The UTC Graduate School is pleased to announce that Atal Bhowmik will present Master’s research titled, Density Functional Theory Modeling of Heterogeneous Reactions of Hydrocarbon Intermediates on Silicon Carbide: Surrogate Kinetic Model Development for Chemical Vapor Infiltration on 06/26/2025 at 11.30 AM in EMCS 426, Maytag Room. Everyone is invited to attend.
Engineering
Chair: Murat Barisik
Co-Chair: Kidambi Sreenivas, Reetesh Ranjan
Abstract:
Chemical Vapor Infiltration (CVI) is a well-established fabrication technique used to produce Silicon Carbide (SiC) Ceramic Matrix Composites for enhanced properties. Methyl trichlorosilane (MTS) is the most commonly used precursor for depositing SiC on the substrate surface. The decomposition of MTS involves a set of surface reactions. Characterizing and modelling the surface reactions is crucial in identifying the rate-limiting steps of MTS decomposition. The heterogeneous surface reactions are studied using first-principles calculations. Density Functional Theory (DFT) is applied to search for the transition states of the reactions. The accurate description of Generalized Gradient Approximation (GGA-PBE) and Projector Augmented-Wave (PAW) method is implemented in the quantum mechanical calculations. Through potential energy surface mapping by Nudged Elastic Band (NEB) and Climbing Image NEB (CI-NEB) calculations, the study examines several surface reactions (SR1–SR8). The results exhibit a mix of barrierless and activated processes. The vibrational frequencies of the system are calculated using the finite displacement method. The thermodynamic properties of the reactions are obtained using the vibrational frequencies. All the statistical thermochemistry calculations are simplified using surrogate surface chemistry modelling through the Arrhenius form of the reaction rate equation. The surrogate model characterizes the reactions using a set of Arrhenius parameters. Other reactions proceed with ease, but the SR8 reaction is depicted as a rate-controlling, two-step process with high energy barriers.