Barter is the present and the future of international trade, especially for people who is starting in the import export business. Barter and more: Triangular operations.
Chemical surface treatment: blue and black, phosphating, pickling, electroless plating of various metals and alloys, TD treatment, QPQ treatment, chemical oxidation, etc.
Electrochemical surface treatment: anodic oxidation, electrochemical polishing, electroplating, etc.
Modern surface treatment: chemical vapor deposition CVD, physical vapor deposition PVD, ion implantation, ion plating, laser surface treatment, etc.