Development of translucent ceramic tiles from modified porcelain stoneware tile paste

Abstract

In this work, a translucent ceramic was developed based on a porcelain stoneware paste modified by the addition of a frit to promote translucency. Six compositions were defined, with frit contents ranging between 20% and 50% (by mass). Alumina and quartz were also added at levels of up to 10% (by mass) to provide greater stability to the compacts during the firing process. The raw materials were characterised using X-ray fluorescence (XRF), and the standard translucent formulation (STD) was characterised using X-ray diffraction (XRD). The optical behaviour of the fabricated samples was analysed using spectrophotometric measurements (CIELab method). Samples of composition C06 (which included quartz) exhibited superior translucency. Thus, samples of the C06 formulation were subsequently prepared and characterised according to technical standards for the finished product, as well as for reflectance, transmittance, and microstructure using scanning electron microscopy (SEM). The characterisation results of the C06 sample indicate that it behaved similarly to the STD sample but exhibited superior stain resistance. The reflectance spectrum of the C06 sample was, on average, 10% lower than that of the STD sample. The transmittance as a function of wavelength (400–700 nm) was 2% lower for the C06 sample, reaching values of up to 12% for the STD sample. The colorimetric analysis showed that the C06 composition had a colour close to white, with a difference of 3.8% in the colorimetric parameter L* relative to that of the STD sample. The results also indicate that the C06 composition, contained added frit, showed adequate translucency for various applications, including the production of ceramic tiles for wall cladding. In fact, finished product tests performed showed that the flexural strength (σf) was 50.12 MPa and the water absorption was 0.02%. These flexural strength and water absorption values are within the limits typically required for wall cladding ceramics.