Method for treating metallic or ceramic surfaces at high temperatures

A method for treating metallic or ceramic surfaces, which comprises applying a lubricating composition comprising

• 50% by weight or more of a polyalkylene glycol or derivative thereof thermally decomposable at 150.degree. C. or above in air and
• 50% by weight or less of at least one fluorine containing compound selected from the group consisting of
• (b-1) nonionic fluorine-containing compounds having a fluoroalkyl group of 3 to 20 carbon atoms and a polyoxyalkylene chain,
• (b-2) compounds having a fluoroalkyl group of 3 to 20 carbon atoms and a residue of a carboxylic acid or a salt thereof with a metallic atom, ammonia or a nitrogen-containing amino compound capable of forming the salt with the carboxylic acid group in the molecule,
• (b-3) compounds having a fluoroalkyl group of 3 to 20 carbon atoms and a residue of phosphoric acid or a salt thereof with a metallic atom, ammonia or a nitrogen-containing amino compound capable of forming the salt with the phosphoric acid group in the molecule,
• (b-4) compounds having a fluoroalkyl group of 3 to 20 carbon atoms and a residue of sulfonic acid or a salt thereof with a metallic atom, ammonia or a nitrogen-containing amino compound capable of forming the salt with the sulfonic acid group in the molecule,
• (b-5) compounds having a fluoroalkyl groups of 3 to 20 carbon atoms and a cationic group containing a quaternary nitrogen atom in the molecule, and
• (b-6) compounds having a fluoroalkyl group of 3 to 20 carbon atoms and an amphoteric group in the molecule
• to the metallic or ceramic surfaces kept at 200.degree. C. or above, and treating the metallic or ceramic surfaces while thermally decomposing the component positively on the metallic or ceramic surfaces and converting the lubricating composition into a slightly sticking and piling up sludge consisting of a complex of the formed decomposition product with the component.