Prof. Wayne D. Kaplan

Wayne D. Kaplan
De Jour, 606

  • B.Sc. 1989 (Technion)
  • M.Sc. 1991 (Technion)
  • D.Sc. 1994 (Technion)

On receiving his doctorate, Prof. Kaplan spent one year as a Humboldt fellow at the Max-Planck-Institut für Metallforschung, Stuttgart. He was also a visiting scientist at N.I.S.T. during the summer of 1994, and spent three months as a Minerva Fellow at the Max-Planck-Institut für Metallforschung, Stuttgart (1992). In 1995 he joined the Department of Materials Science & Engineering at the Technion. He is a member of the Materials Research Society, the American Ceramic Society and the Israel Microscopy Society.

Microstructural design objectives for metal-ceramic joints and composites are often limited by the nature of the metal-ceramic interface. Two very different materials must be brought into contact with a specific interfacial geometry, and a physico-chemical bond must be formed between them. The process may include the formation of interface phases due to chemical reactions, both between the components and with the process atmosphere. The chemical and mechanical stability of the interface is dependent on the possibility of interface reactions as well as on the interface microstructure, which includes the interfacial discontinuity associated with the change in the chemical bond type. While the properties of metal-ceramic components are sensitively dependent on the properties of the joint forming materials, the structure and quality of the interfacial bond is often the major factor which determines the final macro-properties. An understanding of the chemical nature of the metal-ceramic interface, as well as its microstructure and crystallography, is critical for the successful development of metal-ceramic joints and components.

Two main experimental techniques are adapted to these issues. In the first, contact angles between liquid metals and ceramic substrates are measured in-situ and dynamically, under controlled temperature and gas partial pressures. In addition, the energy of solid-solid interfaces is determined via Winterbottom analysis. Secondly, quantitative high resolution transmission electron microscopy (HRTEM) and analytical electron microscopy (AEM) are applied to study the metal-ceramic interfaces formed during the wetting experiments. In-situ HRTEM using a TEM hot-stage provides direct information on wetting, reactions, segregation, and ordering at the atomic level.