| Refractory metal silicide Fe3Si had excellent corrosion resistance, anti-oxidation, abrasion resistance and the preparation was simple, raw material was cheap, etc, therefore it became a potential structural material. But, has concentrated since long to the Fe3Si research in its magnetism and performance, are really few to its achievement structural material's research.this paper was studied on Fe3Si and Alloys prepared, anti-oxidation and corrosion resistance.Adopting mechanical ball-milling combined with hot-pressing and sintering method prepared Fe3-xCrxSi (x=0,0.2,0.4,0.6) alloys, and by XRD, SEM, EPMA and so on to characterize the prepared samples. Meanwhile,304 stainless steel was chosen as the reference,at 800℃and 900℃,high temperature anti-oxidation of the Fe3-xCrxSi alloys,and in 0.5mol/L,5mol/L and 10mol/L H2SO4 solution of corrosion resistance of the Fe3-xCrxSi alloys were studied.Different sintering temperature and holding time of the alloy samples were compared to determine the optimal sintering parameters:At sintering temperature 1100℃, holding time 60min, the main phases of alloys were Fe3Si and Fe3-xCrxSi solid solution phase. With the increase of Cr content, hardness and sintered density of samples increased, the compression strength was firstly increased and then decreased, and when x is 0.2, the compression strength of alloy had maximum and reached to 1860Mpa. The alloy cuts off degree of lip-rounding appearance gave first place to brittleness cleavage fracture, with Cr alloying elements, to some extent improved the brittleness of Fe3Si.It had studied on high temperature oxidation resistance of the alloy samples and reference samples at 800℃and 900℃. The results showed that the alloy samples had better oxidation resistance than the 304 stainless steel. The oxide film was composite and contained the main phases of SiO2,Cr2O3,FeCr2O4. With the addition of alloying elements Cr, the weight gain of oxidation decreased. It also well improved high temperature oxidation resistance of Fe3Si. When Cr was lower in alloys, the oxide film of Cr2O3 was too thin and easy to fall off, which could not paly a protective effect. At high oxygen partial pressure conditions, it was easy to generate the protective oxide film of FeCr2O4,Fe2.95Si0.05O4 spinels.It had further studied on corrosion resistance of the alloy samples(Fe3-xCrxSi) and reference samples (304 stainless steel) in H2SO4 solution of 0.5mol/L,5mol/L and 10mol/L. As can be seen from the polarization curves, all the alloy samples had obvious passivation region in H2SO4 solution of various concentrations. In H2SO4 solution of 0.5mol/L, the alloy samples which had lower corrosion potential and higher corrosion current were worse than the 304 stainless steel at corrosion resisitance. At the same time, the alloy samples had a wide passivated range. In H2SO4 solution of 10mol/L, the corrosion potential and corrosion current of all alloy samples were lower than the 304 stainless steel. The corrosion of alloys tended to be larger, but still better than that of the 304 stainless steel. With the increase of Cr, the blunt potential of Fe3-xCrxSi shift to negative and the range of passivation potential became wide. Meanwhile, the blunt current and passive current reduced, corrosion resistance increased. It showed that Fe3-xCrxSi was more likely to blunt in concentrated H2SO4 solution and generate passive film of SiO2 and Cr2O3. Immersion also showed similar characteristics. With the increase of Cr and concentration of H2SO4 solution, the weight loss of corrosion decreased. When x is 0.6, the alloy in 10mol/L H2SO4 solution's corrosion weight lessness was only 0.55 mg/cm2, which was lower two times than 304 stainless steel.
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