A composite thermal barrier coating (TBC) may be applied to a surface of components within an internal combustion engine. The composite TBC provides low thermal conductivity and low heat capacity insulation that is sealed against combustion gasses. The composite TBC includes three layers, bonded to one another, i.e., a first (bonding) layer, a second (insulating) layer, and a third (sealing) layer. The insulating layer is disposed between the bonding layer and the sealing layer. The bonding layer is bonded to the component and to the insulating layer. The insulating layer includes hollow microspheres that are sintered together to form insulation that provides a low effective thermal conductivity and low effective heat capacity. The sealing layer is a thin film that is configured to resist the high temperatures, present within the engine. The sealing layer is impermeable to gasses and presents a smooth surface.