CrTaN coatings were fabricated using reactive direct current magnetron co-sputtering on a Ti interlayer covering silicon substrates with various bias voltages. The CrTaN coatings were annealed at 600 degrees C for 4-24 h under a 50 ppm O-2-N-2 atmosphere, and the effectiveness of the fabricated layers as a protective coating for glass molding dies was assessed. The effects of biased voltage on the structure, mechanical properties, surface roughness values, and oxygen diffusion depths were investigated. The results indicated that the coating prepared with a bias voltage of -25 V exhibited mechanical properties that were superior to those of the other coatings used in this study. In addition, these properties (including nanohardness, Young's modulus, and the derivative H-3/E-2 ratio) increase after annealing at 600 degrees C in a glass molding atmosphere (i.e., 50 ppm O-2-N-2 atmosphere, with a smoother surface characteristic). (C) 2012 Elsevier B.V. All rights reserved.