Abstract: A coating and method for overcoating a TBC on a component used in a high-temperature environment, such as the combustor section of an industrial gas turbine. The coating defines the outermost surface of the component and is formed of at least two layers having different compositions. An inner layer of the coating contains alumina in a first silica-containing matrix material that is free of zinc titanate. An outer layer of the coating contains alumina, a glass material, and zinc titanate in a second silica-containing matrix material. The outer layer of the coating has a surface roughness of not greater than three micrometers Ra and forms the outermost surface of the component. The coating reduces the component temperature by reducing the convective and radiant heat transfer thereto.

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.

Abstract: A differential thickness pattern can be induced in a coating that is sprayed on an aircraft engine part using a robotic system. The robotic system includes a spray mechanism with a triggering device to spray the coating on the aircraft engine part and a controller. The controller is used to move the spray mechanism along a predetermined path and to activate and deactivate the triggering device. To obtain the differential thickness pattern, a predetermined profile of the aircraft engine part corresponding to areas of the aircraft engine part requiring a thicker coating is integrated into a control program used by the controller. The controller uses the control program to activate and deactivate the triggering mechanism to limit the spraying of the coating to only those areas of the part in the predetermined profile to obtain a different coating thickness.

Abstract: A differential thickness pattern can be induced in a coating that is sprayed on an aircraft engine part using a robotic system. The robotic system includes a spray mechanism with a triggering device to spray the coating on the aircraft engine part and a controller. The controller is used to move the spray mechanism along a predetermined path and to activate and deactivate the triggering device. To obtain the differential thickness pattern, a predetermined profile of the aircraft engine part corresponding to areas of the aircraft engine part requiring a thicker coating is integrated into a control program used by the controller. The controller uses the control program to activate and deactivate the triggering mechanism to limit the spraying of the coating to only those areas of the part in the predetermined profile to obtain a different coating thickness.