Rodger D. Blake

Ceramic—ceramic seals by microwave heating

Several conclusions may be drawn from this work. First, less energy is required to form a glass-ceramic seal by microwave heating than by conventional heating. Second, less time is required to form the seal by microwave heating, and third, the seal composition is different, and the bonding is different. The micostructure of the seal formed by microwave heating reflects extensive diffusion of the glass constitients throughout the alumina substrate; and alumina throughout the seal glassy matrix. Fourth, higher heating rates are possible with microwave heating than with conventional heating. Last, the energy is coupled differently to the reactants using microwave heating, and thus the reaction kinetics may be different, as indicated by the vastly different microstructures obtained.

Cation diffusion in glass heated using 2.45 GHz radiation

Etude de la diffusion des ions Co, Na, Ni, Cu, Zn dans un verre pyrex a differentes temperatures par retrodiffusion electronique

Microwave sintering of boron carbide

A method for forming boron carbide into a particular shape and densifying the green boron carbide shape. Boron carbide in powder form is pressed into a green shape and then sintered, using a microwave oven, to obtain a dense boron carbide body. Densities of greater than 95% of theoretical density have been obtained. 1 tab.

Thermal processing of ilmenite and titania-doped haematite using microwave energy

To test the potential for microwave processing of lunar materials the heating of ilmenite-rock mixtures, and TiO2-doped haematite were investigated using microwave radiation, llmeniterich rocks will couple, without a coupling agent, to microwave radiation. The microwave experiments are repeatable. Attempts to couple TiO2-doped haematite to microwave radiation were very successful, with susceptibility increasing with TiO2 content. Scanning electron microscopy (SEM) showed increased grain size and particle size with increased TiO2 content in the microwave-heated products of the haematite-TiO2 system. The differences between microwave and furnace melts of ilmenite-rich rocks were also investigated. Petrographic analysis revealed a large amount of titanomagetite in microwave melts while furnace melts contained a large amount of haematite, but the cause of this difference is not fully understood.