Endress + Hauser Gmbh + Co. Kg

Envec Mess- Und Regeltechnik Gmbh + Co.

Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Endress+hauserse+co. Kg

Henry Ludwig

Frank Hegner

Elke Maria Schmidt

Andreas Rossberg

Erhard Kemnitz

Ingolf Voigt

Andreas Roβberg

Barbel Voigtsberger

Andreas Roßberg

Frank Kastner

Uta Oberbach

Uwe Reichel

A method for manufacturing an elastic deformation body made of an AlOceramic according to which a highly pure alumina having at most 2000 ppm MgO, at most 200 ppm inorganic impurities, a specific surface of at least 10 m/g, an average grain size of at most 0.3 &#x3bc;m is applied. With the alumina and additives, there is produced via aqueous processing a homogeneous mixture, from which a pressable spray granulate is produced, which is formed by means of a uniaxial pressing method to a homogeneous, green body, which is subjected to a sinter process. The resulting elastic deformation body has a bending fracture stress &#x3c3;, whose distribution F(&#x3c3;) is given by the Weibull parameters &#x3c3;&#x2267;800 MPa and m&#x2267;24, with an average grain size of the sintered material of no more than 2 &#x3bc;m, and wherein the sintered material of the deformation body has a density of not less than 3.98 g/cm.

Method for manufacturing an elastic body of Al2O3 ceramic, measuring membrane for a pressure sensor and pressure sensor with such a membrane

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.

Process for joining alumina ceramic bodies

Growing community of inventors

Gera, Germany

Henry Ludwig