Abnormal grain growth of rutile TiO2 induced by ZrSiO4

TL;DR

This study investigates abnormal grain growth in rutile TiO2 caused by zirconium silicate, revealing that specific doping methods do not induce AGG and suggesting mechanisms involving orientation relationships and grain boundary liquids.

Contribution

The paper uncovers the conditions under which abnormal grain growth occurs in rutile TiO2 and explores the role of ZrSiO4 and doping methods in this process.

Findings

AGG observed in rutile TiO2 with ZrSiO4 presence

Zr and Si doping alone do not cause AGG

Orientation relationships and grain boundary liquids influence AGG

Abstract

Abnormal grain growth (AGG) was observed in rutile TiO2 formed by the thermal treatment of anatase TiO2 in the presence of zirconium silicate. This morphological behaviour was seen to occur in sintered powder compacts and thin films with solid state zircon dopants and in TiO2 coatings on grains of zircon sand. In order to clarify the mechanism of AGG in this system, various doping methods were employed and the morphological consequences of these doping methods were investigated. It was found that doping by Zr and Si does not give rise to abnormal grain growth. The observed phenomena were discussed in terms of morphological and energetic considerations. It is likely that a distinct orientation relationship between rutile TiO2 and ZrSiO4 and possible grain boundary liquid formation play a role in giving rise to the rapid growth of faceted prismatic rutile.