Influence of bubble structure on adherence and chemical durability of porcelain enamel

The aim of this research was to evaluate the relationship between bubble structure and the physicochemical properties of porcelain enamels. To better understand this relationship, two basic different compositions were examined by chemical durability and adherence test. Two formulations were considered, cobalt containing enamel (CCE) and cobalt free enamel (CFE). Bubbling microstructure of enamels was studied using optical and scanning electron microscopy (SEM) along with energy dispersive spectroscopy (EDS) analysis. Also, enamel adherence strength, chemical durability and corrosion mechanisms were explained by the remains of the enamel on the destroyed surface and by Fourier transform infrared reflectance (FTIR) respectively. The results showed that the CCE composition had a coarser bubble structure than the CFE one and exhibited better adherence properties. In addition, the chemical durability test showed that CFE had a higher chemical resistance. The major corrosion mechanism in CFE was detected as dissolution of the glass network while in CCE it was ion exchange.