Microstructural Evolution During Sintering with Control of the Interface Structure

Abstract

This paper reports recent theoretical perspectives and experimental results on microstructural evolution during sintering in terms of the interface structure, which is either rough (atomically disordered) or faceted (atomically ordered). The paper presents theoretical predictions and calculations of grain growth during liquid‐phase sintering based on crystal growth theories. It is shown that various types of grain growth behavior, which may be normal, abnormal, or stagnant, can appear as a result of the coupling effects of the maximum driving force for growth and the critical driving force for appreciable growth. The predictions are also shown to be valid in the case of solid‐state sintering. A number of experimental observations showing the effect of some critical processing parameters have been found to be in excellent agreement with the predictions. Principles of microstructure development (grain growth control) during sintering are suggested. In addition, the effect of the interface structure on densification is briefly described and discussed.

Microstructure and mechanical properties of WC–40vol%Al2O3 composites hot pressed with MgO and CeO2 additives

“…During the sintering process, grain boundary complexion transition may occur, in the faceted systems, there existed more than one type of growth behavior. According to the theoretical predictions and investigation of Kang et al [28], the WC grain growth behavior and microstructural evolution during hot pressing could be investigated with respect to the variation of critical driving force (Dg c ) relative to the maximum driving force (Dg max ). The critical driving force is expressed as [29,30],…”

Growth of single crystalline seeds into polycrystalline strontium titanate: Anisotropy of the mobility, intrinsic drag effects and kinetic shape of grain boundaries

“…Another possibility is given by the theory of nucleation barriers, which was mostly developed based on barium titanate [30][31][32][59][60][61][62]. The authors assume an energetic barrier (''nucleation barrier'') for facetted grain boundaries, which represents the energy needed to create a nucleus on a facetted boundary plane for moving the grain boundary.…”

Molten Salt Synthesis of Ceramic Powders

“…The exceptions are observed in highly faceted particles. The highly faceted surfaces have a high degree of smoothness at the atomic scale and high step energy, and their growth is sluggish (Kang et al, 2009 (Kimura & Yoshida, 2006). If the surfaces of the particles formed in the reaction stage have higher interfacial energy than those of the equilibrium form, the particle shape changes to reduce the total interfacial energy.…”

“…Therefore, a larger growth rate is expected at higher temperatures. The growth rate of surfaces with well-developed facets is low because of a smooth surface structure at the atomic scale (Kang et al, 2009). The effect of solubility on the growth rate is observed in the ferrite system.…”