Process for joining alumina ceramic bodies

US5954900A · kind A · utility

Assignee

• ENVEC Mess- und Regeltechnik GmbH + Co. · DE

Inventors

• Frank Hegner · Bad Kötzting, DE
• Elke Schmidt · Bad Säckingen, DE
• Andreas Rossberg · Bad Säckingen, DE
• Bärbel Voigtsberger · Bad Klosterlausnitz, DE
• Ingolf Voigt · Jena, DE
• Henry Ludwig · Fullerton, US

Key dates

• Filing date: Sep 23, 1997
• Grant date: Sep 21, 1999
• Expiry date: Sep 23, 2017

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B2237/343
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

This process serves to form a long-time-vacuum-tight, high-strength, and corrosion-resistant joint, by means of a joining material, between a first body and a second body each made of sintered, polycrystalline alumina ceramic with a purity greater than 92 wt. % or of sapphire. The joining material is interposed in the form of a paste, a foil, or a slip between the first body and the second body. The joining material has been made from 1) an agglomerate-free, highly disperse, high-purity .alpha.-alumina powder with particles of as high a degree of calcination as possible and of a size not exceeding 100 nm (=10.sup.-7 m), 2) an anorganic oxidic powder of an auxiliary sintering agent with particles of approximately the same size as the particle size of the .alpha.-alumina powder, 3) an organic vehicle which is dissolved or suspended in an organic or aqueous solvant and in which the particles of the respective powder are distributed as evenly as possible. Instead of the anorganic oxidic powder of an auxiliary sintering agent an anorganic oxidic auxiliary sintering agent produced chemically as envelopes around or attachment to the particles of the .alpha.-alumina powder can be used, the…