MANUFACTURING METHOD OF COMPOSITE METAL MATERIAL

To provide a manufacturing method of a composite metal material which is provided with alloy containing a noble metal component on a discharge part, maintains durability, has a non-discharge part made of inexpensive alloy and achieves both high durability and low cost.SOLUTION: A composite metal material includes a columnar member and a cover-shaped member which covers a predetermined width of lateral surface continuous with an end surface and the surface of the columnar member. A manufacturing method of the composite metal material includes steps of: cutting a first metal raw wire and making the columnar member, making the cover-shaped member provided with a recessed part for covering a predetermined width portion of the lateral surface continuous with an end surface and the surface of the columnar member and combining the cover-shaped member and the columnar member. The columnar member is made from a Ni-based alloy, Fe-based alloy or first Pt-based alloy and the cover-shaped member is made from an Ir-based alloy or second Pt-based alloy. When the columnar member is made from the first Pt-based alloy and the cover-shaped member is made from the second Pt-based alloy, a ratio of noble metal component in the first Pt-based alloy in the columnar member is smaller than that of the noble metal component in the second Pt-based alloy in the cover-shaped member.SELECTED DRAWING: Figure 1 【課題】貴金属成分を含む合金を放電部に備えて耐久性を維持し、非放電部は安価な合金とし、高い耐久性と低コストとを両立する複合金属材の製造方法を提供する。【解決手段】複合金属材は、柱状部材と、その端面および該面に連なる側面の所定幅を被覆する蓋状部材よりなる。複合金属材の製造方法は、第１の金属素線を切断して柱状部材を作製する工程と、柱状部材の端面および該面に連なる側面の所定幅部分を被覆する凹部を備える蓋状部材を作製する工程と、蓋状部材と柱状部材を組み合わせる工程を含む。柱状部材はＮｉ基合金又はＦｅ基合金又は第１のＰｔ基合金からなり、蓋状部材はＩｒ基合金又は第２のＰｔ基合金からなる。柱状部材が第１のＰｔ基合金からなり且つ蓋状部材が第２のＰｔ基合金からなる場合には、柱状部材における第１のＰｔ基合金中の貴金属成分の比率は、蓋状部材における第２のＰｔ基合金中の貴金属成分の比率よりも小さい。【選択図】図１