Active brazing solder for brazing alumina-ceramic parts

• US 6,770,377 B2
• Filed: 06/12/2002
• Issued: 08/03/2004
• Est. Priority Date: 07/25/1996
• Status: Expired due to Fees

• Current Assignee: Endress+Hauser GmbH+Co (ENDRESS)
• Original Assignee: Endress+Hauser GmbH+Co (ENDRESS)
• Inventors: Müller, Heinz, Güther, Volker, Breme, Jürgen, Turnsek, Jürgen Peter, Schmidt, Elke Maria, Allo, Anobecs, Hegner, Frank
• Primary Examiner(s): Wyszomierski, George
• Assistant Examiner(s): MORILLO, JANELL COMBS
• Application Number:
  US10/170,852
• Publication Number:
  US 20020155020A1
• Time in Patent Office: 783 Days
• Field of Search: 737/00--56, 428/469, 420/422, 148/421, 228/121, 228/124.5
• US Class Current: 428/469
• CPC Class Codes: B22F 9/023 Hydrogen absorption
• CPC Class Codes: B23K 35/32 with the principal constituent melting at more than 1550 degrees C
• CPC Class Codes: C04B 2237/122 based on refractory metals
• CPC Class Codes: C04B 2237/127 The active component for bonding being a refractory metal
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 37/006 consisting of metals or metal salts

Abstract

The active brazing solder for brazing ceramic parts of alumina, particularly of high-purity alumina, contains a maximum of 12 wt. % Ti, a maximum of 8 wt. % Be, and less than 16.5 wt. % Fe, the remainder being Zr and any impurities that may be present. The active brazing solder has the following behaviour/features: Brazing temperature: lower than 1,000° C.; the brazed joint is high-vacuum-tight over a long period of time; the coefficient of thermal expansion of the active brazing alloy is substantially identical to that of the alumina ceramic in the entire temperature range covered during the brazing process; the strength of the brazed joint between the two ceramic parts is so high that under tensile loading, fracture will result not at the joint, but in the adjacent ceramic; the pressure resistance of the active brazing solder is greater than 2 GPa; the active brazing solder is very good processable into powders having particle sizes on the order of 10 μm.

Claims

1. A capacitive or resistive pressure sensor, comprising:

a first alumina-ceramic part;

a second alumina-ceramic part; and

a brazed joint that unites said first alumina-ceramic part to said second alumina-ceramic part, said brazed joint formed from a brazing solder consisting essentially of 8.6 wt. % to 12 wt. % titanium, 1 wt. % to 8 wt. % beryllium, 0 wt. % to 16.5 wt. % iron, 63.5 wt. % to 90.4 wt. % zirconium, and a remainder being any impurities.

2. The pressure sensor of claim 1, wherein

said active brazing solder has a melting point below 1000° C.

3. The pressure sensor of claim 1, wherein

said active brazing solder has a melting point between 700°

C. and 980°

C.

4. The pressure sensor of claim 1, wherein

said brazed joint was formed from an active brazing paste comprising said active brazing solder.

5. The pressure sensor of claim 1, wherein

said active brazing solder consists essentially of about 10 wt. % titanium, about 4 wt. % beryllium, and about 86 wt. % zirconium.

6. The pressure sensor of claim 1, wherein

said active brazing solder consists essentially of about 8.6 wt. % titanium, about 4 wt. % beryllium, about 15.8 wt. % iron, and about 71.6 wt. % zirconium.

7. The pressure sensor of claim 1, wherein

said active brazing solder consists essentially of about 8.8 wt. % titanium, about 2 wt. % beryllium, about 16.2 wt. % iron, and about 73 wt. % zirconium.

8. The pressure sensor of claim 1, wherein

said active brazing solder consists essentially of about 8.9 wt. % titanium, about 1 wt. % beryllium, about 16.3 wt. % iron, and about 73.8 wt. % zirconium.

9. The pressure sensor of claim 1, wherein

said brazed joint has a pressure resistance of at least 2 Gigapascals.

10. The pressure sensor of claim 1, wherein

said first ceramic part, said second ceramic part, and said brazed joint define a vacuum-tight chamber.