The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 21, 1999
Filed:
Sep. 23, 1997
Frank Hegner, Lorrach, DE;
Elke Maria Schmidt, Schopfheim, DE;
Andreas Rossberg, Bad Sackingen, DE;
Barbel Voigtsberger, Bad Klosterlausnitz, DE;
Ingolf Voigt, Jena, DE;
Henry Ludwig, Gera, DE;
ENVEC Mess- und Regeltechnik GmbH + Co., Weil am Rhein, DE;
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 total .alpha.-alumina and auxiliary-sintering-agent content of the paste, the foil, or the slip ranging between 50% and 70%. After interposing the joining material the bodies are heated to a temperature of not more than 1,300.degree. C. and then allowing them to cool down.