Abstract: A high emissivity (Hi-E) coating for use on the exhaust baffles of HIRSS systems. HIRSS systems were developed to reduce the infrared (IR) signature of helicopter engines. Increasing operating temperatures of helicopter engines have made the HIRSS systems less effective. An infrared coating applied over selected portions of the HIRSS reduces the IR of the system. The Hi-E coating comprises, in weight percent, 30-80% refractory oxide pigment, 5-20% binder, 1-15% potassium oxide, optionally up to about 15% glass-forming material and the balance refractory oxide powder. When applied to provide a surface finish of 1100Ra microinches or coarser, the coated HIRSS has a significantly reduced hemispherical reflectance in the IR frequency range.