Patent ID: 7781071

Claim:
A brazed heat exchanger assembly comprising extruded heat exchanger tubes joined to heat exchanger fins; wherein said heat exchanger tubes are formed of a first aluminum alloy comprising 0.4 to 1.1% percent by weight manganese, up to 0.01% by weight copper, up to 0.05% by weight zinc, up to 0.2% by weight iron, up to 0.2% by weight silicon, up to 0.01% by weight nickel, up to 0.05% by weight titanium, and a balance of aluminum and incidental impurities; wherein said heat exchanger fins are formed of a second aluminum alloy comprising 0.9 to 1.5% by weight manganese and at least 0.5% by weight zinc; wherein the heat exchanger tubes exhibit good self corrosion protection and the heat exchanger fins are galvanically sacrificial relative to the heat exchanger tubes; and wherein the manganese weight percent of the first aluminum alloy is related to the manganese weight percent of the second aluminum alloy by the formula Mn tube (wt %)>Mn fin (wt %)−0.8 wt % where Mn tube is the manganese weight percent of the first aluminum alloy and Mn fin is the manganese weight percent of the second aluminum alloy.