자기 통전식 SiC 세라믹 발열체 개발을 위한 기초 특성 연구

신용덕(Yong-Deok Shin),고태헌(Tae-Hun Ko),주진영(Jin-Young Ju) 대한전기학회 2007 대한전기학회 학술대회 논문집 Vol.2007 No.11

The composites were fabricated β-SiC and TiB₂ powders with the liquid forming additives of 8, 12, 16[wt%] Al₂O₃+Y₂O₃ as a sintering aid by pressureless annealing at 1,650[℃] for 4 hours. Reactions between SiC and transition metal TiB₂ were not observed in the microstructure and the phase analysis of the pressureless annealed SiC-TiB₂ 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[㎫], 54.60[㎬] and 2.84[㎬] for SiC-TiB₂ composites added with 16[wt%] Al₂O₃+Y₂O₃ additives at room temperature. The relative density of SiC-TiB₂ composites was lowered due to gaseous products of the result of reaction between SiC and Al₂O₃+Y₂O₃. The electrical resistivity showed the lowest value of 0.012[Ω · ㎝] for 16[wt%] at 25[℃]. The electrical resistivity was all negative temperature coefficient resistance (NTCR) in the temperature ranges from 25[℃] to 700[℃].

液狀燒結한 SiC系의 傳導性 複合體의 微細構造와 特性에 미치는 Boride의 影響

辛龍德(Yong-Deok Shin),朱陳榮(Jin-Young Ju),高台憲(Tae-Hun Ko) 대한전기학회 2007 전기학회논문지 Vol.56 No.9

The composites were fabricated. respectively, using 61[vol.%] SiC-39[vol.%] TiB₂ and using 61[vol.%] SiC-39[vol.%] ZrB₂ powders with the liquid forming additives of 12[wt%] Al₂O₃+ Y₂O₃ by hot pressing annealing at 1650 [℃] for 4 hours. Reactions between SiC and transition metal TiB₂. ZrB₂ were not observed in this microstructure. The result of phase analysis of composites by XRD revealed SiC(6H. 3C), TiB₂; ZrB₂ and YAG(Al?Y₃O₁₂) crystal phase on the Liquid-Phase-Sintered(LPS) SiC-TiB₂. and SiC-ZrB₂ composite. β→a-SiC phase transformation was occurred on the SiC-TiB₂ and SiC-ZrB₂ composite. The relative density, the flexural strength and Young's modulus showed the highest value of 98.57[%], 249.42[㎫] and 91.64[㎬] in SiC-ZrB₂ composite at room temperature respectively. The electrical resistivity showed the lowest value of 7.96×10?⁴[Ωㆍ㎝] for SiC-ZrB₂ composite at 25[℃], The electrical resistivity of the SiC-TiB₂ and SiC-ZrB₂ composite was all positive temperature coefficient resistance (PTCR) in the temperature ranges from 25[℃] to 700[℃]. The resistance temperature coefficient of composite showed the lowest value of 1.319×10?³/[℃] for SiC-ZrB₂ composite in the temperature ranges from l00[℃] to 300[℃]. Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of SiC-based electroconductive ceramic composites.

원적외선 세라믹 건조기 개발

주진영(Jin-Young Ju),신용덕(Yong-Deok Shin),고태헌(Tae-Hun Ko),이정훈(Jung-hoon Lee) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.5

원적외선 세라믹 건조기를 개발하기 위하여 탄화규소가 주원료로한 세라믹 발열판을 제작하여 건조기 내부에 설치하여 실험하였다. 발열판 장착위치에 따른 실험결과 위치는 큰 변수가 되지 않았고, 기존 5[㎾]용량의 씨즈 히터를 2[㎾]의 세라믹 발열판으로 대체하면서 에너지 절약형 원적외선 세라믹 건조기를 제작할 수 있었다. 또한 발열판 자체 온도 분포를 측정한 결과 시간이 흐름에 따라 온도 분포는 약간의 차이가 있기는 하지만 대체적으로 균일한 분포를 나타내었다. 사용에 따른 경년변화를 측정하기 위해 90시간 동안 부하를 걸어 실험하였지만 발열판 자체의 저항이나 소비전력의 변화는 나타나지 않았다.

