Millimeter-Wave Gyrotron System for Research and Application Development. Part 2. High-Temperature Processes in Polycrystalline Dielectric Materials

Abstract

Gyrotron systems operated at frequencies of 24 to 30 GHz with an output power of 3 to 15 kW have been used at the Institute of Applied Physics of the Russian Academy of Sciences for more than 20 years for the studies of high-temperature processes in polycrystalline dielectric materials under intense electromagnetic irradiation. The research has mostly been focused on the study of the physically specific features of diffusive mass transfer in solids and on the possible use of these features for applications. A distinguishing feature of the studied processes is a significant enhancement of their rates compared to similar processes performed with the use of conventional heating methods. Examples of enhanced sintering of a broad range of ceramic materials, including optical and laser ceramics and composition-graded metal–ceramic products are considered. The principles of the developed method of ultrafast sintering of oxide ceramics with rates exceeding those typical of the conventional methods by two or three orders of magnitude are described. The development of this method has resulted from a purposeful use of the functional capabilities of the gyrotron systems and the engineering solutions implemented therein.