The role of surface microstructure on the resistance to stains of porcelain stoneware tiles

• Published in: Journal of the European Ceramic Society Vol. 25; no. 4; pp. 357 - 365
• Main Authors: Dondi, M., Ercolani, G., Guarini, G., Melandri, C., Raimondo, M., Rocha e Almendra, E., Tenorio Cavalcante, P.M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-04-2005; Elsevier
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Ceramic tiles; Chemical industry and chemicals; Exact sciences and technology; Heavyclay products, whiteware; Microstructure-final; Porcelain stoneware; Porosity; Stain resistance; Tiles; Microstructure-final; Porcelain stoneware; Porosity; Stain resistance; Tiles; Scanning electron microscopy; Stoneware; Tile; Polishing; Experimental study; Surface treatment; Surface structure; Porcelain; Surface defect; Surface properties; Property structure relationship; Microstructure; Ceramic materials
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2004.01.017

Porcelain stoneware tiles frequently undergo a polishing process, aimed at improving their aesthetical appearence, that brings about a consistent material removal, with formation of superficial defects and opening of closed pores. The consequent degradation of surface characteristics—and especially the increased sensitivity to stains—represent the main limit to the use of polished tiles in many indoor and outdoor applications. In order to better understand the role of microstructure on the resistance to stains, a phenomenological study of staining/cleaning operations (ISO 10545 parts 14 and 16) and a thoroughful physico-microstructural characterisation of tile working surfaces (SEM, open and closed porosity, rugosimetry, MIP) were carried out on twelve industrially manufactured and polished products. Diverse staining behaviours proved to be connected with different tile microstructures, being the surface roughness as well as the amount and shape of coarser pores the most influent variables. Through a statistical approach, an empirical predictional model of the amount of stain retained by the tile surface after mild washing with warm water was set up. It is based on roughness measurements (both
R
a and
R
t), estimation of macropores (i.e. 1–50
μm by MIP) and pore roundness (by image analysis of SEM photomicrographs).