Effect of In Situ YAG on Properties of the Pressureless-Sintered SiC-ZrB₂ Electroconductive Ceramic Composites

신용덕(Yong-Deok Shin),주진영(Jin-Young Ju),고태헌(Tae-Hun Ko),이정훈(Jung-hoon Lee) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.7(초록집)

방전플라즈마 소결에 의한 자기 통전식 SiC계 세라믹 발열체 개발

신용덕(Yong-Deok Shin),최원석(Won-Seok Choi),고태헌(Tae-Hun Ko),이정훈(Jung-Hoon Lee),주진영(Jin-Young Ju) 대한전기학회 2009 전기학회논문지 Vol.58 No.4

The composites were fabricated by adding 0, 15, 30, 45[vol.%] ZrB₂ powders as a second phase to SiC matrix. The physical, mechanical and electrical properties of electroconductive SiC ceramic composites by spark plasma sintering(SPS) were investigated. Reactions between β-SiC and ZrB₂ were not observed in the XRD and the phase analysis of the electroconductive SiC ceramic composites. The relative density of mono β-SiC, β-SiC+15[vol.%]ZrB₂, β-SiC+30[vol.%]ZrB₂ and β-SiC+45[vol.%]ZrB₂ composites are respectively 99.24[%], 87.53[%], 96.41[%] and 98.11[%]. Phase analysis of the electroconductive SiC ceramic composites by XRD revealed mostly of β-SiC, ZrB₂ and weakly of ZrO₂ phase. The flexural strength showed the lowest of 114.44[MPa] for β-SiC+15[vol.%] ZrB₂ powders and showed the highest of 210.75[㎫] for composite no added with ZrB₂ powders at room temperature. The trend of the mechanical properties of the electroconductive SiC ceramic composites is accorded with the trend of the relative density. The electrical resistivity of the electroconductive SiC ceramic composites decreased with increased ZrB₂ contents. The electrical resistivity of mono β-SiC, β-SiC+15[vol.%]ZrB₂, β -SiC+30[vol.%]ZrB₂ and β-SiC+45[vol.%]ZrB₂ composites are respectively 4.57×10-1, 2.13×10-1, 2.68×10-2 and 1.99×10-2[Ωㆍ㎝] at room temperature. The electrical resistivity of mono β-SiC and β-SiC+15[vol.%]ZrB₂ are negative temperature coefficient resistance(NTCR) in temperature ranges from 25[℃] to 100[℃]. The electrical resistivity of β-SiC+30[vol.%]ZrB₂ and β-SiC+45[vol.%]ZrB₂ are positive temperature coefficient resistance(PTCR) in temperature ranges from 25[℃] to 100[℃]. It is convinced that β-SiC+30[vol.%]ZrB₂ composites by SPS for heater or ignitors can be applied.

常壓燒結한 SiC-ZrB₂ 電導性 複合體의 特性에 미치는 In Situ YAG의 影響

辛龍德(Yong-Deok Shin),朱陣榮(Jin-Young Ju),高台憲(Tae-Hun Ko),李政勳(Jung-Hoon Lee) 대한전기학회 2008 전기학회논문지 Vol.57 No.11

The effect of content of Al₂O₃+Y₂O₃ sintering additives on the densification behavior, mechanical and electrical properties of the pressureless-sintered SiC-ZrB₂ electroconductive ceramic composites was investigated. The SiC-ZrB₂ electroconductive ceramic composites were pressurless-sintered for 2 hours at 1,700[℃] temperatures with an addition of Al₂O₃+Y₂O₃(6 : 4 mixture of Al₂O₃ and Y₂O₃) as a sintering aid in the range of 8 ~ 20[wt%]. Phase analysis of SiC-ZrB₂ composites by XRD revealed mostly of α-SiC(6H), ZrB₂ and In Situ YAG(A1?Y₃O₁₂). The relative density, flexural strength, Young's modulus and vicker's hardness showed the highest value of 89.02[%], 81.58[㎫], 31.44[㎬] and l.34[㎬] for SiC-ZrB₂ composites added with 16[wt%] Al₂O₃+Y₂O₃ additives at room temperature respectively. Abnormal grain growth takes place during phase transformation from β-SiC into α-SiC was correlated with In Situ YAG phase by reaction between Al₂O₃ and Y₂O₃ additive during sintering. The electrical resistivity showed the lowest value of 3.14×10?²Ωㆍ㎝ for SiC-ZrB₂ composite added with 16[wt%] Al₂O₃+Y₂O₃ additives at 700[℃]. The electrical resistivity of the SiC-TiB₂ and SiC-ZrB₂ composite was all negative temperature coefficient resistance (NTCR) in the temperature ranges from room temperature to 700[℃]. Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of SiC-based electroconductive ceramic composites.

