Copper-nickel-tin alloy, method for the production thereof and use thereof

A copper-nickel-tin alloy consisting of (in % by weight):

• 2.0% to 10.0% Ni,
• 2.0% to 10.0% Sn,
• 0.01% to 1.5% Si,
• 0.002% to 0.45% B,
• 0.001% to 0.09% P,
• optionally up to a maximum of 2.0% Co,
• optionally up to a maximum of 2.0% Zn,
• optionally up to a maximum of 0.25% Pb,
• the balance being copper and unavoidable impurities,
• wherein
• the Si/B ratio of the element contents in % by weight of the elements silicon and boron is a minimum of 0.4 and a maximum of 8;
• after further processing of the alloy by at least one annealing operation or by at least one hot forming operation and/or cold forming operation, as well as at least one annealing operation, the following microstructure constituents are present:
• A) a metallic base composition having, based on the overall microstructure,
• A1) up to 15% by volume of first phase constituents that can be reported by the empirical formula CunNikSnm and have an (h+k)/m ratio of the element contents in atomic % of 2 to 6,
• A2) up to 5% by volume of second phase constituents that can be reported by the empirical formula CupNirSns and have a (p+r)/s ratio of the element contents in atomic % of 10 to 15, and
• A3) a balance of a solid copper solution;
• B) phases which, based on the overall microstructure, are present,
• B1) at 2% to 30% by volume as Si-containing and B-containing phases, Ni—Si borides having the empirical formula NixSi2B with x=4 to 6, as Ni borides, Ni phosphides and as Ni silicides in the microstructure, which are present individually and/or as addition compounds and/or mixed compounds and are ensheathed by precipitates of the (Cu, Ni)—Sn system,
• B2) at up to 80% by volume as continuous precipitates of the (Cu, Ni)—Sn system in the microstructure, and
• B3) at 2% to 30% by volume as Ni phosphides and Ni silicides in the microstructure that are present individually and/or as addition compounds and/or mixed compounds, are ensheathed by precipitates of the (Cu, Ni)—Sn system and have a size of less than 3 μm;
• the Si-containing and B-containing phases that are in the form of silicon borides, the Ni—Si borides and the Ni borides, Ni phosphides and Ni silicides that are present individually and/or as addition compounds and/or mixed compounds constitute seeds for static and dynamic recrystallization of the microstructure during the further processing of the alloy, which enables the establishment of a uniform and fine-grain microstructure;
• the Si-containing and B-containing phases that are in the form of boron silicates and/or boron phosphorus silicates, together with phosphorus silicates, assume the role of a wear-protecting and corrosion-protecting coating on semifinished materials and components of the alloy.