PRESSURE SENSOR AND METHOD FOR MANUFACTURING A PRESSURE SENSOR

Abstract

The present disclosure relates to a method for manufacturing a pressure sensor having a main body and a pressure-sensitive ceramic measurement membrane, wherein an outer edge of the measurement membrane is connected in a pressure-tight manner by an encircling joint to a surface of the main body facing the outer edge of the measurement membrane, wherein the joint includes a ternary active hard solder in eutectic composition: providing the main body, the measurement membrane and the active hard solder; positioning the active hard solder between the outer edge of the measurement membrane and the surface of the main body; heating the main body, the measurement membrane and the active hard solder to a joining temperature which essentially corresponds to a temperature of the eutectic point of the active hard solder.

Claims

1-10. (canceled)

11. A pressure sensor comprising a main body and a pressure-sensitive ceramic measurement membrane, wherein an outer edge of the measurement membrane is connected in a pressure-tight manner by an encircling joint to a surface of the main body facing the outer edge of the measurement membrane so as to enclose a pressure chamber, wherein the joint includes a ternary active hard solder in eutectic composition, the pressure sensor fabricated by a method comprising: providing the main body, the measurement membrane and the active hard solder; positioning the active hard solder between the outer edge of the measurement membrane and the surface of the main body facing the outer edge of the measurement membrane; heating the main body, the measurement membrane and the active hard solder to a joining temperature, which essentially corresponds to a temperature of the eutectic point of the active hard solder; and cooling the pressure sensor below the joining temperature.

12. The pressure sensor of claim 11, wherein the active hard solder consists essentially of zirconium, nickel, and titanium in an atomic ratio of Zr:Ni:Ti=47:26:27 atomic percentage (at %) within an error of ±5 at %.

13. The pressure sensor of claim 11, wherein the joining temperature is approximately 770° C.

14. The pressure sensor of claim 11, wherein the joining temperature is within a temperature range that is 2-10% above a melting point of the active hard solder.

15. The pressure sensor of claim 11, wherein the joining temperature is within a temperature range that is 2-5% above a melting point of the active hard solder.

16. The pressure sensor of claim 11, wherein the joining temperature is within a temperature range of 770° C. to 860° C.

17. The pressure sensor of claim 11, wherein the joining temperature is within a temperature range of 790° C. to 820° C.

18. The pressure sensor of claim 11, wherein the main body is ceramic.

19. The pressure sensor of claim 11, wherein the measurement membrane and/or the main body are made of corundum.

20. A method for fabricating a pressure sensor that comprises a main body and a pressure-sensitive ceramic measurement membrane, wherein an outer edge of the measurement membrane is connected in a pressure-tight manner by an encircling joint to a surface of the main body facing the outer edge of the measurement membrane so as to enclose a pressure chamber, wherein the joint includes a ternary and eutectic active hard solder, the method comprising: providing the main body, the measurement membrane and the active hard solder; positioning the active hard solder between the outer edge of the measurement membrane and the surface of the main body facing the outer edge of the measurement membrane; heating the main body, the measurement membrane and the active hard solder to a joining temperature which essentially corresponds to a temperature of the eutectic point of the active hard solder; and cooling the pressure sensor below the joining temperature.

21. The method of claim 20, wherein the active hard solder consists essentially of zirconium, nickel, and titanium in an atomic ratio of Zr:Ni:Ti=47:26:27 atomic percentage (at %) within an error of ±5 at %.

22. The method of claim 20, wherein the joining temperature is approximately 770° C.

23. The method of claim 20, wherein the joining temperature is within a temperature range that is 2-10% above a melting point of the active hard solder.

24. The method of claim 20, wherein the joining temperature is within a temperature range that is 2-5% above a melting point of the active hard solder.

25. The method of claim 20, wherein the joining temperature is within a temperature range of 770° C. to 860° C.

26. The method of claim 20, wherein the joining temperature is within a temperature range of 790° C. to 820° C.

27. The method of claim 20, wherein the main body is ceramic.

28. The method of claim 20, wherein the measurement membrane and/or the main body are made of corundum.

Description

[0040] FIG. 1: shows a schematic representation of a pressure sensor according to the invention.

