USE OF AN OXIDE CERAMIC MATERIAL FOR PRESSING TOOLS FOR SHAPING COMPONENTS MADE OF GLASS OR OF A GLASS-CONTAINING CERAMIC HAVING A HIGH SURFACE QUALITY AND DIMENSIONAL ACCURACY

摘要

The use of oxidized ceramic materials is disclosed for press tools for forming glass or ceramic elements containing glass having excellent surface finish and close tolerances. These are polycrystalline materials, single or multiple phase, inert in contact with the optical components to be pressed and which are also characterized by mechanical and thermal properties significantly superior to those of monocrystalline substances, whose behavior is essentially anisotropic due to of their geometric anisotropy. The material provided for the application envisaged by the invention may consist of an Al2O3 ceramic or a ceramic containing ZrO2 and / or HfO2. The material can also be produced as a multiphase material, that is to say it can contain a matrix component and at least one particulate component discretely dispersed in said matrix. Ceramics containing ZrO2, ZTC, PSZ or TZP, which have remarkable thermomechanical characteristics for the applications envisaged by the invention, due to the chemistry and especially the crystallography of their constituents, are preferably envisaged. To this end, mechanisms such as, for example, "stress transformation reinforcement" and "microcrack reinforcement" play an important role. The use of the materials concerned makes it possible to produce press tools for the forming, without reworking, of optical elements having flat and / or spherical and / aspherical convex and / concave surfaces, with a high surface finish. quality and high dimensional accuracy; at the same time improvements in manufacturing processes are obtained.