Potassium ion-exchange on surface of beta-spodumene

摘要

This invention relates to the strengthening of glass-ceramic articles wherein the crystal content thereof comprises the predominant portion and containing beta-spodumene solid solution as the principal crystal phase. The strengthening effect is accomplished through an ion exchange process taking place within a surface layer of the article such that potassium ions from an external source are exchanged for lithium ions in the crystal phase thereby causing compressive stresses to be set up in the surface layer.