Lithium orthosilicate ceramics with preceramic polymer as silica source

Lithium orthosilicate ceramics powders were synthesized using a preceramic polymer as the source of silica. Stoichiometric, as well as batches lean and rich in lithium, were prepared by the said approach to understand the thermal stability of the orthosilicate phase at 1000 °C. All of the batches produced phase pure orthosilicate ceramics with sintered density up to 82%. However, different batches showed markedly different microstructural evolution with the lithium lean and stoichiometric compositions exhibiting formation of flower-like lithium metasilicate phase. The lithium rich composition showed no phase separation of the orthosilicate ceramic phase as confirmed by electron microscopy and x-ray diffraction. The high volatilization of the lithium species at high temperature was ascribed to the phase separation of the orthosilicate phase in the lithium lean compositions. The current report provides an alternative and novel method to fabricate lithium orthosilicate, and shows promise for application as tritium breeding blankets in fusion technologies.