The Effect Of Rare Earth Element Ce On The Structure And Properties Of CuNi10Fe1.5Mn Alloy

Corrosion-resistant iron-white copper,represented by CuNi10Fe1.5Mn(CNS C70600)alloy,is mainly used in corrosion-sensitive parts with high corrosion resistance requirements such as seawater pipelines,condensers and heat exchangers.Although the CuNi10Fe1.5Mn alloy is excellent in corrosion resistance,corrosion failure occurs during use.Various measures(such as surface passivation treatment,corrosion inhibitor,etc.)have been adopted for corrosion failure of corrosion-resistant iron-white copper.However,due to working conditions,some key parts cannot be used.At present,improving the corrosion resistance of the alloy by alloying is still the most direct and effective method.In this paper,salt spray corrosion test,electrochemical test,combined mechanical property test and metallographic observation were used to analyze the microstructure and mechanical properties of CuNi10Fe1.5Mn-xCe alloy in cold deformation state and annealing state.The corrosion behavior of CuNi10Fe1.5Mn-xCe alloy in cold deformed state and annealed state in 3.5 wt.% NaCl neutral solution was studied,The main conclusions are as follows:(1)Under the annealing condition of 750 °C × 25 min,the degree of recrystallization of CuNi10Fe1.5Mn alloy decreases with the increase of Ce content(within the experimental range);(2)The addition of Ce reduces the plasticity of CuNi10Fe1.5Mn alloy,and the plasticity of cold-deformed alloy is more affected by Ce content than that of annealed alloy.(3)The addition of rare earth Ce reduces the open circuit potential of CuNi10Fe1.5Mn alloy,and the open circuit potential of the alloy in the annealed state is more affected by the content of rare earth Ce;(3)The addition of rare earth Ce reduces the open circuit potential of the CuNi10Fe1.5Mn alloy,and the alloy open circuit potential in the annealed state is more pronounced;(4)In the initial stage of immersion,the corrosion resistance of CuNi10Fe1.5Mn alloy with cold-deformed state of added rare earth Ce is improved,but if long-term corrosion is carried out,the effect of Ce improving the corrosion resistance of the alloy will be weakened;(5)CuNi10Fe1.5Mn-xCe,whether it is cold-deformed or annealed,its corrosion products are similarly found by EDS analysis,mainly composed of a relatively bulky outer membrane and a dense inner membrane.The outer membrane mainly contains There are three elements of O,Cl and Cu,and the inner layer contains Ni,Fe and Mn elements in addition to the above three elements,but no Ce element is detected;(6)After immersion for 25 days,when the Ce content is 0,the corrosion degree of the alloy is more serious than that of the rare earth-added alloy,whether it is cold-formed or annealed.In addition,the corrosion degree of the alloy is reduced after annealing.