Brazing flux
AssigneesKabushiki Kaisha Toyota Chuo Kenkyusho, Nippondenso Co., Ltd.
InventorsFumio Shimizu, Fusayoshi Miura, Kenichi Suzuki, Yoshihiro Kinoshita
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Abstract
A brazing flux comprises cesium fluoride, aluminum fluoride, and crystalline aluminum hydroxide or aluminum oxide or both which form a crystalline compound having the following composition and containing cesium in the form of a complex salt: x.multidot.CsF-y.multidot.AlF.sub.3 -1/2.multidot.z.multidot.[Al.sub.2 O.sub.3 .multidot.nH.sub.2 O and/or Al.sub.2 O.sub.3 ] where x+y+z=100, x/y.ltoreq.3, 42.ltoreq.x.ltoreq.66, and z.gtoreq.2 in terms of mol %. The crystalline compound has a melting point of 440.degree. to 580.degree. C. The brazing flux is non-corrosive and safe to use, and well suited for a brazing aluminum materials with a high magnesium content and also for torch brazing.
Claims15
A brazing flux suitable for brazing aluminum materials with a high magnesium content, comprising cesium fluoride, aluminum fluoride, and at least one material selected from the group consisting of crystalline aluminum hydroxide and crystalline aluminum oxide, said brazing flux being a crystalline compound having the following composition and containing cesium in the form of a complex salt:
- x.multidot.CsF-y.multidot.AlF.sub.3 -1/2.multidot.z.multidot.[Al.sub.2 O.sub.3 .multidot.nH.sub.2 O and/or Al.sub.2 O.sub.3 ]
- where x+y+z=100, x/y.ltoreq.3, 42.ltoreq.x.ltoreq.66, and z.gtoreq.2 in terms of mol %.
A process for producing a brazing flux suitable for brazing aluminum materials with a high magnesium content, comprising
- preparing a mixture of hydrofluoric acid, cesium salt, and at least one selected from the group consisting of crystalline aluminum hydroxide and crystalline aluminum oxide, and
- causing reaction of said mixture to form a crystalline compound which has the following composition and contains cesium in the form of a complex salt:
- x.multidot.CsF-y.multidot.AlF.sub.3 -1/2.multidot.z.multidot.[Al.sub.2 O.sub.3 .multidot.nH.sub.2 O and/or Al.sub.2 O.sub.3 ]
- where x+y+z=100, x/y .ltoreq.3, 42 .ltoreq.x .ltoreq.66, and z .gtoreq.2 in terms of mol %.
A process for brazing aluminum materials with a high magnesium content, comprising
- preparing a flux comprising a crystalline compound which has the following composition and contains cesium in the form of a complex salt:
- x.multidot.CsF -y.multidot.AlF.sub.3 -1/2.multidot.z.multidot.[Al.sub.2 O.sub.3 .multidot.nH.sub.2 O and/or Al.sub.2 O.sub.3 ]
- where x+y+z=100, x/y .ltoreq.3, 42 .ltoreq.x .ltoreq.66, and z .gtoreq.2 in terms of mol %,
- preparing brazing material comprising at least one member selected from the group consisting of Al-Si alloy, Al-Si-Cu alloy, Al-Si-Cu-Zn alloy, Al-Zn-Si alloy, and Al-Zn alloy, and
- applying said flux and said brazing material to a joint of aluminum materials, and heating the joint at a temperature higher than the melting point of said brazing material,
- thereby joining said aluminum materials.
Dependencies are inferred from the claim text.