Session: CIE-01-01 - AMS: Advanced Modeling and Simulation

Paper Number: 91132

91132 - Localized Dielectric Sintering With Magnetron for Microwave Material Processing 

The process of sintering occurs when enough heating energy is applied on the particles of material precursor powders to coalesce together and form a solid material without melting. Solidification takes place through cross mass diffusion along common interfaces and this technique has been used extensively by the materials processing community for ceramic part manufacturing processes. However, in most cases, furnaces are being used to elevate the temperature of material powder precursors globally throughout the entire volume of the  intended parts. The present work explores the feasibility of using instead,  localized heating induced by utilizing coherent microwave radiation. Microwave-based material processing involves coupling between thermal and electromagnetic physics where the microwave radiation heats the sample locally via volumetrically tailored heat fluxes. However, the heat fluxes change the dielectric properties of the sample, which then in turn affect microwave propagation.  The nonlinearity introduced by the temperature dependence of the material properties into the relevant partial differential equations of this coupled system is further complicated by poorly defined dielectric, thermal, and thermo-electric properties of dielectric precursor powders at temperatures required for sintering.  This work focuses on analyzing a $TE_{106}$ $2.45~GHz$ microwave cavity used for processing $BaTiO_3$, or BTO, precursor powder.  Both a physical and a virtual experiment were carried out in tandem to understand the microwave propagation and dielectric property evolution with respect to temperature $T$.  It was demonstrated that appropriate tuning of the material properties  (i.e., density, specific heat, heat conductivity, dielectric permittivity and loss tangent) relative to temperature enabled localized heating predicted by our model to match that of the physical experiment.

Presenting Author: Benjamin Graber US. Naval Research Laboratory

Presenting Author Biography: Benjamin Graber, Ph.D. is a previous Jerome Karle Research Fellow and recipient of the National Academies Fellowship. He currently works in the Computational Multiphysics group at the U.S. Naval Research Laboratory. His primary research areas are system controls, robotics design, microwave plasma, ceramic sintering, and several fields tangential to additive manufacturing. His modelling work includes microwave sintering of ceramics, plasma element control of microwave radiation, and high temperature thermo-electric systems.

Authors:

Benjamin Graber US. Naval Research Laboratory
Athanasios Iliopoulos US. Naval Research Laboratory
John Michopoulos US. Naval Research Laboratory
John Steuben US. Naval Research Laboratory
Andrew Birnbaum US. Naval Research Laboratory
Edward Gorzkowski US. Naval Research Laboratory
Eric Patterson US. Naval Research Laboratory
Richard Fischer US. Naval Research Laboratory
George Petrov US Naval Research Laboratory
Luke Johnson US. Naval Research Laboratory (former employee)