Development and characterisation of a single-stage ceramic tile grout sealing process using a high power diode laser

The feasibility of using a 60 W high power diode laser (HPDL) to seal the void between adjoining ceramic tiles with a specially developed grout material has been demonstrated. A single-stage process has been devised which utilises a crushed tile mix to act as a tough, inexpensive bulk substrate and a glazed enamel surface to provide an impervious surface glaze. HPDL processing has resulted in crack and porosity free seals produced in normal atmospheric conditions. The single-stage grout is simple to formulate and easy to apply. Tiles were successfully sealed with power densities as low as 750 W/cm² and at rates of up to 600mm/min. Bonding of the enamel to the crushed ceramic tile mix was identified as being primarily due to van der Waals forces and, on a very small scale, some of the crushed ceramic tile mix material dissolving into the glaze. Optical inspection and water permeability tests revealed that a complete bond between the enamel glaze and the crushed ceramic tile mix, as well as between the enamel glaze and the vitrified surface of the ceramic tiles themselves, was achieved. The results of mechanical and chemical tests showed that the single-stage ceramic tile grout outperformed the conventional epoxy tile grout in all the test areas. Indeed, in many instances the performance of the single-stage ceramic tile grout approached, and occasionally surpassed, that of the ceramic tiles themselves. Life assessment testing revealed that the single-stage ceramic tile grout seals gave an increase in wear life of 4-42 times over conventional epoxy tile grout, depending upon the corrosive environment.