Enhanced thermal stability of Mo film with low infrared emissivity by a TiN barrier layer

The infrared reflective layer is one of the most important components of solar selective absorbing coatings (SSACs). The low infrared emissivity of the infrared reflective layer is necessary to reduce the energy losses caused by the thermal radiation from the SSACs. Also, the thermal stability of the infrared reflective layer has a crucial impact on the thermal stability of the entire coatings. In this study, a series of Mo films, as the infrared reflective layer, were deposited on stainless steel (SS) or glass substrates by DC magnetron sputtering. The effects of sputtering parameters on crystal structure, surface morphologies, film resistivity, and infrared emissivity of the Mo films are systematically investigated. The lowest infrared emissivity of the prepared Mo films is 0.06, which can be obtained by optimizing the deposition parameters. And the emissivity could be further decreased to 0.03 by annealing treatment. The insertion of a TiN layer between the Mo layer and the SS substrate can effectively inhibit the elemental diffusion from the SS substrate to the Mo film in vacuum until 700 degrees C, which improves effectively the operating temperature of the Mo film as an infrared reflective layer in SSAC.