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Exploring Crystallization Phenomena in Al2TiO5-Based Chemical Vapor-Deposited Coatings by in Situ Transmission Electron Microscopy

Year: 2023

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Understanding crystallization is crucial to enable improved design approaches for inorganic materials. Despite this importance, a deepened understanding of the mechanisms controlling this phase transition is still lacking. Herein, we employ in situ heating in a transmission electron microscope (TEM) to unravel crystallization phenomena in an Al–Ti–O system. Specifically, annealing of amorphous chemical vapor deposited (CVD) Al 2 TiO 5 -based coatings has been carried out in the temperature interval 700–900 °C. Crystallization typically occurs through a two-step process, where numerous smaller (<10 nm) crystals are initially formed, followed by rapid crystal growth. Examinations of the initial crystallization stages indicate that the amorphous-to-crystalline transformation is polymorphic and that several phases may nucleate simultaneously, including Al 6 Ti 2 O 13 and Al 16 Ti 5 O 34 . A transient (time-dependent) nucleation rate is discovered based on the displayed nucleation behavior. Subsequent evaluations of the growth stages also reveal a preferential growth into larger crystals, and the coherent findings of this study indicate that crystallization occurs through a diffusionless (displacive) mechanism.

Source: Crystal Growth & Design

DOI: 10.1021/acs.cgd.3c00395

Authors: Sebastian Öhman, Olivier Donzel-Gargand, Mats Boman, Tobias Törndahl

Institution: Uppsala University

Language: English

Topic: Advanced ceramic materials synthesis

Subfield: Ceramics and Composites

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $5,000

Funders: Vetenskapsrådet, Stiftelsen för Strategisk Forskning