Deposition and Properties of Amorphous TiBN/AlCrYNMultilayer Coatings with Various Modulation Periods

In this paper, multilayer coatings consisted of amorphous AlCrYN layers and TiBN layers were deposited by the cosputteringtechnique. The influence of the modulation period of the multilayer coatings on the structure, mechanical properties, andoxidation behavior of the coatings was studied carefully by using scanning electron microscope, X-ray diffraction,nanoindentation, scratch tester, and thermogravimetric analyzer. The results show that the TiBN/AlCrYN multilayer coatingsexhibit an amorphous structure without any feature. Decreasing the modulation period could significantly improve the coatinghardness and elastic modulus. In addition, the adhesion of the multilayer coatings could be enhanced as the modulation perioddecreases. At relative low oxidation temperature (≤900°C), a dense aluminum oxide layer formed on the coating surface caneffectively hinder the inward diffusion of O and the outward diffusion of metal elements. The oxidation behaviors of theTiBN/AlCrYN multilayer coatings obeyed the diffusion control law. The oxidation resistance of the coatings was increasing withdecreasing the modulation period since the interfaces of multilayer structures would block the diffusion of elements. At relativehigh oxidation temperature (1000°C), however, the coating surface was rapidly oxidized into the porous TiO2whiskers ratherthan the dense Al2O3layer, resulting in the inward diffusion of O and thus causing the serious oxidation of the coatings.