• 제목/요약/키워드: Electroconductive composites

검색결과 51건 처리시간 0.034초

액상소결에 의한 $\beta-SiC-ZrB_2$ 복합체의 제조와 특성(II) (Properties and Manufacture of $\beta-SiC-ZrB_2$ Composites Densified by Liquid-Phase Sintering(II))

  • 윤세원;황철;주진영;신용덕
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제49권2호
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    • pp.92-97
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    • 2000
  • The mechanical and electrical properties of the hot-pressed and annealed $\beta$-SiC+39vol. %ZrB2 electroconductive ceramic composites were investigated by adding 1, 2, 3wt% Al2O3+Y2O3(6:4wt%) of the liquid forming additives. In this microstructures, no reactions were observed between $\beta-SiC$ and ZrB2. The relative density is over 90.8% of the theoretical density and the porosity decreased with increasing Al2O3+Y2O3 contents. Phase analysis of the composites by XRD revealed $\alpha-SiC(6H, 4H)$, ZrB2 and $\beta-SiC$(15R). Flexural srength showed the highest of 315.5MPa for composites added with 3wt% Al2O3+Y2O3 additives as room temperature. Owing to crack deflection and crack bridging of fracture toughness mechanism, the fracture toughness showed 5.5MPa.m1/2 and 5.3MPa.m1/2 for composites added with 2wt% and 3wt% Al2O3+Y2O3 additives respectively at room temperature. The area fraction of the elongated SiC grain in the etched surface of sample showed 65% and 65.1% for composite added with 2wt% and 3wt% Al2O3+Y2O3 additives respectively. The electrical resistivity at room temperature. The electrical resistivity of the composites wall all positive temperature coefficient(PTCR) against temperature up to $700^{\circ}C$.

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$\beta$-Sic-$TiB_2$복합체의 파괴인성과 전기전도도젠 미치는 YAG의 영향 (Effect of the YAG with fracture toughness and electric conductive of $\beta$-Sic-$TiB_2$)

  • 윤세원;주진영;신용덕;여동훈;박기엽
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 C
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    • pp.1545-1547
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    • 2000
  • The mechanical and electrical properties of the hot-pressed and annealed $\beta$-Sic-$TiB_2$ electroconductive ceramic composites were investigated as function of the liquid forming additives of $Al_{2}O_{3}+Y_{2}O_3$. Phase analysis of composites by XRD revealed $\alpha$-SiC(6H), $TiB_2$, and YAG($Al_{5}Y_{3}O_{12}$). The relative density and the mechanical properties of composites were increased with increasing $Al_{2}O_{3}+Y_{2}O_3$ contents because YAG of reaction between $Al_{2}O_3$ and $Y_{2}O_3$ was increased. The Flexural strength showed the highest value of 432.5MPa for composites added with l2wt% $Al_{2}O_{3}+Y_{2}O_3$ additives at room temperature. Owing to crack deflection, crack bridging, phase transition and YAG of fracture toughness mechanism. the fracture toughness showed 7.1MPa${\cdot}m^{1/2}$. For composites added with l2wt% $Al_{2}O_{3}+Y_{2}O_3$ additives at room temperature The electrical resistivity and the resistance temperature coefficient respectively showed the lowest of 6.0${\sim}10^{-4}{\Omega}{\cdot}$ cm and 3.1${\times}10^{-3}/^{\circ}C$ for composite added with l2wt% $Al_{2}O_{3}+Y_{2}O_3$ additives at room temperature. The electrical resistivity of the composites was all positive temperature coefficient resistance(PTCR) in the temperature range of 25$^{\circ}C$ to 700$^{\circ}C$.

