Influence of composition on mechanical behaviour of porcelain tile. Part III: Effect of the cooling rate of the firing cycle

▶ Macroscopic residual stresses up to 34 MPa were produced by quenching. ▶ Quenching also produced increasing on flaw size from virtually 0 up to 174 μm. ▶ Some compositions have increased bending strength closely to residual stresses value. ▶ Mullite protected the microstructure against crack grows on cooling.