System and method for surface hardening of refractory metals

An object, comprising:

• a) an inner region which contains zirconium or a zirconium based alloy that is 98-100% pure zirconium and 0-2% trace impurities;
• and carbon;
• b) an outer region, adjacent to and outside said inner region, which contains zirconium or a zirconium based alloy that is 98-100% pure zirconium and 0-2% trace impurities, said outer region consisting of carbides of metals in the inner body;
• wherein said outer region comprises a lattice having said outer region, said outer region being formed such that a crystal structure of said zirconium or said zirconium based alloy in both said inner region and said outer region has not changed as a result of said carbon being diffused therein and wherein said carbon is diffused in said lattice of said outer region without co-diffusion of oxygen, hydrogen or sulfur as contaminants;
• said inner region has no carbon levels above the trace elements found in said zirconium or said zirconium based alloy and has a hardness that is less than a hardness of said outer region and is integral with said outer region;
• said outer region of a phase of carbides of said zirconium or said zirconium based alloy having a thickness of between 5 to 100 microns.