Abstract: An article having a substrate is protected by a thermal barrier coating system. An interfacial layer contacts the upper surface of the substrate. The interfacial layer may comprise a bond coat only, or a bond coat and an overlay coat. The interfacial layer has on its upper surface a preselected, controllable pattern of three-dimensional features, such as grooves in a parallel array or in two angularly offset arrays. The features are formed by an ablation process using an ultraviolet laser such as an excimer laser. A ceramic thermal barrier coating is deposited over the pattern of features on the upper surface of the interfacial layer.

Abstract: An article coated with a thermal barrier coating system for high temperature use, has its thermal cyclic spallation life improved by the application of an aluminide to the outer portion of a bonding coating disposed on a substrate. The bond coating has a surface roughness in the range of about 200-600 microinches Ra prior to application of covering thermal barrier coating.

Abstract: An article is coated with a thermal barrier coating system to increase its thermal cyclic spallation life. A single layer bond coating is applied to the surface of the article to a surface roughness in the range of 200 to 600 microinches RA by low pressure plasma spraying of coarse MCrAlY alloy particles into the surface. A metal selected from aluminum and its alloys is applied to the bond coating by aluminiding and is diffused into the bond coating to provide an aluminum-rich bond coating metal outer surface, while substantially retaining the surface roughness of about 2300 to 600 microinches RA. A metal oxide thermal barrier coating layer is then applied onto the aluminum-rich bond coating outer surface.

Abstract: A system is described for precise monitoring and control of the carbon content of the atmosphere of a furnace such as a carburizer used in the heat-processing of steel parts. The disclosed apparatus includes a sampling system for withdrawing a gas sample from the atmosphere within a furnace and an analyzer for producing signals indicative of the partial pressures of at least two gaseous components such as carbon dioxide and carbon monoxide. The analyzer preferably utilizes selective absorption of narrow-band infrared radiation signals in determining these signals. A processor combines the signals indicative of partial pressures with parameters obtained from measurements of furnace temperature, and calculates carbon potential of the furnace atmosphere. The processor output is coupled with an atmosphere control which maintains desired levels of carbon potential in the atmosphere of the furnace by, for example, regulating the flow of an enriching gas to the furnace.