Al2O3 protective coatings on carbon fiber-based 3D-textile preforms prepared by ALD for application in metallic composite materials

Carbon fiber-reinforced aluminum matrix composites (CF/Al-MMC) offer favorable properties and high design flexibility for lightweight applications. Nevertheless, poor wettability of carbon fibers by liquid aluminum alloys and high reactivity of carbon with liquid aluminum hinder a further development and limit the industrial application. To overcome these limitations an alumina protective coating is applied by atomic layer deposition (ALD) on carbon fiber-based 3D-textile. The deposition is carried out at a substrate temperature of 220°C using the precursors trimethylaluminum (TMA) and ozone. SEM analysis revealed a conformal and uniform coating (34±3 nm) with good adhesion to the fibers. Only a slight tensile strength reduction from 3.95 GPa to 3.20 GPa was observed due to coa ting. TGA demonstrated the significant improvement of oxidation resistance of carbon fibers by an alumina coating. Alumina coated carbon fiber-based 3D-textile preforms are infiltrated with AlSiCu alloy.