A coating having a gradient composite structure, applied to a substrate, which may be a disposable tool. The gradient composite comprises a bonding component and an erosion and/or corrosion resistant component. When applied to a disposable tool, such as a ball and seat assembly in a downhole environment, the coating enhances the performance of disintegrable materials used in such tools. The coating may be configured to expire at the end of a selected duration, allowing the underlying material to disintegrate.