Effect of Pressure on Properties of the SiC-TiB₂ Electroconductive Ceramic Composites

신용덕(Yong-Deok Shin),서재호(Je-Ho Seo),주진영(Jin-Young Ju),고태헌(Tae-Hun Ko),이정훈(Jung-hoon Lee) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.7(초록집)

무가압 어닐드한 SiC-TiB₂ 전도성 복합체의 특성에 미치는 In Situ YAG의 영향

辛龍德(Yong-Deok Shin),朱陳榮(Jin-Young Ju),高台憲(Tae-Hun Ko) 대한전기학회 2008 전기학회논문지 Vol.57 No.5

The composites were fabricated 61[vol.%] β-SiC and 39[vol.%] TiB₂ powders with the liquid forming additives of 8, 12, 16[wt%] Al₂O₃+Y₂O₃ as a sintering aid by pressureless annealing at 1650[℃] for 4 hours. The present study investigated the influence of the content of Al₂O₃+Y₂O₃ sintering additives on the microstructure, mechanical and electrical properties of the pressureless annealed SiC-TiB₂ electroconductive ceramic composites. Reactions between SiC and transition metal TiB₂ were not observed in the microstructure and the phase analysis of the pressureless annealed SiC-TiB₂ electroconductive ceramic composites. Phase analysis of SiC-TiB₂ composites by XRD revealed mostly of α -SiC(6H), β-SiC(3C), TiB₂, and In Situ YAG(Al?Y₃O₁₂). The relative density of SiC-TiB₂ composites was lowered due to gaseous products of the result of reaction between SiC and Al₂O₃+ Y₂O₃. There is another reason which pressureless annealed temperature 1650[℃] is lower 300-450[℃] than applied pressure sintering temperature 1950-2100[℃]. 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-TiB₂ composites added with 16[wt%] Al₂O₃+Y₂O₃ additives at room temperature. Abnormal grain growth takes place during phase transformation from β-SiC into α-SiC was correlated with In Situ YAG phase by reaction between Al₂O₃ and Y₂O₃ additive during sintering. The electrical resistivity showed the lowest value of 0.0117[Ω. ㎝] for 16[wt%] Al₂O₃+Y₂O₃ additives at 25[℃]. The electrical resistivity was all negative temperature coefficient resistance (NTCR) in the temperature ranges from 25℃ to 700[℃]. The resistance temperature coefficient of composite showed the lowest value of -2.3×10?³[℃]?¹ for 16[wt%] additives in the temperature ranges from 25[℃] to 100[℃].

SPS에 의한 SiC-ZrB₂ 도전성 복합체 특성

신용덕(Yong-Deok Shin),주진영(Jin-Young Ju),김철호(Cheol-Ho Kim),이희승(Hee-Seung Lee),고태헌(Tae-Hun Ko),이정훈(Jung-Hoon Lee) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7

The composites were fabricated by adding 30, 35, 40,45vol.% Zirconium Diboride(ZrB₂) powders as a second phase to Silicon Carbide(SiC) matrix. The physical, mechanical and electrical properties of electroconductive SiC-ZrB₂ ceramic composites by Spark Plasma Sintering(SPS) were examined. the relative density of SiC+30vol.%ZrB₂, SiC+35vol.%ZrB₂, SiC+40vol.%ZrB₂, and SiC+45vol.%ZrB₂ composites are 88.64, 76.80, 79.09, and 88.12%, respectively. The XRD phase analysis of the electroconductive SiC-ZrB₂ ceramic composites not observed reactions between β-SiC and ZrB₂, and reveals high of SiC and ZrB₂ , and low of ZrO₂ phase. The electrical resistivity of SiC+30vol.%ZrB₂, SiC+35vol.%ZrB₂, SiC+40vol.%ZrB₂, and SiC+45vol.%ZrB₂ composites are 6.74×10?⁴, 4.56×10?³, 1.92×10?³, and 4.95×10?³Ω · ㎝ at room temperature, respectively. And all of that have Positive Temperature Coefficient Resistance(PTCR) in temperature range from 25℃ to 500℃