Bronze alloy, process for producing the same, and sliding member comprising bronze alloy

摘要

A bronze alloy includes copper, tin, bismuth, nickel and sulfur and a metal structure of the bronze alloy has an eutectoid phase including α-copper having a lamellar structure including a flaky copper-tin intermetallic compound precipitated and metal particles including the bismuth dispersedly precipitated therein.

主权项

1. A bronze alloy, consisting of:
copper; tin; bismuth; nickel; and sulfur, wherein a content of the tin is 8- 15 mass % relative to a total mass of the bronze alloy, a content of the bismuth is 0.5- 7.0 mass % relative to the total mass of the bronze alloy, a content of the nickel is 0.5- 5.0 mass % relative to the total mass of the bronze alloy, a content of the sulfur is 0.1- 1.0 mass % relative to the total mass of the bronze alloy, the nickel and the bismuth inhibit a development of δ-copper and lower a eutectoid transformation temperature through compositional super cooling, the sulfur inhibits a diffusion of the tin in the copper and facilitates solidification segregation through lowering of a solubility limit of α-copper in order to cause a large quantity of γ-copper to be transformed from β-copper, and a metal structure of the bronze alloy comprises an eutectoid phase including the α-copper having a lamellar structure including a flaky copper-tin intermetallic compound precipitated and metal particles including the bismuth dispersedly precipitated therein, and the α-copper and copper-tin based intermetallic compound in a laminate in a form of pearlite.