Ceramic pressure sensor and method for its production

Patent metadata

Field	Value
Publication number	US-9835510-B2
Application number	US-201514876221-A
Country	US
Kind code	B2
Filing date	Oct 6, 2015
Priority date	Oct 13, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A ceramic pressure sensor is described which is produced using an alternative production method and has a ceramic base body, a ceramic measuring membrane which is disposed on the base body and is to be charged with a pressure to be measured, and a pressure measuring chamber enclosed in the base body below the measuring membrane. A method to produce the pressure sensor by means of which, in particular, more complex shapes of the measuring membrane and/or the base body are producible with minimal pores wherein the base body and/or the measuring membrane have layers applied on each other in a 3-D printing method and produced by the selective laser melting of nanopowder layers.

First claim

The invention claimed is:

1. A pressure sensor, comprising:
a ceramic base body;
a ceramic measuring membrane that is disposed on said base body and that is exposed to a pressure to be measured; and
a pressure measuring chamber enclosed in said base body under said measuring membrane, wherein:
said base body and/or said measuring membrane comprises layers which are applied on each other in a 3-D printing method and produced by the selective laser melting of nanopowder layers.

2. The pressure sensor according to claim 1 , wherein:
said layers have a layer thickness within the micrometer range.

3. The pressure sensor according to claim 1 , wherein:
said base body and/or said measuring membrane comprise at least one structure consisting of stacked layers of corresponding footprint.

4. The pressure sensor according to claim 3 , wherein:
said base body has an elevation on its end face facing measuring said membrane; and
said elevation is a structure consisting of stacked layers.

5. The pressure sensor according to claim 3 , wherein:
said measuring membrane has a reinforcement in a central region; and
said reinforcement is a structure consisting of stacked layers.

6. The pressure sensor according to claim 3 , wherein:
an outer edge of said measuring membrane is connected by a joint to an outer edge of an end face of said base body facing said measuring membrane;
in a region of said end face of the base body facing said measuring membrane directly adjacent to an inner side of said joint, said base body has a groove which is closed to form a ring; and
said groove is a structure consisting of stacked openings, which are closed to form a ring, in the layers of said base body facing said measuring membrane.

7. The pressure sensor according to claim 1 , wherein:
the pressure sensor has a capacitive electromechanical converter for measuring a deflection of said measuring membrane depending on the pressure acting on said measuring membrane;
said converter has an electrode disposed on a side of said measuring membrane facing said base body and a counter electrode disposed on the side of said base body facing said measuring membrane; and
said electrode and/or said counter electrode have at least one layer printed in a 3-D printing method, in particular a layer generated by applying a metallic nanopowder layer, in particular a nanopowder layer consisting of titanium or tantalum metal powder, selective laser melting and subsequent hardening.

8. The pressure sensor according to claim 1 , wherein:
the pressure sensor has a capacitive electromechanical converter for measuring a deflection of said measuring membrane depending on the pressure acting on said measuring membrane;
said converter has a counter electrode disposed on a side of said base body facing said measuring membrane, in particular said counter electrode having at least one layer generated by applying a metallic nanopowder layer, in particular a nanopowder layer consisting of titanium or tantalum metal powder, selective laser melting and subsequent hardening;
said base body comprises a connecting line which runs from said counter electrode to a connecting point disposed on an outer lateral surface of said base body, in particular to a connecting point disposed on an outside lateral surface of said base body;
said base body has stacked layers which are produced by the selective laser melting of nanopowder layers and through which said connecting line runs;
these layers each have one ceramic and one metallic region;
the metallic regions of the adjoining layers are adjacent to each other; and
the adjoining metal regions form said connecting line.

9. The pressure sensor according to claim 1 , wherein:
the pressure sensor has a membrane bed that is constructed from stacked layers produced by the selective laser melting of nanopowder layers.

10. The pressure sensor according to claim 1 , wherein:
in said base body, a bore is provided that ends in a pressure measuring chamber running through said base body;
said base body has stacked layers which are produced by the selective laser melting of nanopowder layers and through which said bore runs; and
said bore consists of adjoining openings provided in these layers.

11. The pressure sensor according to claim 1 , wherein:
said base body and/or said measuring membrane consists of ultrapure ceramic, in particular ultrapure aluminum oxide (Al 2 O 3 ), in particular aluminum oxide (Al 2 O 3 ) with a degree of purity greater than or equal to 95%, in particular greater than or equal to 99%, or ultrapure zirconium oxide (ZrO 2 ), in particular zirconium oxide (ZrO 2 ) with a degree of purity greater than or equal to 95%, in particular greater than or equal to 99%.

12. A method for the production of a pressure sensor, comprising:
a ceramic base body; a ceramic measuring membrane that is disposed on said base body and that can be charged with a pressure to be measured; and a pressure measuring chamber enclosed in said base body under said measuring membrane, wherein: said base body and/or said measuring membrane comprises layers which are applied on each other in a 3-D printing method and produced by the selective laser melting of nanopowder layers; wherein
the ceramic layers of the pressure sensor are generated in a 3-D printing method in which each ceramic layer is generated as follows:
a nanopowder of the ceramic is applied in a nanopowder layer, in particular with a squeegee; and
the regions of the nanopowder layer forming the layer are fully melted by selective laser melting, in particular selective laser melting performed with a pulse laser generating laser pulses of short duration, in particular a picosecond laser or a femtosecond laser, and subsequently reharden.

13. A method for the production of a pressure sensor, which comprises:
a ceramic base body; a ceramic measuring membrane that is disposed on said base body and that is exposed to a pressure to be measured; and a pressure measuring chamber enclosed in said base body under said measuring membrane, wherein: said base body and/or said measuring membrane comprises layers which are applied on each other in a 3-D printing method in a melting of nanopowder layers; the pressure sensor has a capacitive electromechanical converter for measuring a deflection of said measuring membrane depending on the pressure acting on said measuring membrane; said converter has an electrode disposed on a side of said measuring membrane facing said base body and a counter electrode disposed on the side of said base body facing said measuring membrane; and said electrode and/or said counter electrode have at least one layer printed in a 3-D printing method, in particular a layer generated by applying a metallic nanopowder layer, in particular a nanopowder layer consisting of titanium or tantalum metal powder, selective laser melting and subsequent hardening; and
the metallic layers of the pressure sensor are generated in a 3-D printing method in which each metallic layer is generated as follows:
a nanopowder of the metal is applied in a nanopowder layer, in particular with a squeegee; and
the regions of the nanopowder layer forming the metallic layer are fully melted by selective laser melting, in particular selective laser melting performed with a pulse laser generating laser pulses of short duration, in particular a picosecond laser or a femtosecond laser, and subsequently reharden.

14. A method for the production of a pressure sensor, comprising:
a ceramic base body; a ceramic measuring membrane that is disposed on said base body and that is exposed to a pressure to be me

Assignees

• Endress Hauser Gmbh Co Kg

Inventors

• Tham Anh Tuan

Classifications

• B22F12/90

  Means for process control, e.g. cameras or sensors · CPC title

• B22F12/43

  pulsed; frequency modulated · CPC title

• B22F10/25

  Direct deposition of metal particles, e.g. direct metal deposition [DMD] or laser engineered net shaping [LENS] · CPC title

• B22F10/28

  Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] · CPC title

• B33Y70/00

  Materials specially adapted for additive manufacturing · CPC title