The invention relates to a brazing sheet product comprising a core sheet, a clad layer on said core sheet made of an aluminum alloy containing silicon in an amount in the range of 4 to 14% by weight, an optional layer comprising nickel on the outersurface of said clad layer, and a diffusion layer comprising nickel-tin alloy on the outer surface of said nickel layer. The invention further relates to a method of manufacturing such a brazing product comprising the process step of plating different metal layers and subjecting the plated brazing product to an annealing treatment by holding the plated brazing product at a temperature in the range of 100 to 500.degree. C. for a period of 1 sec. to 300 minutes to form a diffusion layer comprising nickel-tin alloy on the outer surface of said layer comprising nickel.