Abstract: The present invention provides a method of manufacturing an abradable section to be formed on the interior of the casing of a gas turbine engine. The abradable section is formed by an additive manufacturing process to be of a lower density than the surrounding portions of the casing, but integrally formed with those portions. The abradable section thus formed can result in reduced blade fin tip wear, and may also have an improved performance. It may also have lower manufacturing costs. Formation of cooling passages in the abradable section is also easier and a wider range of designs of cooling passages can be provided. A gas turbine engine included such a casing is also provided.

Abstract: A method of assessing the degradation of an oxide-forming coating on a component after a period of operational use of the component, said degradation of the coating being caused by depletion of the oxide-forming element within a remnant coating layer due to inter-diffusion of said element between the remnant coating and both an outer oxide layer and an inner, secondary diffusion layer, wherein a depletion parameter indicative of the depletion of the oxide-forming element in the remnant coating layer varies as a function of the surface roughness of the coated component, the method comprising the steps of: carrying out a non-destructive, quantitative measurement of the surface roughness of the component after said period of operational use; and, based on an estimation of the functional relationship between the surface roughness and the depletion parameter, using the result of said measurement of surface roughness to quantitatively assess the degradation of the coating.

Abstract: A method of assessing the degradation of an oxide-forming coating on a component after a period of operational use of the component, said degradation of the coating being caused by depletion of the oxide-forming element within a remnant coating layer due to inter-diffusion of said element between the remnant coating and both an outer oxide layer and an inner, secondary diffusion layer, wherein a depletion parameter indicative of the depletion of the oxide-forming element in the remnant coating layer varies as a function of the surface roughness of the coated component, the method comprising the steps of: carrying out a non-destructive, quantitative measurement of the surface roughness of the component after said period of operational use; and, based on an estimation of the functional relationship between the surface roughness and the depletion parameter, using the result of said measurement of surface roughness to quantitatively assess the degradation of the coating.