372596186

RIKEN Accel. Próg. Rep. 24 (1990)

V-2-30. Manufacture of a Complicated Ceramic Chamber and Its Joining

Methods to an Aluminum-alloy Chamber

T. Nishidono, S. Yokouchi, H. Daibo, T. Toga,* and S.H. Be

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wiih hydrostaic prcss. at- ImO r

Ni clectroplaiing after Ho Hn letali/ing 10 im. ai 830 --8S0 X: in vacuui fumace. TIG welding

Fig. 2. Fabrication process of a ceramic chamber.

Mo-Mn ( 10 -20 pm ) j_ Metalliziog

Alumina ceramics \

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We are considering to use alumina ceramic chambers to prevent eddy current generating on the surface of the chamber used in fast bump magnets.⁰ Since the materiał of normal vacuum chambers in SPring-8 is aluminum-alloy, joining of ceramics to aluminum metals is required.

(a)

Fig. 1. Cross-sectional view of ceramic chambers. (a) for No. 1, No. 2, and No. 3 bump magnet. No. 2 and No. 3 are 200 mm in length; No. 1 is 300 mm in length. (b) for No. 4 bump magnet, 350 mm in length.

The cross-sectional views of two different ceramic chambers designed for SPring-8 are shown in Fig. 1. A ceramic chamber of a simple geometry as shown in Fig. 1 (a) can be manufactured easily, and direct joining of ceramics to aluminum (Al)-alloy is feasible by using an existing techniąue. However the manufacture of a complicated chamber of 35 cm in length and 26 cm in width as shown in Fig. 1 (b) is difficult, and the joining of this chamber to Al-alloy one is not easy either. Therefore its manufacture technique is reąuired to be estab-lished.

A manufacture process of the ceramic chamber is shown in Fig. 2. An important subject in the process is to improve a manufacture accu-racy. A particular attention is paid to the joining method because the joint must be stronger and leak-tight. For the complicated ceramic chamber, direct joining to stainless-steal (SUS) or

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4

6

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Al-alloy is impossible because of thermal stress caused by large thermal expansion mismatch between the two. A joining process of ceramics to Al-alloy is shown in Fig. 3. To minimize the stress in the seal or ceramics, SUS of a different expansion coefficient can be jointed with a grad-ed seal.

The seal consists of Fe-Ni-Co alloy (KOVAR) segment, which have a slightly different expan-sion and forms a zonę of gradual transition with

Ni ( 2 - 5 pm ) : Electroplating Ag ( - 100 pm ) : Brazing

Fe-Ni-Co Alloy ( KOVAR )

Fig. 3. (a) Geometry of a transition piece; (b) detail of the joining area of a KOYAR piece.

*

KYOCERA Corporation.