SINGLE-CRYSTAL PARTIALLY STABILIZED ZIRCONIA AND HAFNIA CERAMIC MATERIALS

• Main Author: RICE, ROY W
• Format: Patent
• Language: English; French; German
• Published: 04.05.1983
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; CHEMISTRY; CRYSTAL GROWTH; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

Procede de fabrication d'un monocristal de bioxyde de zirconium ou de bioxyde d'hafnium partiellement stabilise en melangeant du bioxyde de zirconium ou du bioxyde d'hafnium en poudre avec 2 a 7 moles% d'un agent de stabilisation, tel qu'un oxyde soit d'un metal de transition soit d'un element de terre rare, en chauffant ce melange jusqu'a son etat de fusion et en refroidissant le melange en le retirant de la zone de chauffage a une vitesse de 2-30mm/heure. Les cristaux obtenus comprennent une matrice de materiau cubique cristallin et de nombreux materiaux cristallins minuscules tetragones et eventuellement monocliniques. De tels cristaux peuvent etre produits avec une resistance a la flexion d'environ 200.000 psi et une resistance a la cassure d'environ 7,85 Ksc. A method of making a single crystal of partially stabilized zirconium dioxide or hafnium dioxide by: mixing powdered zirconium dioxide or hafnium dioxide with 2 to 7 mole percent of a stabilizing agent, such as an oxide of either a transition metal or a rare earth element; heating the above mixture until it melts; and cooling the mixture by withdrawing it from the heating zone at a rate of 2-30mm. per hour. The resulting crystals comprise a matrix of cubic crystalline materials and numerous minute tetragonal and possibly monoclinic crystalline materials. Such crystals can be created having a flexure strength of approximately 200,000 psi and a fracture toughness of approximately 7,85 Ksc.