The present invention relates to a method of covering a metal article with a film formed from the melting of a thin layer of powder comprising: physically blending 99.8 to 97% by weight of at least one polyamide and 0.2 to 3% by weight of an inorganic biocide species consisting of a soluble ceramic in which silver ions are encapsulated to form a powder blend composition; contacting said metal article with said powder composition blend to form a thin layer of said powder on the article; melting said powder blend composition onto said metal article to form a thin coating film; and cooling said coated article; where the powder blend composition is free of zinc compounds.