The bending of green tile is common during glazing process.
Excessive deformation frequently happens during tile glazing, and it is caused by the decorating machine which sometimes imposes such high deformation on the raw tiles to sometimes lead to the breaking of the material.
The study of deformation after firing of glazed ceramic materials detect the state of tension between the ceramic bodies and its decoration (engobe, glaze)
This study takes advatge of both the Optical Dilatometer and the Optical Fleximeter.
Pyroplasticity is the material tendency to deform under its own weight, due to a low viscosity during firing.
The measurement of pyroplasticity is particularly important for ceramic bodies that have to be completely sintered, because during the final stage of firing they develop an abundant vitreous phase with a sufficiently low viscosity to cause rapid deformation of the material.
It is really important to study the behaviour fo glazed tiles during their firing. Indeed, both the engobe and the glaze can affect the sintering process.
This plot shows how the enamel application on the ceramic body changes its own behaviour.