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Phase transformations in thin films
94
AUTHORS' ABSTRACTS
The interaction of small particles and thin films of metals with gases H. POPPA Ames Research Center, NASA, Moffett Field, Calif. 94035 (U.S.A.) (Paper 5-1-1)
The existing work on gas-solid reactions making use of thin film technologies is reviewed. The discussion concentrates on two major areas of gas-metal interactions: chemisorption and the early stages of oxidation of metals, characterized by a nonvolatile reaction product, and catalytic surface reactions, featuring volatile reaction products. In the field of catalysis in particular, it is of importance to distinguish between reactions on continuous thin film substrates and reactions on particulate deposits. In the latter case, the size and structure of small metallic clusters (10-100 A) can play a decisive role in determining reaction chemistry. Small-particle-gas interactions also affect the nucleation, growth and sintering processes of thin films. It is shown that various combinations of UHV and high resolution electron microscopy techniques, which include in situ experimentation, can provide the appropriate tools for studying "~ngstr6m-particle chemistry".
Phase transformations in thin films
S. MADER IBM Corporation, East Fishkill Facility, Hopewell Junction, N.Y. 12533 (U.S.A.)
(Paper 5-R-2)
Several aspects which cause phase transformations in films to differ from those in bulk material are reviewed. Amorphous to crystalline transformations and precipitation effects in Fe-Au films are described. The influence of film surfaces on precipitation is discussed.
AUTHORS' ABSTRACTS
The interaction of small particles and thin films of metals with gases H. POPPA Ames Research Center, NASA, Moffett Field, Calif. 94035 (U.S.A.) (Paper 5-1-1)
The existing work on gas-solid reactions making use of thin film technologies is reviewed. The discussion concentrates on two major areas of gas-metal interactions: chemisorption and the early stages of oxidation of metals, characterized by a nonvolatile reaction product, and catalytic surface reactions, featuring volatile reaction products. In the field of catalysis in particular, it is of importance to distinguish between reactions on continuous thin film substrates and reactions on particulate deposits. In the latter case, the size and structure of small metallic clusters (10-100 A) can play a decisive role in determining reaction chemistry. Small-particle-gas interactions also affect the nucleation, growth and sintering processes of thin films. It is shown that various combinations of UHV and high resolution electron microscopy techniques, which include in situ experimentation, can provide the appropriate tools for studying "~ngstr6m-particle chemistry".
Phase transformations in thin films
S. MADER IBM Corporation, East Fishkill Facility, Hopewell Junction, N.Y. 12533 (U.S.A.)
(Paper 5-R-2)
Several aspects which cause phase transformations in films to differ from those in bulk material are reviewed. Amorphous to crystalline transformations and precipitation effects in Fe-Au films are described. The influence of film surfaces on precipitation is discussed.