About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
Phase Transformations in Ceramics: Science and Applications
|
| Presentation Title |
Assessing JMAK Kinetics Underlying Mechanochemical Phase Transformations |
| Author(s) |
Angelina Jorgenson, Emma McCarthy, Vipul Jain, Christopher J. Marvel |
| On-Site Speaker (Planned) |
Christopher J. Marvel |
| Abstract Scope |
Mechanochemical reactions are often driven by ball milling, but quantitative kinetic models that predict the extent of mechanochemical phase transformations and describe their mechanistic pathways have yet to be explored. In this work, the viability of the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model was assessed to chart mechanochemistry redox kinetics. An equimolar mixture of NiO was milled with Mn for various times to produce a Ni and MnO phase mixture, and relative phase fractions of NiO:MnO were determined via X-ray diffraction to quantify the completeness of the transformation. The JMAK model identified three distinct kinetic regimes: an initial nucleation-limited stage, an intermediate rapid nucleation and growth stage, and a late-stage reaction-limited regime. Scanning transmission electron microscopy was utilized to identify transformation mechanisms associated with each kinetic regime. This work verified that JMAK can be used as a framework for quantifying reaction progression and identifying changes in phase transformation mechanisms via JMAK exponent determination. |