title: High-performance and anti-stain coating for porcelain stoneware tiles based on nanostructured zirconium compounds.
abstract: The technological characteristics of porcelain stoneware tiles make them suitable for a wide range of applications spanning far beyond traditional uses. Due to the high density, porcelain stoneware tiles show high bending strength, wear resistance, surface hardness, and high fracture toughness. Nevertheless, despite being usually claimed as stain resistant, the surface porosity renders porcelain stoneware tiles vulnerable to dirt penetration with the formation of stains that can be very difficult to remove. In the present work, we report an innovative and versatile method to realize stain resistant porcelain stoneware tiles. The tile surface is treated by mixtures of nanosized zirconium hydroxide and nano- and micron-sized glass frits that thanks to the low particle dimension are able to penetrate inside the surface pores. The firing step leads to the formation of a glass matrix that can partially or totally close the surface porosity. As a result, the fired tiles become permanently stain resistant still preserving the original esthetical qualities of the original material. Treated tiles also show a remarkably enhanced hardness due to the inclusion of zirconium compounds in the glass coating.
authors.affiliation: Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, 50019 Sesto Fiorentino, Firenze, Italy.
authors.forename: Moira
authors.initials: M
authors.lastname: Ambrosi
authors.affiliation: Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, 50019 Sesto Fiorentino, Firenze, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Santoni
authors.affiliation: Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, 50019 Sesto Fiorentino, Firenze, Italy.
authors.forename: Rodorico
authors.initials: R
authors.lastname: Giorgi
authors.affiliation: Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, 50019 Sesto Fiorentino, Firenze, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Fratini
authors.affiliation: Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, 50019 Sesto Fiorentino, Firenze, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Toccafondi
authors.affiliation: Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, 50019 Sesto Fiorentino, Firenze, Italy. Electronic address: piero.baglioni@unifi.it.
authors.forename: Piero
authors.initials: P
authors.lastname: Baglioni
mesh_terms: D003776:Dental Porcelain / Q000737:chemistry*; D005898:Glass / Q000737:chemistry; D016062:Porosity; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003776:Dental Porcelain; D015040:Zirconium
keywords: Anti-stain materials; Ceramic coatings; Mechanical properties; Monoclinic nanoparticles of zirconia; Nanoparticles; Porcelain stoneware; Tetragonal nanoparticles of zirconia; Zircon; Zirconia