Aluminum alloy brazing sheet, method for manufacturing the same, aluminum alloy sheet, and heat exchanger
An aluminum alloy brazing sheet used for brazing in an inert gas atmosphere without using flux includes a core material of aluminum or aluminum alloy, and a brazing material of aluminum alloy including Si of 4.0 mass % to 13.0 mass % and cladding one side surface or both side surfaces of the core material. One or both of the core material and the brazing material includes any one or two or more types of X atoms (X is Mg, Li, Be, Ca, Ce, La, Y, and Zr). The aluminum alloy brazing sheet is a brazing sheet in which oxide particles including the X atoms and having a volume change ratio of 0.99 or lower with respect to an oxide film before brazing heating are formed on a surface thereof, by brazing heating.
1. An aluminum alloy brazing sheet used for brazing in an inert gas atmosphere without using flux, the aluminum alloy brazing sheet comprising:
a core material of aluminum or aluminum alloy; and
a brazing material of aluminum alloy including Si of 4.0 mass % to 13.0 mass % and cladding one side surface or both side surfaces of the core material, wherein
one or both of the core material and the brazing material includes any one or two or more types of X atoms, X being selected from the group consisting of Li, Be, Ca, Ce, La, Y, and Zr,
when only the core material includes the X atoms, a content of each of the X atoms in the core material is 0.01 mass % to 2.0 mass %,
when only the brazing material includes the X atoms, a content of each of the X atoms in the brazing material is 0.001 mass % to 0.03 mass %,
when both the core material and the brazing material include the X atoms, a content of each of the X atoms in the core material is 0.01 mass % to 2.0 mass %, and a content of each of the X atoms in the brazing material is 0.001 mass % to 0.03 mass %,
an oxide film formed on a surface of the brazing material by brazing such that each of the X atoms in the oxide film has a molar ratio of 0.2 or lower with respect to Al in the oxide film, thereby leading to a volume change ratio of 0.99 or lower, wherein the volume change ratio is a volume per oxygen atom of oxide particles after brazing over volume per oxygen atom of the oxide particles before brazing.
2. The aluminum alloy brazing sheet according to claim 1 , wherein the oxide film formed on the surface of the aluminum alloy brazing sheet has a thickness of 30 nm or less.
3. The aluminum alloy brazing sheet according to claim 1 , wherein the core material is aluminum alloy including:
the X atoms in which a content of each type of the X atoms is 2.0 mass % or lower; and
any one or two or more types of Mn of 1.8 mass % or lower, Si of 1.2 mass % or lower, Fe of 1.0 mass % or lower, Cu of 1.5 mass % or lower, Zn of 3.0 mass % or lower, and Ti of 0.2 mass % or lower, with the balance being Al and inevitable impurities.
4. The aluminum alloy brazing sheet according to claim 1 , wherein the brazing material is aluminum alloy including:
Si of 4.0 mass % to 13.0 mass %; and
the X atoms in which a content of each type of the X atoms is 0.03 mass % or lower, with the balance being Al and inevitable impurities.
5. The aluminum alloy brazing sheet according to claim 1 , wherein the brazing material is aluminum alloy further including Bi of 0.004 mass % to 0.2 mass %.
6. The aluminum alloy brazing sheet according to claim 1 , wherein the brazing material dads one side surface, a sacrificial anode material dads the other side surface, and the sacrificial anode material is formed of aluminum alloy including Zn of 0.9 mass % to 6.0 mass % with the balance being Al and inevitable impurities.