| 摘要 |
PURPOSE:To form the base potential layer contg. Sn on the surface and to improve the corrosion resistance of the title heat exchanger with simple process by coating the Sn liquid or slurry in the specified amt. on the tube surface brazing a fin and executing a heated brazing. CONSTITUTION:A heated brazing is executed by coating the Sn liq. or slurry in the amt. about >=0.05mg/cm<2> consisting of at least one of SnF2 and Sncl2 on the tube surface brazing an A alloy made fin and the tube. The Sn contg. layer of more base potential than Al alloy base metal is formed on the surface to prevent the tube pitting corrosion generation of an Al alloy made heat exchanger. The corrosion resistance may be reinforced by contg. the Zn consisting of ZnF2 and ZnCl2 or the LiF for controlling m.p. may be added. Also the K compound for constraining corrosion at room, temp. may be added and the flux for brazing may be contd. The fin may be brazed in the state of plating Sn on the tube surface.
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