Fabrication of ceramic coatings from polysilazane/aluminum: Effect of aluminum content on chemical composition, microstructure, and mechanical properties

Ceramic coatings with a thickness range of 1.5–5.5 μm were successfully prepared with polysilazane (PSN1) as a precursor and aluminum (Al) powder as an active filler. The effect of Al content on chemical composition, microstructure, and mechanical properties of the coatings was investigated. Chemical composition analysis revealed that Al powder was completely converted into Al2OC and AlN phases during the ceramization process, accompanied by volume expansion. Ceramic coatings derived from less Al powder containing PSN1/Al showed more compacted surface morphology and continuous microstructure. The surface hardness and elastic modulus of ceramic coatings decreased with the increase of the volume fraction of Al from 10% to 40% (Al/PSN1, v/v). The maximum surface hardness and elastic modulus of coatings were 6.38 GPa and 107.66 GPa, respectively.