Crystalline carbon nitride/TiN composite coatings have been deposited using a dual‐cathode magnetron sputtering system onto polished silicon andM2 steel substrates held at room temperature. We propose that TiN provides a lattice‐matched structural template to seed the growth of carbon nitride crystallites. The resulting coatings are smooth, fully crystalline, with nanoindentation hardness in the range of 45–55 GPa. This hardness is in the low‐end range of diamond films. Suggestions for better seeding materials to further improve the hardness are proposed. ©1995 American Institute of Physics.