An improved mechanical face seal is provided which includes a pair of relatively rotatable seal rings having opposing seal faces. At least one of the seal faces and preferably the silicon carbide seal ring includes a tantalum coating over the seal face. The coating is formed such that the exposed seal face surface is formed of tantalum with a preferred thickness, and the substrate is the silicon carbide seal ring material. Between the silicon carbide substrate and exposed tantalum coating layer, an intermediate transformation layer of tantalum carbide is formed to enhance bonding of the substrate and coating layer. Preferably, the tantalum carbide layer is formed during the coating process wherein the tantalum is applied by chemical vapor deposition and the tantalum reacts with the silicon carbide to form the tantalum carbide at the interface between the tantalum coating layer and the seal ring substrate.