[0041] FIG. 2: shows an exemplary embodiment of the method according to the invention.

[0042] The pressure sensor 1 according to the invention, as shown schematically in FIG. 1 in a sectional drawing, comprises a, for example ceramic, main body 2 and a ceramic measurement membrane 3. In the present example, both the main body 2 and the measurement membrane 3 are made of corundum. While enclosing a pressure chamber 4, an outer edge of the measurement membrane 3 is connected in a pressure-tight manner, by means of an encircling joint 5, to a surface of the main body 2 facing the outer edge of the measurement membrane 3. In order to apply a first pressure to the measurement membrane 3, a pressure supply line 10 optionally leads through the main body 2 into the pressure chamber 4. The second pressure is provided to the measurement membrane 3 at its surface facing away from the pressure chamber 4.

[0043] Pressure sensors of this type are manufactured and marketed by the applicant under the names Cerabar and Ceraphant.

[0044] The pressure sensor 1 further has, for example, a capacitive transducer which comprises a measuring electrode 7 on the surface of the measurement membrane 3 facing the pressure chamber 4 and a counter-electrode 8 on a surface of the main body 2 facing the pressure chamber 4. The counter-electrode 8 is contacted via an electrical conductor, which is designed as a contact pin 9, for example.

[0045] The joint 5 has a ternary active hard solder in eutectic composition, wherein a joining temperature of the joint 5 essentially corresponds to a temperature of a melting point of the active hard solder 6. The active hard solder 6 can consist, for example, of zirconium, nickel and titanium in an atomic ratio of Zr:Ni:Ti=47:26:27 at % with an error of ±5 at %; in particular the ratio of Zr:Ni:Ti=47:26:27 at % can have an error of up to ±3 at %, up to ±2 at %, or up to ±1 at %.

[0046] For example, the joining temperature of the pressure sensor is approximately 770° C. The joining temperature can optionally lie within a temperature range which is 2-10% or in particular 2-5% above the melting point of the active hard solder 6. Alternatively, the joining temperature can lie within a temperature range of 770° C. to 860° C. or in particular within a range of 790° C. to 820° C.

[0047] FIG. 2 shows an exemplary embodiment of the method according to the invention for manufacturing a pressure sensor 1 having a main body 2 and a pressure-sensitive ceramic measurement membrane 3. The pressure sensor according to the invention from FIG. 1 is obtainable by a method shown in FIG. 2. While enclosing a pressure chamber 4, an outer edge of the measurement membrane 3 is connected in a pressure-tight manner, by means of an encircling joint 5, to a surface of the main body 2 facing the outer edge of the measurement membrane 3, wherein the joint 5 has a ternary and eutectic active hard solder 6. In a first step 10 of the method according to the invention, the main body 2, the measurement membrane 3 and the active hard solder 6 are first provided and in a second step 20 positioned such that the active hard solder 6 is arranged between the outer edge of the measurement membrane 3 and a surface of the main body 2 facing the outer edge of the measurement membrane 3. In a third step 30, the main body 2, the measurement membrane 3 and the active hard solder 6 are heated up to a joining temperature which essentially corresponds to a temperature of the eutectic point of the active hard solder 6. The joining temperature is maintained for a defined period of time before the arrangement of measurement membrane 3 and main body 2 is cooled in a fourth step 40. In this way, a pressure sensor with a homogeneous joint between the measurement membrane 3 and the main body 2 is obtained.

LIST OF REFERENCE SIGNS

[0048] 1 Pressure sensor [0049] 2 Main body [0050] 3 Measurement membrane [0051] 4 Pressure chamber [0052] 5 Joint [0053] 6 Active hard solder [0054] 7 Measuring electrode [0055] 8 Counter-electrode [0056] 9 Contact pin [0057] 10 Pressure supply line