设计了不同成分的铜镍合金铸铁,并用静态失重法测定其在室温浓碱液中的腐蚀速率,借助光学显微镜和X射线衍射仪分析了显微组织和相组成.结果表明：随着铜含量的增加,铜镍合金铸铁初生石墨周围的小片状石墨细化显著,而初生石墨先是细化,后又粗化并且数量增多;当铜超过一定含量时,合金铸铁中析出铜化合物或游离铜,并且这些新相成为活性阴极相,降低合金铸铁的耐碱腐蚀性能.在室温浓碱液的静态腐蚀条件下,铜质量分数为4.5%的铜镍合金铸铁耐腐蚀性能相对较好.

The Cu-Ni alloy cast irons of different chemical constitution were designed,and the corrosion rate in room-temperature concentrated alkaline solution was measured by the static hydrometer method,the microscopics and phase composition of alloy cast iron were observed by optical microscope and XRD.The results show that with copper content increased,the small flake graphites’ refinement around Cu-Ni alloy cast iron become noteable,the primary graphite is refined firstly,and then is coased,meanwhile the quantity of it increased.When copper content exceeds the certain value,free copper element is precipitated in Cu-Ni alloy cast iron,and these new phase become active cathode phase,thus reduce the corrosion resistances of alloy cast irons.Under the room-temperature concentrated alkaline solution static condition,the corrosion resistance of alloy cast iron with 4.5wt% Cu is better.