Porcelain tiles are ceramic tiles commonly used to cover floors and walls, with a water absorption rate of less than 0.5 percent. They can either be glazed or unglazed. Porcelain tiles are one type of Vitrified tiles. So it falls in Vitrified tiles category, sometime it referred as Porcelain Vitrified Tiles.
Although porcelain has been used for making tiles for many years, only modern production methods and quantities has made the porcelain tile available for the average householder in recent years.
Large-scale production of porcelain tile is undertaken in many countries, with the major producers being China, Italy, Spain and Turkey. There are also countries undertaking small-scale production, such as Australia and strong growth in Brazil.
The hardness of the tile can be rated from zero to five according to ISO 10545-7 (also, ASTM C1027) test for surface abrasion resistance of glazed tile, and this can be used to determine suitability for various end use conditions.
The dense, hard surface of porcelain has made polishing a viable alternative to a glazed surface. This means that a tile can be fired, then a polish cut into the surface, creating a shine without a glaze.
Porcelain is much harder than ordinary ceramic tiles and is usually selected, despite its higher price etc.porcelain can be used in dry areas such as wall murals,dadoes and less traffic zones.
Porcelain is denser and therefore heavier to handle than other ceramic tiles. For this reason, it is generally more expensive.Being harder,it is more difficult to cut and drill, which can hamper fitting and increase costs. Polished porcelain may need sealing, where ordinary glazed tiles do not.the glazed surface is coated with less than two microns. porcelain attracts stubborn stains and becomes brittle when contact with chlorinated water and acids.
Specialised cements are necessary for installation of porcelain tiles, and in the US specifications, are set by the Tile Council of America and supported by the Tile Contractors Association. Porcelain, being denser and heavier than ordinary ceramic tiles, needs a stronger adhesive to hold the weight on walls. Therefore typical ready-mix adhesives are not recommended for porcelain.
When porcelain is first made, it is not absorbent, but the polishing process for making the unglazed surface shiny cuts into the surface, leaving it more porous and prone to absorbing stains, in the same way as natural stone tiles. Unless they have a suitable, long-lasting treatment applied by the manufacturer (for example, nanotech treatment), polished porcelain tiles will need sealing. Porcelain sealants are either solvent-based or water-based, which is cheaper, but does not last.