Preparation of innovative metallic composite glazes for porcelainized stoneware tiles

Innovative metallic glazes for porcelain stoneware tiles, containing stainless steel and a special Ni-based alloy (NiCoCrAlY, commonly used as bond coating material in thermal barrier coating systems on Turbogas superalloy components), have been studied. These new products, called “metallic composite glazes” (MCGs), showed different aesthetic properties than usual lustres or metallic glazes. After heating, the surfaces of these innovative glazes did not display any interesting behaviour, but, after polishing, a particular metallic aesthetic effect has been found. These new glazes can be described as composite materials made of a glass matrix reinforced with metal particulates. A deep characterisation of metallic powders and MCGs was performed by using several techniques. The glazes containing the NiCoCrAlY powders manifested the best aesthetic, microstructural, thermal and chemical properties.