Preparation Of Fe₃Si Based IMC And Its Property Research In Different Kinds Of Corrosion Solution

With the rapid development of industry, the material conditions of use harshes, along with the continuous hard material use limit arrival, the existing material has been unable to meet some severe conditions requests, prompting scientists to constantly explore new materials. The insoluble intermetallic Fe₃Si has excellent resistance of corrosion, oxidation and friction, simple preparation, raw material is low become a potential structural materials. However, for a long time, the intrinsic brittleness of the Fe₃Si has been a stumbling block to its application, the introduction of plastic phase is essential.The experiment used mechanical alloying, through the method of hot-pressing sintering, preparated the Fe₃Si, Fe₃Si-5%Cu, Fe₃Si-10%Cu, and by XRD, SEM, EPMA etc to characterize the prepared samples. Comparing the three kinds of materials in hardness, microstructure, microarea composition, three point bending and compression test, the addition of Cu in Fe₃Si based IMC material has some improvement for its intrinsic brittleness, so for its corrosion resistance? Will Fe₃Si-Cu alloy developed into a corrosion resistant structure materials?The experimental compared the corrosion behavior of the three kinds of materials in different molarity acid, alkali, salt (NaCl, H₂SO₄, NaOH). Through the two methods of normal temperature static immersion corrosion and electrochemical corrosion discussed the corrosion behavior of Fe₃Si and Fe₃Si-Cu (5wt%, 10wt%) composite materials in different molarity of H₂SO₄, NaOH and NaCl solution. The results show that the addition of Cu in Fe₃Si based IMC materials has some rise for its free corrosion potential in different corrosion medium, improve the corrosion resistance of the material, and the Fe₃Si-5%Cu has a less free-corrosion current and corrosion rate. The corrosion process of the materials in H₂SO₄ solution are the most intense, In the process the air bubble from the surface of the materials emitting and its immersion corrosion rate is larger, after corrosion, the surface of the materials appeared different characteristics, in the Fe₃Si coated with a layer of compact white film, via testing it is SiO₂ to hindrance further corrodes. In the surface of Fe₃Si-5%Cu and Fe₃Si-10%Cu appeared different degree of reddish-brown and black, The PH value have no change through the reaction, From the polarization curve, the process of the three materials in the H₂SO₄ solution is a kind of passivation process, has an obvious passivation platform, and a broad passivation area, the polarization curve of Fe₃Si in different molarity of H₂SO₄ solution appeared a sharply current drop with the potential increase; The corrosion process of the three materials in NaOH solution are relatively gentle, after immersion corrosiaon, the surface of the materials appeared a degree of yellowish-brown corrosion products, The PH value of the corrosion solution changed in the 10th day in long-term immersion corrosion, The PH value began from 12 eventually become 9. From the polarization curve, the three kinds of materials in NaOH solution appeared obvious passivation; In the NaCl solution the three kinds of materials have a different process with the former two solution in the immersing corrosion, it is an activation process, the surface of the materials appeared many tan attachments at the earlier time, along with the lengthen of immersion corrosion, the corrosion products become more and more diffusion from the material surface gradually to the solution, evenly dispersed the internal solution, The PH value have no change, via testing the corrosion process produced Fe₂O₃, SiCl₄, FeCl₂, SiO₂, etc substance .