| 摘要 |
PURPOSE:To obtain a heat exchanger which is superior in its durability by preventing pitting corrosion from generating, by making electric potential of a solder material layer forming an external layer of a liquid duct formed in three layers and an inside layer are made base as compared with that of an intermediate core material layer. CONSTITUTION:An aluminum material constituting a liquid duct 1 is made into layer structure consisting of a 5'15% clad ratio solder layer 9 constituting the outside, an intermediate core material layer 10 and a 5-15% clad ratio inside layer 11 constituting the inside. Electric potential of the solder material layer 9 obtained by adding 3-13% silicon and 0.2-3% zinc to aluminum and an inside layer 11 obtained by mixing a small amount of the other kind metal to aluminum are made base as compared with that of the core material layer 10 obtained by adding 0.2-0.5% copper and 0.3-0.6% manganese to aluminum, and when pitting corrosion is apt to make progess from either the outside or the inside of the liquid duct 1, the corrosion is prevented from reaching the core material layer 10 because of the sacrificial corrosion of the solder layer 10 or the core material layer 11. |
