The invention relates to a component (8) comprising a substrate made of chromia-former metal alloy (82), the basic element of which is iron (Fe) or nickel (Ni), wherein the substrate has two main planar faces. According to the invention: one of the main planar faces is coated with a coating comprising a thick layer of ceramic (80), grooved to delimit channels (800) suitable for the distribution and/or collection of gases, such as H2O water vapour, H2 or air, and/or one of the main planar faces is coated with a thick metal layer (81), grooved to delimit channels (810) suitable for the distribution and/or collection of gases, such as H2O water vapour, H2, O2 or draining gas. The invention also relates to the associated production processes.