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 optimising the design of a component is provided, in which a set of principal design variants is generated, the variants having design parameters which are common to all design variants of the set and some which differ between variants. Subsets of secondary design variants are generated by a computer executed rule based geometry engine, the subsets comprising at least one secondary design variant, generated by modifying at least one design parameter or design variable of the principal design variant.

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.