Process for coating a surface of a substrate made of nonmetallic material with a metal layer

A process for coating a surface of a substrate made of nonmetallic material with a metal layer, characterized in that it consists of the following steps:

• a) a substrate made of nonmetallic material is provided;
• b) at least part of at least one surface of said substrate is subjected to a physical or chemical treatment for increasing the specific surface area thereof;
• c) that surface of said substrate which was treated in step b) is subjected to an oxidizing treatment;
• d) that surface of said substrate which was treated in step c) is brought into contact with a solution containing at least one ion of at least one metal and its counterion, said metal being chosen from the group constituted of the metals of groups IB and VIII of the Periodic Table of the Elements;
• e) a substrate comprising ions of at least one metal that are chemically attached to the nonmetallic material constituting the substrate on at least one part of at least one of its surfaces is obtained;
• f) said ions of at least one metal that are chemically attached to the nonmetallic material constituting the substrate on a surface of said substrate are subjected to a reducing treatment and a substrate comprising atoms of at least one metal that are chemically attached to the nonmetallic material constituting the substrate on at least one part of at least one of its surfaces is obtained;
• g) that surface comprising particles of at least one metal which was obtained in step f) is brought into contact with a solution containing ions of at least one metal;
• h) a coating formed by a layer of at least one metal is obtained on the treated surface of said substrate,
• said steps being optionally followed or preceded by one or more rinsing steps.