A coated seal slot system for turbomachinery includes a first turbine component comprising a first groove having at least one first coating attached to at least a portion of the first groove of the first turbine component, a second turbine component comprising a second groove having at least one second coating attached to at least a portion of the second groove of the second turbine component. The first and the second turbine components are disposable adjacent to each other with the first groove having the first coating and the second groove having the second coating together forming a coated seal slot extending across a gap between the first turbine component and the second turbine component. A seal is disposable in the coated seal slot and extendable across the gap between the first and the second turbine components and engageable with the first coating and the second coating to inhibit leakage of gas through the gap.