Ceramic Interfaces

Chiang, Yet-Ming

Massachusetts Institute of Technology (United States)

关键词: Thermodynamics;    Ceramic;    Thickness Ceramic;    Processing;    36 Materials Science;   

DOI  :  10.2172/839143
RP-ID  :  NONE
RP-ID  :  FG02-87ER45307
RP-ID  :  839143

美国|英语

来源: UNT Digital Library

【 摘 要 】

During the period of this grant, we significantly advanced the understanding of stable surface amorphous films (SAFs), the existence of which was first postulated and then demonstrated under this program. SAFs are nanometer-thick amorphous films which are characterized by a self-selecting thickness, and a composition and structure distinct from the bulk phases with which they coexist. Importantly, they are present as an equilibrium, disordered phase below bulk solidus temperatures where all other phases in the system are crystalline. They are true surface phases which coexist in thermodynamic equilibrium with the bulk phases. We have shown that SAFs form in a number of binary oxide systems, and that they play an important role in the processing of materials (e.g., solid-state activated sintering in ZnO-Bi2O3) and in forming surface-active layers in supported catalyst systems. These experimental results as well as a theoretical model for the stability of SAFs have now been published. We believe that SAFs can be controlled and manipulated in a wide range of systems, with potential applications in nanotechnology, MEMS, microelectronics, adhesion, and colloidal crystals.