About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
Molecular Approaches to Ceramics; Synthesis, Processing, Modeling, and Derived Ceramics
|
| Presentation Title |
Chemical and Structural Evolution of MXene-SiOC Under Ground- and Micro-Gravity and Controlled Atmospheres |
| Author(s) |
Kathy Lu, Mubina Shaik, Muhammad Ahmad |
| On-Site Speaker (Planned) |
Kathy Lu |
| Abstract Scope |
Silicon oxycarbide (SiOC) matrix composites reinforced with two-dimensional MXene (Ti₃C₂Tₓ) were synthesized via vacuum pyrolysis under both Earth-normal gravity and microgravity conditions to investigate the influence of reduced gravitational acceleration on composite structure and oxidation resistance. Microgravity processing suppressed buoyancy-driven convection, preserving uniform nanoscale distribution of MXene nanosheets. Microgravity samples exhibited: (i) enhanced turbostratic carbon (002) ordering, (ii) heterogeneous nucleation and crystallization of quartz (101) exclusively upon MXene addition with intensity amplified by uniform MXene distribution, and (iii) superior cristobalite (SiO₂) crystallization following 1000 °C oxidation. Isothermal oxidation at 1000 °C demonstrated microgravity-processed 1wt% MXene-SiOC composites exhibit significantly lower mass gain compared to Earth-processed counterparts, attributed to: (1) uniform MXene-derived Ti atoms catalyzing cristobalite formation and strengthening the silica scale via Ti–O–Si bonding, and (2) retarded oxygen transport kinetics from stagnant thermal boundary layers suppressing rapid carbon combustion and enabling homogeneous SiO₂ scale development. |