The effect of bond coat composition on oxidation behavior of basalt base glass and glass-ceramics

In the current study, the effect of bond coat composition and single versus double layers on the interfacial properties of basalt glass-based coatings were investigated. Two bond coats, Ni-5 wt.% Al (METCO 450 NS) and Ni-Cr-6 wt.% Al (Metco 443 NS) were atmospheric plasma sprayed (APS) onto a commercial AISI 1040 steel substrate. These bond coating powders were used to observe the effect of a bond layer and multiple bond layers on certain mechanical properties, bonding strength and oxidation behaviour. Basalt was melted in a platinum crucible at 1500 degrees C for 1 h and cast into water. Basalt glass granules were ground and employed as a coating powder. After the APS process, amorphous coating layers were transformed to crystalline glass-ceramic with a heat treatment process. X-ray diffraction analysis (XRD) was used for glass-ceramic transformation and phase analysis. Scanning electron microscopy (SEM) examinations revealed that there is a uniform coating layer at the macroscopic scale. Cohesive bonding is dominant for both single and double bond-layered samples. It has been observed that the percentage of cohesive strength was approximately three to five times higher than that of the adhesion strength. (C) 2013 Elsevier B.V. All rights reserved.