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 NiCr-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 °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.