Coating effects on thermal properties of carbon carbon and carbon silicon carbide composites for space thermal protection systems

•CTE tests have been performed on coated and non coated samples.•CTE results have been compared in order to evaluate the thermal properties variations.•Matrix morphology (infiltration level) of composites strongly influences the thermal behavior, so, different manufacturer samples lead to different CTE values.•Coating, chosen for its compatibility with this kind of materials, modifies the thermal behavior making the material to have a better dimensional stability and so lower CTE values.•Morphological analysis has been performed in order to study the degradation of the material.