Ceramic pressure measurement cell and method for production thereof

US10330549B2 · kind B2 · utility

Assignee

• Endress+Hauser SE+Co. KG · DE

Inventors

• Nils Ponath · Lörrach, DE
• Andreas Rossberg · Bad Säckingen, DE

Key dates

• Filing date: Apr 22, 2014
• Grant date: Jun 25, 2019
• Expiry date: Dec 9, 2035

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B2237/62
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

A pressure measurement cell, comprising: a ceramic measurement membrane and a ceramic counterpart. The measurement membrane is joined to the counterpart in a pressure-tight manner forming a pressure chamber between the measurement membrane and the counterpart by means of an active brazing solder. The pressure measurement cell furthermore has a solder stop layer on a surface of the measurement membrane and/or the counterpart, wherein the solder stop layer has a metal oxide or a reduced form of the metal oxide. The metal oxide has at least one oxidation stage, which, assuming an activity coefficient of Rakt=1 at an inverse temperature of 8·10−4/K, has an oxygen coexistence decomposition pressure of not less than 1−23 MPa (10−23· bar) and not more than 1−12 MPa (10−12· bar) and which, assuming an activity coefficient of Rakt=1, at an inverse temperature of 9·10−4/K has an oxygen coexistence decomposition pressure of not less than 1−27 MPa (10−27 bar) and not more than 1−15 MPa (10−15 bar). Suitable metal oxides are, for example, oxides of chromium, tungsten or titanium.