Ultrafast solid-state chemical synthesis of BaTiO3 initiated by gyrotron microwave radiation

TL;DR

This study demonstrates ultrafast synthesis of BaTiO3 using gyrotron microwave radiation, achieving high yields within minutes through localized thermal instabilities in a multimode cavity reactor.

Contribution

It introduces a novel microwave-assisted solid-state synthesis method for BaTiO3 with rapid reaction times and detailed modeling of thermal processes in the reactor.

Findings

Synthesis time reduced to 1.5-7 minutes

Target yield of up to 90% achieved

Localized thermal instabilities reach 670 W/cm³ power

Abstract

This work presents the results of a study on the solid-state synthesis of barium titanate under continuous microwave radiation from a 24 GHz gyrotron in a multimode cavity reactor. It is shown that in localized domains where fine-scale thermal instabilities develop, initiated by microwave radiation within the initial stoichiometric reaction mixture of ultrafine barium carbonate and titanium dioxide powders, the synthesis can proceed within 1,5 - 7 minutes, achieving a target product yield of up to 90%. Based on a developed realistic numerical model of the multimode reactor, involving an iterative solution of stationary Maxwell and heat conduction equations, it is demonstrated that the specific absorbed power in the domains where fine-scale thermal instabilities develop can reach 670 W/cm3 under an input microwave power of 400 W.