Semester of Graduation

Spring 2026

Degree

Master of Science in Mechanical Engineering (MSME)

Department

Mechanical & Industrial Engineering

Document Type

Thesis

Abstract

Mechanochemistry, in which mechanical energy inputs drive chemical reactions, is an area of growing interest due to its solid-state approach and ability to produce unique reaction pathways. Though mechanochemical reactions have been extensively demonstrated using high energy ball milling, quantitative kinetic models describing mechanistic pathways are limited. The viability of the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model as a framework to fill this gap in mechanistic understanding was explored through its application to a mechanoreduction reaction between nickel oxide and manganese. The JMAK model identified three distinct kinetic regimes. The extracted Avrami constants were consistent with an initial nucleation-limited stage (n = 0.6), a rapid nucleation and growth stage (n = 2.8), and a late-stage reaction-limited regime (n = 1.7), demonstrating that the mechanochemical transformation proceeds through nucleation and growth processes characteristic of idealized phase transformations. Pre-activation of reactant constituents through pre-milling of manganese and nickel oxide was explored to evaluate the JMAK model ability to resolve kinetic variations. Pre-milling manganese resulted in accelerated reaction incubation, attributed to the increased reactivity of the metallic phase. Though JMAK indicated changing nucleation behavior with pre-treatment, the three-stage mechanistic pathway remained unchanged. Scanning transmission microscopy allowed for visualization of the phase evolution at the nanoscale, revealing a reaction pathway aligning with the JMAK interpretation: early-stage interface formation, intermediate-stage nanocrystalline intermixing and product formation, and late-stage limitations in unconverted regions. Thermo-analytical measurements reflected the increasing reactivity of the reaction mixture with milling time through a trend of lowering peak temperatures. Collectively, this work has verified that JMAK can be used as a framework for mechanochemical kinetics, which enables quantification of reaction progression and a deepened mechanistic understanding. This new insight offers a foundation for future efforts in predicting and tailoring reaction behavior.

Date

4-10-2026

Committee Chair

Marvel, Christopher

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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