Ceramic component having silicon layer and barrier layer

A gas turbine engine comprising:

• a compressor section;
• a combustor in fluid communication with the compressor section;
• and
• a turbine section in fluid communication with the combustor, and at least one sealing system in the turbine section or the combustor, the at least one sealing system including:
• a ceramic component having a surface region defining a first surface roughness,
• a metallic component situated adjacent the surface region, and
• a coating system disposed on the surface region, the coating system including a silicon-containing layer and a barrier layer, the silicon-containing layer disposed on the surface region, the barrier layer extending continuously around the ceramic component and the silicon-containing layer, the barrier layer having a first section disposed between the metallic component and silicon-containing layer, a second section disposed on the ceramic component, and an intermediate section that connects the first section and the second section, the first section having a surface in contact with the metallic component, the surface of the first section having a second surface roughness that is less than the first surface roughness, the barrier layer limiting interaction between silicon of the silicon-containing layer and elements of the metallic component, and the barrier layer having a coefficient of thermal expansion that is within 60% of a coefficient of thermal expansion of the ceramic component,
• wherein the barrier layer includes at least one of hafnon and zircon.