A part including a substrate in which at least a portion adjacent to a surface of the substrate is made of a refractory material containing silicon, is protected by an environmental barrier formed on the surface of the substrate and having at least a self-healing layer containing a rare earth silicate. The self-healing layer is formed: for at least 90 mol %, by a system constituted by 30 mol % to at most 80 mol % of at least one rare earth silicate RE.sub.2Si.sub.2O.sub.7, RE being a rare earth, and at least 20 mol % to 70 mol % of manganese oxide MnO; and for at most 10 mol %, by one or more oxides other than MnO, having a eutectic point with SiO2 less than or equal to 1595? C.; the self-healing layer presenting a liquid phase having a self-healing function at least throughout the temperature range 1200? C. to 1400? C., while conserving a majority solid phase.

Processes for incorporating phase change materials (PCM) into porous construction elements, composite construction elements produced thereby, and structures constructed therefrom. Such a process includes heating a PCM to a temperature at or above a melting temperature thereof to liquify the PCM and yield a liquid PCM, fully immersing a porous construction element in the liquid PCM, and infiltrating the liquid PCM into porosity of the construction element while the construction element and liquid PCM are at a subatmospheric pressure level and at a temperature sufficient to maintain the PCM in a liquid state to yield a composite construction element in which the porosity of the construction element has been at least partially filled with the PCM. Such a composite construction element is preferably capable of increasing the thermal inertia of a building envelope constructed therefrom with little or no detrimental effects on properties of the construction elements.

A method for protecting a coated substrate having a porous ceramic barrier coating includes applying a molten salt to the ceramic barrier coating. The salt is selected from the group consisting of one or more acetates and/or nitrates. The molten salt is infiltrated into porosity of the ceramic barrier coating. The infiltrated molten salt is solidified. The solidified salt is sintered.