Method of producing a protective layer on a structural part

摘要

A method for the production of a protective layer on a structural part against thermal, chemical and/or mechanical stresses, particularly structural parts of complex shape such as turbine blades in which powder of a starting material for the layer is suspended in a suspension liquid and the suspension is held at a temperature just above the freezing point of the suspension. The structural part to be coated is maintained at a temperature below the freezing point of the dispersing liquid and is dipped into the suspension so that a layer of the powder present in the suspension freezes firmly on the part. The thickness of the layer is dependent on the temperature of the structural part and the length of time during which the structural part remains immersed on the suspension. The structural part now coated with the powder layer is subjected to freeze drying and is thereafter heated to a temperature above the freezing point of the suspension.