Abrasive coating for high-temperature mechanical systems

A system comprising:

• a stationary component comprising:
• a substrate;
• and
• an abradable layer on the substrate;
• and
• a rotating component comprising:
• a tip;
• and
• an abrasive coating system on the tip, wherein the abrasive coating system comprises:
• an oxide- or silicate-based barrier layer, and
• an abrasive top layer on the barrier layer, wherein the abrasive top layer is the only layer of the abrasive coating system that includes an abrasive material, the abrasive material comprising at least one of silicon carbide, molybdenum disilicide, or silicon nitride, wherein the abrasive top layer defines a thickness extending from a top surface of the abrasive top layer to a bottom layer interface of the abrasive top layer nearest the oxide- or silicate based barrier layer, wherein the abrasive top layer has a uniform composition along the thickness of the abrasive top layer,
• wherein the oxide- or silicate-based barrier layer comprises at least one of hafnon, hafnium oxide, a blend of hafnium oxide and silicon, a blend of hafnium oxide and silicon oxide, a rare earth silicate, BSAS, or stabilized hafnia,
• wherein the stationary component and the rotating component are configured so the abrasive coating system contacts a portion of the abradable layer during rotation of the rotating component, and wherein the abradable layer is configured to be abraded by the contact by the abrasive coating system.