Method for making a coated stainless steel implant

A method for making a coated stainless steel implant, comprising:

• mixing metakaolin with an aqueous solution of NaOH to form a first mixture;
• mixing silica gel and silver nitrate with the first mixture to form a second mixture;
• mixing ZSM-5 zeolite with the second mixture to form a third mixture;
• and
• hydrothermally treating a stainless-steel substrate with the third mixture to form a silver-silicalite coating on the surface of the stainless-steel substrate thereby forming the coated stainless steel implant,
• wherein the hydrothermal treatment includes suspending the stainless-steel substrate in the third mixture by a wire, heating the stainless-steel substrate in the third mixture at a temperature range of 120 to 220° C. and sequentially pressuring to a pressure of up to 5 MPa and depressuring to ambient pressure,
• wherein the silver-silicalite coating comprises rhombohedral cuboidal particles having an average length of 2 to 5 μm, an average width of 1 to 2 μm and an average height of 0.5 to 2 μm,
• wherein the hydrothermal treatment is carried out in the absence of an organic template.