Insights on the Influence of Surface Chemistry and Rim Zone Microstructure of 42CrMo4 on the Efficiency of ECM.

摘要: The electrochemical machining (ECM) of 42CrMo4 steel in sodium nitrate solution is mechanistically characterized by transpassive material dissolution and the formation a Fe3−xO4 mixed oxide at surface. It assumed that efficiency removal during ECM depends on structure composition this layer as well microstructure material. Therefore, different microstructures (ferritic–pearlitic martensitic) was subjected to two processes with current densities about 20 A/cm2 34 A/cm2, respectively. process electrolyte analyzed via mass spectrometry inductively coupled plasma order obtain information reaction mechanisms. This followed an X-ray photoelectron spectroscopy analysis detect chemical binding states elements formed ECM. In summary, it has been demonstrated both 5–10% higher for martensitic than ferritic–pearlitic 42CrMo4. one hand attributed presence cementite phase 42CrMo4, which promotes oxygen evolution therefore negative effect efficiency. On other hand, increasing proportion Fe2O3 leads increase