Study On Friction Wear And Corrosion Properties Of Fe₃Al Based Alloys

Wear and corrosion are the main cause of the failure of mining fully mechanery under the complex coal mining environment.It is preferred to choose materials with good wear and corrosion resistance,at the same time of to meet the requirement of coal mine machinery high abrasion resitance,lighter weight of coal mine machinery is beneficial to improvie its service life and achieve the goal of sustainable development of energy conservation and emission reduction.In this paper,the lightweight and low-cost Fe₃Al based alloy was selected as the experimental material to study its wear properties of sliding and free abrasive conditions.The uniform corrosion and electrochemical corrosion performance was also disscussed under the the simulated mine water corrosion condition.So as to provide technical support for application of Fe₃Al based alloy wear resistant components in coal mine machinery.The main conclusions of the paper are as follows:The sliding wear test proved that the friction coefficient curve of Fe₃Al based alloys increases sharply in the initial stage under different experimental conditions,and tends to be stable after a small decrease.Under the same conditions,the wear loss of Fe₃Al based alloy is lower than that of HD450 wear-resistant steel,showing better anti-sliding wear performance.During dry friction,the wear mechanism of Fe₃Al based alloy is mainly furrow and fatigue wear,and the fatigue spalling tends to be serious with increasing load.Under the friction of quartz sand,the main mechanism of wear is controlled by chisel and furrow wear.As the load increases,the chisel pits on surface deepen and the wear loss is increased.The free abrasive wear loss of Fe₃Al based alloy is lower than that of HD450 steel,and the main cause of its wear is fatigue spalling caused by chiseling and cyclic plastic deformation,which shows better anti-abrasive wear performance.The uniform corrosion test of acid,medium and alkali mines showed that the uniform corrosion weight loss and corrosion rate of Fe₃Al based alloys are lower than those of HD450wear-resistant steel in different corrosion cycles,and the corrosion rate of the acidic working condition is the largest,but also far lower than HD450 wear-resistant steel.When the corrosion cycles is 24 days,the corrosion products of the Fe₃Al based alloy are mainly FeO,FeOOH and Al₂O₃.Under acidic conditions,the early corrosion mechanism of Fe₃Al based alloys is mainly exfoliation corrosion,which gradually transitions to local pitting and corrosion trenches as the corrosion cycle prolongs.Under neutral and alkaline conditions,Al₂O₃ and Fe₂O₃ passivation films exist on the corrosion surface of Fe₃Al based alloys,and their corrosion resistance is better than that of acidic conditions.The degree of corrosion of HD450 steel is severe under three working conditions,expressed as the number of pitting pits is large and deep,and there are a lot of corrosion grooves on the corrosion surface.Electrochemical corrosion experiments show that the open circuit potential of 304 stainless steel,Fe₃Al based alloy and HD450 steel under acidic conditions is the most negative,and the working electrode is more likely to lose electrons than the reference electrode,near which corrosion is most likely to occur.The neutral corrosion potential is higher than acidic and alkaline,and the corrosion tendency is minimal.Under the three corrosive conditions,the open circuit potential of 304 stainless steel is higher than that of Fe₃Al based alloy and HD450 steel.The polarization curves have obvious passivation platform,and the corrosion resistance is better than that of Fe₃Al based alloy and HD450 steel.Under neutral and alkaline conditions,the polarization curve of Fe₃Al based alloy directly enters the passivation platform,while the HD450 steel does not have obvious passivation zone.The former has better corrosion resistance.The electrochemical equivalent circuit diagrams of 304 stainless steel,Fe₃Al based alloy and HD450 steel are consistent,and the solution resistance Rs and the resistance capacitor RpCp are connected in series.Under the same working conditions,304 stainless steel show the best corrosion resistance,which has the highest impedance value and the largest tolerance radius,followed by Fe₃Al based alloy,and HD450 has the weakest corrosion resistance.