Brazing composition, heat exchanger tube, and heat exchanger

A method of producing a coating, the method comprising applying a brazing composition to a coating and drying, the brazing composition comprising:

• 1 parts by mass or more and 10 parts by mass or less of Zn powder,
• 1 parts by mass or more and 5 parts by mass or less of Si powder,
• 3 parts by mass or more and 10 parts by mass or less of a K—Al—F flux, and
• 1 parts by mass or more and 3 parts by mass or less of methacrylate resin, and
• having a mass ratio (Zn/Si) of Zn powder relative to Si powder of 1 or more and 4 or less,
• such that the coating after the drying comprises
• 1 g/m2 or more and 10 g/m2 or less of Zn powder,
• 1 g/m2 or more and 5 g/m2 or less of Si powder,
• 3 g/m2 or more and 10 g/m2 or less of a K—Al—F flux, and
• 1 g/m2 or more and 3 g/m2 or less of methacrylate resin, and
• has a mass ratio (Zn/Si) of Zn powder relative to Si powder of 1 or more and 5 or less,
• wherein the total amount of Zn powder, Si powder, K—Al—F flux, and (meth)acrylic resin is 6 g/m2 or more and 20 g/m2 or less,
• the methacrylate resin is a (meth)acrylate polymer, and
• the (meth)acrylate polymer is a copolymer of (meth)acrylates and methacrylic acid.