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無加壓 열처리에 의한 ${\beta}$-SIC-TiB$_2$ 複合體의 製造와 特性 (Manufacture and Properties of ${\beta}$-SIC-TiB$_2$ Composites Densified by Pressureless Annealing)

  • 신용덕;주진영;박미림
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제50권5호
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    • pp.221-225
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    • 2001
  • The effect of $Al_2O_3+Y_2O_3$ additives on fracture toughness of ${\beta}-SiC-TiB_2$ composites by hot-pressed sintering was investigated. The ${\beta}-SiC-TiB_2$ ceramic composites were hot-press sintered and pressureless-annealed by adding 16, 20, 24 wt% ${\beta}-SiC-TiB_2$(6:4 wt%) powder as a liquid forming additives at low temperature(1800 $^{\circ}C$) for 4 h. Phase analysis of composites by XRD revealed mostly of ${\alpha}$-SiC(6H), $TiB_2$, and YAG($Al_5Y_3O_{12}$). The relative density was over 95-88 % of the theoretical density, and the porosity increased with increasing $Al_2O_3+Y_2O_3$ contents because of the increasing tendency of pore formation. The fracture toughness showed the highest value of 5.88 MPa${\cdot}m^{1/2}$ for composites added with 20 wt% $Al_2O_3+Y_2O_3$ additives at room temperature. The electrical resistivity showed the lowest value of $5.22{\times}10^{-4}\;{\Omega}\;{\cdot}\;cm$ for composite added with 20 wt% $Al_2O_3+Y_2O_3$ additives at room temperature, and was all positive temperature coefficeint resistance(PTCR) against temperature up to 900 $^{\circ}C$.

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Annealing에 따른 $\beta$-SiC-$TiB_2$ 복합체의 특성 (Properties of $\beta$-SiC-$TiB_2$ Composites by Annealing)

  • 임승혁;송준태;박미림;주진영;신용덕
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 C
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    • pp.1634-1636
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    • 2000
  • The mechanical and electrical properties of the hot-pressed and annealed $\beta$-SiC-$TiB_2$ electroconductive ceramic composites were investigated as function of the liquid forming additives of $Al_{2}O_{3}+Y_{2}O_3$ and the annealing method. Phase analysis of composites by XRD revealed $\alpha$-SiC(6H), $TiB_2$, and YAG($Al_{5}Y_{3}O_{12}$). In pressureless annealing method, the relative density and the mechanical properties of composites were increased with increasing $Al_{2}O_{3}+Y_{2}O_3$ contents because YAG of reaction between $Al_{2}O_3$ and $Y_{2}O_3$ was increased. But In pressured annealing method, reaction between $Al_{2}O_3$ and $Y_{2}O_3$ formed YAG but the relative density decreased with increasing $Al_{2}O_{3}+Y_{2}O_3$ contents. The electrical resistivity of the composites was all positive temperature coefficient resistance (PTCR) in the temperature range of 25$^{\circ}C$ to 700$^{\circ}C$.

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자기 통전식 SiC세라믹 발열체 개발을 위한 기초 특성 연구 (Study of Basic Properties to Develope SiC Ceramic Heater by Self-Charge with Electricity)

  • 신용덕;고태헌;주진영
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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    • pp.124-125
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    • 2007
  • The composites were fabricated $\beta$-SiC and $TiB_2$ powders with the liquid forming additives of 8, 12, 16[wt%] $Al_2O_3+Y_2O_3$ as a sintering aid by pressureless annealing at $1,650[^{\circ}C]$ for 4 hours. Reactions between SiC and transition metal $TiB_2$ were not observed in the microstructure and the phase analysis of the pressureless annealed SiC-$TiB_2$ electroconductive ceramic composites. The relative density, the flexural strength, the Young's modulus and the Vicker's hardness showed the highest value of 82.29[%], 189.5[MPa], 54.60 [GPa] and 2.84[GPa] for SiC-$TiB_2$ composites added with 16[wt%] $Al_2O_3+Y_2O_3$ additives at room temperature. The relative density of SiC-$TiB_2$ composites was lowered due to gaseous products of the result of reaction between SiC and $Al_2O_3+Y_2O_3$. The electrical resistivity showed the lowest value of 0.012[${\Omega}{\cdot}cm$] for 16[wt%] at 25[$^{\circ}C$]. The electrical resistivity was all negative temperature coefficient resistance (NTCR) in the temperature ranges from 25[$^{\circ}C$] to 700[$^{\circ}C$].

