Real-time quantitative imaging of RTV silicone pyrolysis

TL;DR

This study employs in situ high-temperature X-ray micro-tomography to quantitatively analyze the microstructural evolution of RTV silicone during pyrolysis, revealing heating rate-dependent changes crucial for modeling thermal responses.

Contribution

It introduces a real-time, high-resolution imaging method to analyze RTV silicone pyrolysis microstructure evolution, enabling detailed quantitative assessment.

Findings

Microstructure resolution below 5 micrometers per pixel.

Porosity and pore network size depend on heating rate.

Densification observed through X-ray attenuation.

Abstract

Quantitative microstructural analysis of Room Temperature Vulcanized (RTV) silicone pyrolysis at high temperatures is presented. RTV is used as a bonding agent in multiple industries, particularly filling gaps in ablative tiles for hypersonic (re-)entry vehicles and fire prevention. Decomposition of RTV is resolved in real time using in situ high-temperature X-ray computed micro-tomography. Full tomographies are acquired every 90~seconds for four different linear heating rates ranging from 7 to 54 C/min. The microstructure is resolved below 5 micro-meters/pixel, allowing for a full quantitative analysis of the micro-structural evolution and porous network development. Results are highly heating rate dependent, and are evaluated for bulk sample volume change, porosity, pore network size, and observed densification from X-ray attenuation. The outcome of this work is critical to develop multi-physics models for thermal response.