TY - BOOK

T1 - A Multi-method Atomistic Study of Protective Nitride Coatings: from Crystalline to Amorphous Materials

AU - Nayak, Ganesh Kumar

N1 - no embargo

PY - 2023

Y1 - 2023

N2 - Diffusion plays an important role in the properties of solids, which governs the kinetics of microstructural changes and processes of mass transport. The diffusional phenomena are most widespread in metals, alloys, and metastable and chemically complex solid solutions, mainly at elevated temperatures. For instance, the kinetics in metastable phases, such as oxidation, mixing, intermixing, thermal decompositions, and phase formation, are attributed to the diffusional rearrangement of atoms. Atomistic simulations have provided unprecedented insight into various material properties, with ab initio calculations, in particular, being highly successful in raising the level of understanding close to that of experimental observations. However, diffusion dynamics have been challenging due to the time scale limitation of ab initio molecular dynamics for the infrequent event of jump processes. In contrast, the nudged elastic band method (NEB) based on the transition state theory (TST) can be employed to overcome this shortcoming. This method can calculate the 0 K migration energy barrier of a diffusion process from a static density functional theory (DFT) calculation and the finite temperature diffusion quantities by considering the free energy contribution from phonon. However, the model of an amorphous system, considering the size limitation of ab initio methods to a few hundred atoms, is not large enough to represent real materials. Hence, one needs to consider the large-scale atomistic simulations to predict the properties accurately. In the present thesis, we present the mass transport-related phenomena in B1 nitride coatings using the diffusion migration barriers by the 0 K NEB calculations. In part of the thesis, we use phonon thermodynamics to extend the 0 K calculations to quantify the diffusion of the finite temperatures and pressures (pre-exponential coefficients and activation energies). Further, we train a machine learning interatomic potential (MLIP) and use it in large-scale molecular dynamics to study the structural and elastic properties of amorphous silicon nitrides. Many chemical environments in B1 nitride solid solutions provide a different value of vacancy formation energy and migration energy barriers, namely an "envelope". We use the envelope method to predict phase formation in ternary nitrides. Furthermore, we establish a relation between lattice distortion and sluggish diffusion in high-entropy nitrides (HEN) using the envelope methods.

AB - Diffusion plays an important role in the properties of solids, which governs the kinetics of microstructural changes and processes of mass transport. The diffusional phenomena are most widespread in metals, alloys, and metastable and chemically complex solid solutions, mainly at elevated temperatures. For instance, the kinetics in metastable phases, such as oxidation, mixing, intermixing, thermal decompositions, and phase formation, are attributed to the diffusional rearrangement of atoms. Atomistic simulations have provided unprecedented insight into various material properties, with ab initio calculations, in particular, being highly successful in raising the level of understanding close to that of experimental observations. However, diffusion dynamics have been challenging due to the time scale limitation of ab initio molecular dynamics for the infrequent event of jump processes. In contrast, the nudged elastic band method (NEB) based on the transition state theory (TST) can be employed to overcome this shortcoming. This method can calculate the 0 K migration energy barrier of a diffusion process from a static density functional theory (DFT) calculation and the finite temperature diffusion quantities by considering the free energy contribution from phonon. However, the model of an amorphous system, considering the size limitation of ab initio methods to a few hundred atoms, is not large enough to represent real materials. Hence, one needs to consider the large-scale atomistic simulations to predict the properties accurately. In the present thesis, we present the mass transport-related phenomena in B1 nitride coatings using the diffusion migration barriers by the 0 K NEB calculations. In part of the thesis, we use phonon thermodynamics to extend the 0 K calculations to quantify the diffusion of the finite temperatures and pressures (pre-exponential coefficients and activation energies). Further, we train a machine learning interatomic potential (MLIP) and use it in large-scale molecular dynamics to study the structural and elastic properties of amorphous silicon nitrides. Many chemical environments in B1 nitride solid solutions provide a different value of vacancy formation energy and migration energy barriers, namely an "envelope". We use the envelope method to predict phase formation in ternary nitrides. Furthermore, we establish a relation between lattice distortion and sluggish diffusion in high-entropy nitrides (HEN) using the envelope methods.

KW - first-principle calculation

KW - density function theory

KW - ab initio molecular dynamics

KW - classical molecular dynamics

KW - machine learning interatomic potential

KW - wear protection

KW - nitride protective coatings

KW - B1 nitrides

KW - amorphous nitrides

KW - chemical complex nitrides

KW - high-entropy nitrides

KW - nitride solid solutions

KW - solid lubricant protective coatings

KW - vanadium aluminium nitrides

KW - titanium aluminium nitrides

KW - titanium nitrides

KW - titanium silicon nitrides

KW - silicon nitrides

KW - sluggish diffusion

KW - lattice distortion

KW - diffusion

KW - lattice diffusion

KW - vacancy formation energy

KW - migration energy barriers

KW - migration free energy

KW - phonons

KW - thermodynamics

KW - linear thermal expansion

KW - nudged elastic band

KW - alloying

KW - d-element impurities

KW - enthalpy of formation

KW - activation energy

KW - elastic properties

KW - temperature-dependent elastic properties

KW - crystal orbital Hamilton population

KW - bonding

KW - anti-bonding

KW - First-Principle-Berechnung

KW - Dichtefunktionaltheorie

KW - Ab initio Molekulardynamik

KW - Klassische Molekulardynamik

KW - Maschinell gelernte interatomare Potenziale

KW - Verschleißschutz

KW - Nitridische Schutzschichten

KW - B1-Nitride

KW - Amorphe Nitride

KW - Chemisch komplexe Nitride

KW - Hochentropie-Nitride

KW - Nitrid-Mischkristalle

KW - Festschmierstoff-Schutzbeschichtung

KW - Vanadiumsluminium-Nitride

KW - Titanaluminiumnitride

KW - Titansiliziumnitride

KW - Siliziumnitride

KW - Träge Diffusion

KW - Gitterverzerrung

KW - Diffusion

KW - Gitterdiffusion

KW - Leerstellenbildungsenergie

KW - Migrationsenergiebarrieren

KW - freie Migrationsenergien

KW - Phononen

KW - Thermodynamik

KW - Lineare thermische Expansion

KW - Nudged-Elastic-Band-Methode

KW - Legieren

KW - D-Element Verunreinigungen

KW - Bildungsenthalpie

KW - Aktivierungsenergie

KW - Elastische Eigenschaften

KW - Temperaturabhängige elastische Eigenschaften

KW - Crystal Orbital Hamilton Population

KW - Bindungen

KW - Anti-Bindungen

U2 - 10.34901/mul.pub.2023.286

DO - 10.34901/mul.pub.2023.286

M3 - Doctoral Thesis

ER -