Alumimium Titanate-Mullite 복합체: Part1, 열적 내구성

Alumimium Titanate-Mullite Composites : Part1,Thermal Durability

  • 김익진 (서울교육대학교 탄소화학연구소) ;
  • 강원호 (단국대학교 재료공학과) ;
  • 고영신 (서울교육대학교 탄소화학연구소)
  • 발행 : 1993.12.01

초록

Alumimium Titanate-Mullite 복합체는 $Al_{2}O_{3}$분말 알콜용액에서 $Si(OC_{2}H_{5})_{4}$$Ti(OC_{2}H_{5})_4$ 의 단계적인 가수분해로 합성하였다. Sol-Gel 방법으로 합성된 모든 분말은 비정질과 단분산이고 좁은 분말크기의 분포를 보였다. 소결체($1600 ^{\circ}C$/2h)는 임계분해온도인 $1100^{\circ}C$에서 100시간 동안과 750와 $1400^{\circ}C$ 100시간동안 반복적인 열적 내구성 및 열충격 시험을 수행하였다. 가장 좋은 열적 내구성은 aluminium titanate함유량이 70rhk 80vol%일때 얻어졌으며, 이들은 위 실험을 한후 아주 적은 미세구조와 열팽창 곡선의 변화를 나타내었다. 소결체 미세구조의 붕괴는 주사현미경, X-선회절분석과 Dil-atometer로 연구하였다. 위 연구는 이와같은 과정에 의하여 합성된 aluminium titanate-mullite복합체의 서비스 수명을 예상하기 위하여 시도되었다.

The composites in the system aluminium titanate-mullite were synthesized by stepwise alkoxide hydrolysis of tetraethylorthosilicate, Si(OCLH5), and titaniumtetraethoxide, $Ti(OC_{2}H_{5})_4$ in $Al_{2}O_{3}$ ethanolic colloidal solution. All particles produced by sol-gel-process were amorphous, monodispesed and had a narrow particle size distribution. Sintered bodies at $1600 ^{\circ}C$ for 2h were subjected to prolonged durability tests-on the one hand annealing at the critical decomposition temperature of $1100 ^{\circ}C$ for lOOh and on the other cyclic thermal shock between 750 and $1400 ^{\circ}C$ for 100h. The best thermal durability was achieved by a composition containing 70 and 80 vol% aluminium titanate, which showed little change in microstructure and thermal expansion cycles during the tests. The microstructural degradation of samples studied using scanning electron microscopy, X-ray diffraction, and dilatometry, was presented here. The study was conducted in order to predict the service life of aluminium titanate-mullite ceramics formed by this processing route.

키워드

참고문헌

  1. Volkswagen Ag Research Division D-3180 Wolfsburg Experimental results with ceramic components in passenger-car diesel engines H.Heinrich;M.Langer;J.E.Siebels
  2. Acta Cryst. v.B28 Structure studies in $Al_2TiO_5$ at room temperature and at 600˚C B.Morcsin;R.W.Lynch
  3. J. Am. Ceram. Soc. v.70 no.8 Grain boundary microcracking due to thermal expansion anisortropy in aluminium titanate ceramics Y.Ohya;Z.Nakagawa
  4. J. Am. Ceram. Soc. v.63 Decomposition kinetics of $Al_2TiO_5$ in powdered state. E.Kato;K.Daimon;I.Takahashi
  5. J. Am. Ceram. Soc. v.55 Acoustic Emission of aluminium titanate R.E.Wright
  6. Arm. Khim. Zh. v.26 Dilatometric Research of solid Solution on the Basis of Aluminium Titanate (Russ) S.A.Babayan;L.A.Kostanyan;J.A.Geodakyan
  7. Br. Ceram. Trans. J. v.88 Aluminium titanate-A literature reveiw : microcraking phenomena H.A.J.Thomas;R.Sterens
  8. Sprechsaal v.118 no.12 Verbesserung von Aluminiumtitanat-Keramik Ch.Han;D.Selb
  9. J. Am. Ceram. Soc. v.56 no.8 Influence of Grain Size on Effects of Thermal Expansion Anisotropy in Mg$Ti_2O_5$ J.A.Kuszyk;R.C.Bradt
  10. Dissertation, Institut fur Gesteinshuttenkunde Anwendung des Sol-Gel-Verfahrens auf die Herstellung Keramischer Werstoffe aus Aluminiumtitanat-Mullit I.J.Kim
  11. Ceram. Age 60 Thermal expansion hysteresis of aluminium titanate W.R.Buessem;N.R.Thielke;R.V.Sarakauskas
  12. J. Less. Common. Met. v.24 no.2 Thermal expansion characteristics and stablity of pseudobrookitetype compounds M₃$O_5$ G.Bayer