PROCESS FOR INCREASING THE RESISTANCE OF A LITHIUM ALUMINO-SILICATE VITROCERAMIC BY SURFACE MODIFICATION, VITRO-CERAMIC OBTAINED ACCORDING TO SAID METHOD AND USE THEREOF

摘要

The present invention relates to a process for increasing the mechanical strength of a lithium alumino-silicate glass ceramic, in which the surface of the green glass is coated before cerating with a solution or a suspension of a lithium salt. or an organic compound capable of decomposing, during ceramization, to give a lithium salt, which lithium salt has a melting point of at least 720 degrees C, and then the coating thus obtained is dried, these coating and drying operations are repeated, if necessary, until the layer thus deposited on the surface of the glass contains from 10 to 5000 mg / m 2 of lithium ions, and the ceramic is converted into ceramic The invention also relates to a glass-ceramic obtained by this process, the surface of which has a better mechanical strength than that of the surface of a glass-ceramic produced without its surface having undergone a glass-ceramic exchange. The invention further relates to the use of such a glass-ceramic in hotplates.