A two-stage ceramic tile grout sealing process using a high power diode laser - II. Mechanical, chemical and physical properties

Ceramic tiles sealed using a portable 60 Wcw high power diode laser (HPDL) and a specially developed grout material having an impermeable enamel surface glaze have been tested in order to determine the mechanical, chemical and physical characteristics of the seals. The work showed that the generation of the enamel surface glaze resulted in a seal with improved mechanical and chemical properties over conventional epoxy tile grouts. Both epoxy tile grout and laser generated enamel seals were tested for compressive strength, surface roughness, wear, water permeability and acid/alkali resistance. The enamel seal showed clear improvements in strength, roughness and wear, whilst being impermeable to water, and resistant (up to 80% concentration) to nitric acid, sodium hydroxide and detergent acids. The bond strength and the rupture strength of the enamel seal were also investigated, revealing that the enamel adhered to the new grout and the ceramic tiles with an average bond strength of 45-60 MPa, whilst the rupture strength was comparable with the ceramic tiles themselves. The average surface roughness of the seals and the tiles was 0.36 and 0.06 μm, respectively, whilst for the conventional epoxy grout the average surface roughness when polished was 3.83 μm and in excess of 30 μm without polishing. Life assessment testing revealed that the enamel seals had an increase in actual wear life of 2.9 to 30.4 times over conventional epoxy tile grout, depending upon the corrosive environment.