension with and without polyethyleneimine as a dispersant was measured to determine the conditions of the EPD experiments. Using a suspension with 0.03 wt.% ball milled $Ti_3SiC_2$ powder and 0.3 wt.% PEI, $Ti_3SiC_2$ MAX phase was successfully coated on SiC fiber with an EPD voltage of 10 V for 2 h. Most of the coated $Ti_3SiC_2$ powders are composed of spherical particles. Part of the $Ti_3SiC_2$ powders that are platelet shaped are oriented parallel to the SiC fiber surface. From these results we expect that $Ti_3SiC_2$ can be applied to the interphase of $SiC_f/SiC$ composites.

• Journal of the Korean Ceramic Society
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• v.54 no.4
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• pp.340-348
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• 2017

$SiC_f/SiC$ composites were joined using a $60{\mu}m-thick$ $Ti_3AlC_2$ or $Ti_3SiC_2$ MAX phase tape. The filler tape was inserted between the $SiC_f/SiC$ composites containing a 12 wt.% $Al_2O_3-Y_2O_3$ sintering additive. The joining was performed to a butt-joint configuration at $1600^{\circ}C$ or $1750^{\circ}C$ in an Ar atmosphere by applying 3.5 MPa using a hot press. Microstructural and phase analyses at the joining interface confirmed the decomposition of $Ti_3AlC_2$ and $Ti_3SiC_2$, indicating the joining by solid-state diffusion. The results showed sound joining interface without the presence of cracks. Joining strengths higher than 150 MPa could be obtained for the joints using $Ti_3AlC_2$ or $Ti_3SiC_2$ at $1750^{\circ}C$, while those for joined at $1600^{\circ}C$ decreased to 100 MPa approximately without the deformation of the joining bodies. The thickness of initial filler tape was reduced significantly after joining because of the decomposition and migration of MAX phase owing to the plasticity at high temperatures.

• Journal of the Korean institute of surface engineering
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• v.37 no.6
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• pp.360-365
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• 2004

Ti$_3$SiC$_2$ material was synthesized via the powder metallurgical route, and oxidation tested between 900 and $1200^{\circ}C$ in air for up to 100 hr. The oxidation of $Ti_3$$SiC_2$ material resulted in the formation of $TiO_2$and $SiO_2$, accompanying the evolution of CO or $CO_2$ gases from the initial stage of oxidation. The oxidation resistance of $Ti_3$$SiC_2$ mainly owes the protectiveness of highly stoichiometric $SiO_2$. During the initial stage of oxidation, the dominant reaction was the inward transport of oxygen into the matrix. As the oxidation progressed, an outer $TiO_2$ layer and an inner ( $TiO_2$ + $SiO_2$) mixed layer formed. Between these layers and inside the oxide scale, numerous fine voids formed. Numerous, fine oxide grains formed at $900^{\circ}C$ developed into the outer coarse $TiO_2$ grains and an inner fine ($TiO_2$ + $SiO_2$) mixed grains at the higher temperatures. The oxidation resistance of$ Ti_3$SiC$_2$ progressively deteriorated as the oxidation temperature increased, forming thick scales above $1000^{\circ}C$. The outer coarse $TiO_2$ grains formed above $1100^{\circ}C$ grew rapidly mainly along (211).