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SiC계 세라믹 발열체 경제성 평가 (Economical Estimation of SiC Ceramic Heater)

  • 조현섭;유인호
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2009년도 춘계학술발표논문집
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    • pp.450-453
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    • 2009
  • Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of SiC-based electroconductive ceramic composites. Compare economic estimation of SiC ceramic heater with sheathe heater are as followings. (1) Temperature rising time of sheath heater is 1.1 times faster than SiC ceramic heater. (2) Heating insulation of SiC ceramic heater is 2.7 times larger than sheath heater. If SiC ceramic heater is one body type of a product application, contact resistance will decrease. I think that temperature initial rising time is faster than now. The more SiC ceramic heater is used for a long time, the more economic benefit is larger in the view point of heat insulation.

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In-Situ 반응소결에 의한 전도성 $Si_3N_4$-TiN 복합세라믹스 제조 (Fabrication of Electroconductive $Si_3N_4$-TiN Ceramic Composites by In-Situ Reaction Sintering)

  • 이병택;윤여주;박동수;김해두
    • 한국재료학회지
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    • 제9권6호
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    • pp.577-582
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    • 1999
  • 전도성 $Si_3N_4$-TiN 세라믹 복합재료를 제조하기 위해 성형체를 $1450^{\circ}C$에서 20시간 질화처리한 후 $1950^{\circ}C$에서 3.5시간 가스압소결 기술에 의해 후소결하였다. 초기 분말로 약 $10\mu\textrm{m}$로 된 상용 Si분말, 100mesh와 325mesh로된 Ti분말, 그리고 미세한 $\2.5mu\textrm{m}$ TiN분말을 사용하였다. Ti분말울 사용한 $Si_3N_4$-TiN 소결체에서 상대밀도 및 파괴인성값은 다량의 조대한 기공의 존재로 인하여 낮은 값을 보였다. 그러나 TiN분말을 사용한 $Si_3N_4$-TiN 복합체에서 파괴인성, 파괴강도 및 전기저항은 각각 $5.0MPa{\cdot}m^{1/2}$, 624MPa 그리고 $1400{\omega}cm$였다. 복합체에서 TiN 업자의 분산은 $Si_3N_4$ 업자의 조대한 봉상형태로의 성장올 방해하며 $Si_3N_4$/TiN 계면에 강한 변형장울 만든다. $Si_3N_4$-TiN 복합체의 전기전도도 및 기계적 특성을 향상시키기 위해 TiN 업자가 균일하게 분산 된 미세조직 제어가 요망된다.

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액장 소결에 의한 $\beta-SiC-ZrB_2$ 복합체의 제조와 특성 (Properties and Manufacture of the $\beta-SiC-ZrB_2$ Composited Densified by Liquid-Phase Sintering.)

  • 신용덕;주진영
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제48권2호
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    • pp.92-97
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    • 1999
  • The mechanical and electrical properties of the hot-pressed and annealed $\beta-Sic$+39vol.%$ZrB_2$ electroconductive ceramic composites were investigated as a function of the liquid forming additives of $Al_2O_3+Y_2O_3(6:4wt%)$. In this microstructures, no reactions and elongated $\alpha$-SiC grains with equiaxed $ZrB_2$, gains were observed between $\beta-SiC$ and $ZrB_2$, and the relative density was over 97.6% of the theoretical density. Phase analysis of the composites by XRD revealedmostly of $\alpha$-SiC(6H, 4H), $ZrB_2$, and weakly $\beta-SiC$(15R) phase. The fracture toughness decreased with increasing $Al_2O_3+Y_2O_3$ contents and showed the highest of $6.37MPa.m^{\fraction ane-half}$ for composite added with 4wt% $Al_2O_3+Y_2O_3$ additives at room temperature. The electrical resistivity increased with increasing $Al_2O_3+Y_2O_3$contents and showed the lowest of $1.51\times10^{-4}\Omega.cm$ for composite added with $Al_2O_3+Y_2O_3$ additives at $25^{\circ}C$. This reason is the increasing tendency of pore formation according to amount of liquid forming additives $Al_2O_3+Y_2O_3$. The electrical resistivity of the composites was all positive temperature coefficient resistance(PTCR) against temperature up to $700^{\circ}C$.

