Ceramic Matrix Composite Cyclic Ablation Behavior under Oxyacetylene Torch.

Area of Science:

• Materials Science
• Ceramic Composites

Background:

• Silicon carbide (SiC/SiC) composites are advanced materials for high-temperature applications.
• Understanding ablation behavior is crucial for their deployment in extreme environments.

Purpose of the Study:

• To investigate and compare the ablation properties of plain-woven SiC/SiC composites under single and cyclic ablation conditions.
• To analyze the microstructural changes and identify mechanisms responsible for material degradation and resistance.

Main Methods:

• Ablation tests were performed on plain-woven SiC/SiC composites using an oxyacetylene torch.
• Macro- and microstructural characterization techniques were employed to examine ablated surfaces and internal structures.

Main Results:

• Cyclic ablation resulted in a lower mass ablation rate but a higher linear ablation rate compared to single ablation.
• Surface analysis revealed white silica-rich oxide formation at the ablation center.
• Fibers in the central region showed layer-by-layer ablation with spiky morphology and attached silica particles.
• Molten oxides and silica particles contributed to ablation resistance.

Conclusions:

• The formation of protective oxide layers and the presence of molten silica particles mitigate ablation damage.
• Thermal shock, induced during cyclic ablation, leads to cracking in SiC/SiC composites.
• Findings provide insights for applying SiC/SiC composites in environments with complex thermal shock and ablation.