TITANIUM NITRIDE-BASED LOW-EMISSIVE COATINGS - A STABILITY COMPARISON

Accelerated degradation tests with respect to high temperature and acid exposure have been performed with laboratory samples of TiO2/TiN/TiO2 transparent low-emissive coatings. The same tests have also been performed with noble metal-based low-emissive coatings presently marketed for energy conservation and solar control. The comparison clearly demonstrates the improvement in stability which is obtained when the soft, diffusive noble metal is replaced with a hard, high temperature stable transition metal compound. Using optical multilayer calculations to stimulate the effects of high temperature degradation, clear differences between the degradation mechanisms were identified: The TiN multilayer degrades by successive oxidation while the silver multilayer degrades by diffusion and agglomeration of the entire silver film.