渗碳体石墨化制备无铅石墨黄铜的腐蚀性能

Corrosion properties of lead-free graphite brass prepared by graphitization of cementite

以共晶铸铁作为碳源,通过熔铸及渗碳体石墨化工艺制备不同石墨含量的石墨黄铜。对石墨黄铜进行脱锌腐蚀试验,通过SEM和EDS分析了石墨黄铜的腐蚀组织、腐蚀性能和石墨含量的关系,并探讨了石墨黄铜的腐蚀机理。结果表明:随着铸铁添加量的增加,石墨黄铜的耐腐蚀性先提高后降低,铸铁添加量为5%时,石墨黄铜的腐蚀产物会在合金表面形成一层完整氧化膜,腐蚀面基本没有裂纹和孔洞,脱锌层厚度最小,平均为144μm,其耐腐蚀性最好。石墨黄铜的耐腐蚀性能由其组织、成分及石墨颗粒的分布状态共同作用而成。

Eutectic cast iron(ECI)as carbon source was added into brass,graphite brass with different graphite content was prepared by the processes of fusion casting and cementite graphitization.The dezincification experiment of graphite brass was conducted.The relationship between corrosion structure,corrosion properties and graphite content of graphite brass was studied by SEM and EDS,and the corrosion mechanism of graphite brass was discussed.The resultsshowedthat the corrosion resistance of graphite brass increased first and then decreasedwith the increase of ECI content.When the addition of ECI was 5%,the corrosion resistance was the best.The corrosion products of graphite brassformed a complete oxidation film on the brass alloy surface,and there were no cracks and holes on the corroded surface.The thickness of the deszincized layer was the smallest with an average thickness of 144μm.The corrosion resistance of graphitic brass was synergistically determined by its structure,composition and the distribution of graphite particles.