טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentGutman Itamar
SubjectFormation Structure and Properties of Periodic Structures
at SiO2-Mg Interface
DepartmentDepartment of Mechanical Engineering
Supervisors Professor Shapiro Michael
Dr. Gotman Irena
Full Thesis textFull thesis text - English Version


Abstract

The investigation and fabrication of multilayered materials are of great interest because of numerous technological applications requiring special electrical, optical and/or mechanical properties. Multilayered materials can be used for production of multi-layered capacitors, electrical junctions based on superconducting devices, improved flat-panel displays and etc. and are usually fabricated employing complex processes such as: laser interference or ablation, magnetron and ion beam sputtering techniques.

In some unique cases solid-state interaction between metal and ceramics or intermetallic compounds, in the form of diffusion couples can result in the growth of a periodically multi-layered reaction zone, consisting of alternating layers of the reaction products. In this case, multi-layered structures can be grown in a relatively simple manner requiring only basic laboratory facilities.

During the study of the solid-state reaction in the SiO2/Mg system, periodically spaced layers of different chemical composition were found. Such periodic structures may possess unique physical and mechanical properties stemming from their anisotropy.

In this study we have focused on chemical and morphological characterization of the SiO2/Mg system’s periodic layers, the reaction kinetics, as well as mechanical and electrical properties. A physical mechanism and a mathematical model for the formation of periodically spaced layers in this couple are proposed based on the experimental observations. The model allows rationalization of the temporal evolution of periodic layers’ thicknesses at different temperatures.