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The Development of an Electroconductive SiC-ZrB2 Ceramic Heater through Spark Plasma Sintering

  • Ju, Jin-Young;Kim, Cheol-Ho;Kim, Jae-Jin;Lee, Jung-Hoon;Lee, Hee-Seung;Shin, Yong-Deok
    • Journal of Electrical Engineering and Technology
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    • 제4권4호
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    • pp.538-545
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    • 2009
  • The SiC-$ZrB_2$ composites were fabricated by combining 30, 35, 40 and 45vol.% of Zirconium Diboride (hereafter, $ZrB_2$) powders with Silicon Carbide (hereafter, SiC) matrix. The SiC-$ZrB_2$ composites, the sintered compacts, were produced through Spark Plasma Sintering (hereafter, SPS), and its physical, electrical, and mechanical properties were examined. Also, the thermal image analysis of the SiC-$ZrB_2$ composites was examined. Reactions between $\beta$-SiC and $ZrB_2$ were not observed via X-Ray Diffractometer (hereafter, XRD) analysis. The relative density of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$, and SiC+45vol.%$ZrB_2$ composites were 88.64%, 76.80%, 79.09% and 88.12%, respectively. The XRD phase analysis of the sintered compacts demonstrated high phase of SiC and $ZrB_2$ but low phase of $ZrO_2$. Among the SiC-$ZrB_2$ composites, the SiC+35vol.%$ZrB_2$ composite had the lowest flexural strength, 148.49MPa, and the SiC+40vol.%$ZrB_2$ composite had the highest flexural strength, 204.85MPa, at room temperature. The electrical resistivities of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$ and SiC+45vol.%$ZrB_2$ composites were $6.74\times10^{-4}$, $4.56\times10^{-3}$, $1.92\times10^{-3}$, and $4.95\times10^{-3}\Omega{\cdot}cm$ at room temperature, respectively. The electrical resistivities of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$ SiC+40vol.%$ZrB_2$ and SiC+45[vol.%]$ZrB_2$ composites had Positive Temperature Coefficient Resistance (hereafter, PTCR) in the temperature range from $25^{\circ}C$ to $500^{\circ}C$. The V-I characteristics of the SiC+40vol.%$ZrB_2$ composite had a linear shape. Therefore, it is considered that the SiC+40vol.%$ZrB_2$ composite containing the most outstanding mechanical properties, high resistance temperature coefficient and PTCR characteristics among the sintered compacts can be used as an energy friendly ceramic heater or electrode material through SPS.

고효율 세라믹 발열체 제작 및 특성 시험에 관한 연구 (A Study on the Fabrication and Characteristics of Ceramic Heater Apparatus with High Efficiency)

  • 조현섭;오명관
    • 한국산학기술학회논문지
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    • 제13권3호
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    • pp.1275-1278
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    • 2012
  • 도전성 복합체의 최적 설계 요소와 세라믹 제조기법을 찾고 발열체 제작을 위한 기초기반 기술을 확보하였다. 제품 응용시 세라믹 발열체를 하나의 몸체로 제작하여 접촉 저항을 최대한 줄이면 시스 발열체보다 1.1배 느린 초기 상승 온도 속도를 높일 수 있고, 보온력에서는 SiC계 세라믹 발열체가 시스 발열체보다 약 2.7배 높기 때문에 제품의 사용 기간이 길어질수록 에너지 절감 효과를 얻을 수 있어, 경제성 면에서 대단히 유리하게 평가 된다.