Fuegetechniken fuer hochbelastbare oxidkeramische Geraete- und Apparatebauteile. Teilprojekt Heraeus: Elektrodenherstellung Abschlussbericht

Abstract

The present subproject aimed on the improvement of the junction between platinum and ZrO_2-doped alumina in high-level service Pt electrodes for magnetic-inductive flowmeters. Five different approaches have been studied: 1. application of massive Pt metal or PtIr10 alloy; 2. coating of ceramical bodies with platinum containing ceramical dyes; 3. impregnation of ceramical bodies with hexachloro platinum acid; 4. application of Pt/oxide-ceramical composites with ceramics as the matrix, and 5. application of Pt/oxide-ceramical composites with platinum as the matrix. Only by method (5.) conductive cermet electrodes of high temperature resistance (1720 C) could be reproducibly obtained using a powder metallurgically prepared Pt-Al_2O_3 mixture. Parallel studies on the Pt-Zr-O system revealed the formation of an Haegg phase: the solubility of oxygen in Zr-doped Pt increases with increasing Zr content on account of the Pt host lattice expansion due to Zr substitution. (WEN)SIGLEAvailable from TIB Hannover: F96B75+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman