Ageing resistance of SiBCN ceramics

Amorphous SiBCN alloys are known – depending on the elemental composition – for their thermal stability and high-temperature (up to 1500 °C) oxidation resistance, hardness, optical transparency or electrical and/or thermal conductivity. The paper reports ageing of SiBCN ceramics prepared in the form of thin films in a wide range of elemental compositions and preparation conditions. I focus on the room-temperature oxidation resistance, expressed in terms of the thickness and properties of the surface oxide layer 12 years since the deposition. I identify which compositions exhibit perfect long-time room-temperature oxidation resistance (this includes those, but not only those, which exhibit short-time high-temperature oxidation resistance) and which do not. For the latter I discuss the complex relationships between the characteristics of the surface oxide layer, the elemental composition of the films and the ion bombardment during the film growth. The results are important for tailoring long-lifetime ceramics combining the aforementioned functional properties.