The invention concerns to the use of a powder comprising 99.95 to 95% of at least one polyamide and 0.05 to 5% of at least one silane for coating metals. This powder may be prepared by simple dry blending of the constituents. The silane can also be added to the molten polyamide in a mixing device and the resulting product reduced to powder. The addition of silane makes it possible to significantly improve electrostatic application by preventing a substantial portion of the powder from falling off during the electrostatic discharge which follows application, while providing lasting adhesion between the coating and metal. Advantageously, the silane is chosen from aminopropyltriethoxysilane and aminopropyltrimethoxysilane. The invention also concerns a method of coating an object with a film resulting from melting a thin layer of the powder.