Inherent heating instability of direct microwave sintering process: Sample analysis for porous 3Y-ZrO2

TL;DR

This study investigates the inherent heating instability in direct microwave sintering of porous 3Y-ZrO2, explaining it through coupled modeling and experimental analysis, highlighting the influence of material properties and sample positioning.

Contribution

It introduces a novel explanation for microwave sintering instability by coupling effective medium approximation with finite-element modeling, supported by experimental validation.

Findings

Dielectric permittivity's imaginary part increases with temperature, promoting hot spots.

Sample position significantly affects heating uniformity.

Material properties influence the stability of microwave sintering.

Abstract

Direct microwave heating of 3Y-ZrO 2 is studied at frequency of 2.45 GHz. Different conditions of input power, sample position and size are tested. For the first time, the experimentally known instability of microwave sintering is explained coupling the effective medium approximation and finite-element method. We show how the material dielectric permittivity imaginary part which increases with temperature and relative density encourages high hot spot phenomena. It is shown that the sample location has a great impact on the