The invention relates to a part made of silicon-based ceramic material or silicon-based ceramic matrix composite (CMC) material comprising an environmental barrier coating (EBC), said coating (12, 13) comprising a bonding layer (12) deposited on the surface of the ceramic material or ceramic matrix composite (CMC), said bonding layer (12) being topped by one or more layers together forming a multifunctional barrier structure (13), characterised in that the bonding layer (12) has at its interface with the multifunctional structure a polycrystalline silica layer (12) or sub-layer (12b).

The invention relates to a part made of silicon-based ceramic material or silicon-based ceramic matrix composite (CMC) material comprising an environmental barrier coating (EBC), said coating (12, 13) comprising a bonding layer (12) deposited on the surface of the ceramic material or ceramic matrix composite (CMC), said bonding layer (12) being topped by one or more layers together forming a multifunctional barrier structure (13), characterised in that the bonding layer (12) has at its interface with the multifunctional structure a polycrystalline silica layer (12) or sub-layer (12b).

Artificial stone having excellent mechanical and weatherability properties is prepared from a highly filled crosslinkable organosilicon composition where the filler comprises at least 20 weight percent of coarse fillers, the organosilicon component contains silicon-bonded alkoxy and or hydroxyl groups, with a catalyst containing a metal compound and an amidine or guanidine.

Artificial stone having excellent mechanical and weatherability properties is prepared from a highly filled crosslinkable organosilicon composition where the filler comprises at least 20 weight percent of coarse fillers, the organosilicon component contains silicon-bonded alkoxy and or hydroxyl groups, with a catalyst containing a metal compound and an amidine or guanidine.