Wetting Characteristics and Interfacial Reaction at <TEX>$Al/Al_2O_3$</TEX> Interface

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J. Korean Ceram. Soc. > Volume 31(8); 1994 > Article

Journal of the Korean Ceramic Society 1994;31(8): 815.

$Al/Al_2O_3$ 계면의 젖음특성 및 계면반응

권순용, 정대영, 최시경, 구형회¹, 이종수¹

한국과학기술원 무기재료공학과
¹국방과학연구소 기술연구본부

Wetting Characteristics and Interfacial Reaction at $Al/Al_2O_3$ Interface

ABSTRACT

Sessile drop studies of molten Al on single crystal sapphire substrate were conducted to understand the wetting behavior and interfacial reaction at Al/Al2O3 interface. To investigate the wetting mechanism, the variation in contact angle was determined with time. The contact angle obtained in this study decreased exponentially with time. This result means that the driving force for wetting is the reduction in interfacial energy between liquid Al and sapphire caused by the interfacial reaction. The closer examination revealed that the reaction was the dissolution of sapphire by molten Al. Ti has been frequently used to improve wetting on ceramic materials. Therefore, the influence of Ti content on the wetting behaviour was investigated in this work. The equilibrium wetting angles of pure Al, Al-0.3 wt%Ti, and Al-1.0 wt%Ti at 100$0^{circ}C$ were 63$^{circ}$, 59$^{circ}$, and 54$^{circ}$respectively. The difference is considered as the result of the change in interfacial energy caused by the reaction between Ti and sapphire and the interfacial reaction formed the reaction products of varying stoichiometry (TiO, Ti2O3, TiO2 etc.).