Preparation Of Fe-si Intermetallic Compounds And Resistant To Liquid Aluminum Corrosion, Thermal Shock Resistance Research

Hot dip zinc/aluminum-plating is one of the most economic and effective protecting technologies in steels' corrosion protection in natural environment currently. However, molten zinc/aluminum has strong corrosive nature on related equipments. Nowadays, with internal heat hot dip plating oven being increasingly popularized, it is meaning to invent an internal heat protecting thimble with low cost, perfect property, large scale and longevity. In order to produce this kind of thimble, we fabricated pure Fe-Si intermetallic compound successfully by mechanical alloying and annealing treatment. In addition, we mixed alloyed powders with silicate binders with high thermal stability proportionally before mould pressing. Then we researched the corrosion resistance of different Fe-Si intermetallics with different phases in molten aluminum under different temperatures and different times. As well as compared thermal shock resistance of SiC sintered pipes with thimbles fabricated of different silicate binders in molten aluminum in addition to analyzed fractography by means of scanning electronic microscopy and density testing.The results show that: Pure Fe-Si intermetallics can be successfully fabricated by mechanical alloying with annealing treatment, and the best technical parameter is mechanical alloying 20h with temperature 950℃ and heat preservation 2h. Though felt degree between powders and stainless steel balls or spherical tanks reduced after dispersant was added in, period of Fe-Si intermetallics formed postponed largely under the same annealing treatment condition.The thimble Fe₅₀Si₅₀ (wt %) has the best corrosion resisting property in molten aluminum; pipe SiC prepared by CIP and sintering process is next and sample Fe₇₅Si₂₅ (wt %) is the worst. Though the corrosion resistance weakened with the temperature of molten aluminum rose, the sample Fe₅₀Si₅₀ (wt %) still has a good resistance after 96h corrosion in molten aluminum under 950℃. The root cause is the low density which results in large amount of lacunas exist in either interior or exterior of thimble as well as corrosion.