| 摘要 |
PURPOSE:To enable to braze at minimum flux concentration sufficient for brazing a tube with corrugated fins in a furnace by a method wherein the electrode potentials of corrugated fins are set low so as to subject the corrugated fins to selective sacrificial corrosion. PURPOSE:Aluminum or aluminum alloy is used as the material for a tube, while an aluminum alloy coated on its surface with an in-furnace brazing material and made baser in electrode potential than the tube by addition of Zn, Sn, In or the like is used as the material for corrugated fins. For example, the core material for the corrugated fins 2 may be A3003 added with 2% of Zn and coated with BA4343 at a coverage of 10%. After immersing the core in a 10% aqueous solution of a flux, the core is passed through a brazing furnace. After brazing Zn in the core material of the fins 2 is allowed to diffuse so as to increase the Zn concentration at the surfaces of the fins. Provided with such distribution of Zn, the fins 2 serve as effective sacrificial corrosion fins to prevent Al from pitting when exposed to corrosive environments. |
