Cu74Ti25 alloy films were annealed in flowing NH3 at temperatures of 450 to 700 degrees C. Ti segregates to the free surface to form TiN, leaving nearly pure Cu in the remaining metal film. Elastic recoil detection and Auger electron spectroscopy were applied to investigate the chemistry of the as-formed nitride as a function of anneal temperature. The use of these two techniques in tandem offers a combination of standardless compositional determination, excellent mass and depth resolution, and chemical bonding information. The Ti:N ratio is nearly 1.0 for T greater than or equal to 550 degrees C, and the nitride contains similar to 6 atom percent O. The amount of nitrogen incorporated increases with temperature with an activation energy of 0.6 eV. A native Ti oxide remaining at the TiN/Cu interface suggests Ti is the dominant diffusing species during nitridation.