Study On Rheological Properties And Corrosion Properties Of Rare Earth Cerium And Graphene On Al-Si Alloy

With the rapid development of modern industry and increasing environmental pollution,acid rain weather has formed in many parts of the world.In addition,in marine industrial applications containing chloride ions,aluminum-silicon alloys require not only higher mechanical properties,but also better corrosion resistance.In this paper,the effects of rare earth cerium and graphene on the rheological and corrosion properties of aluminum-silicon alloys are mainly studied through microanalysis techniques,rheological experiments and corrosion performance tests.The structure of the ZL101-1.0Ce semi-solid slurry prepared by the ultrasonic vibration method is more uniform,finer and rounder than that of the untreated slurry,and the average grain size of the primaryα-Al phase is about 32μm.The apparent viscosity of semi-solid ZL101-x Ce（x=0,0.5,1.0,1.5,and 2.0 wt.%）slurry increases with the increase of cerium addition.When the ultrasonic power increases,the apparent viscosity of the semi-solid ZL101-x Ce material gradually decreases.As the solid fraction increases,the apparent viscosity of the semi-solid slurry increases exponentially.When the addition amount of cerium is less than 1.0 wt.%,the addition of rare earth cerium has two effects on ADC12 alloy.On the one hand,the cathode phase（eutectic Si phase andβ-Al5Fe Si phase）in the alloy can be refined to form a"large anode and small cathode"micro-galvanic corrosion,thereby improving the corrosion resistance of the alloy.On the other hand,the formation of the Al-Si-Cu-Ce cathode phase accelerates the corrosion of the alloy.When the addition amount of cerium is1.5 wt.%,the coarse cathode phase forms the micro-galvanic corrosion of"large cathode and small anode"in the alloy,which accelerates the corrosion.The electrochemical results show that compared with the base alloy,the corrosion resistance of ADC12-1.0Ce alloy is greatly improved.Its corrosion potential is-628m V.Its corrosion current density is 8.4μA·cm^-2,which is about 17%of the base alloy.The results of the immersion test show that the corrosion resistance of ADC12-1.0Ce alloy has been significantly improved compared with the ADC12matrix.The corresponding corrosion rate measured by the weight loss method is about 28%of that of the untreated alloy.The addition of graphene can effectively refine the cathodic Si phase in ADC12alloy,forming a"large anode and small cathode"micro-current corrosion,thereby improving the corrosion resistance of the alloy.The ADC12-0.9GNPs alloy have a smaller grain size,about 32.6μm.The results of electrochemical and immersion tests show that the corrosion potential of ADC12-0.9GNPs alloy in 0.1 mol·L^-1hydrochloric acid solution is-539 m V,and its corrosion current density is 1.08m A·cm^-2,which is about 38%of ADC12-0.3GNPs alloy.The results of weight loss and hydrogen evolution tests show that the weight loss corrosion rate of ADC12-0.9GNPs alloy is 52.6%lower than that of ADC12-0.3GNPs.The hydrogen evolution corrosion rate of ADC12-0.9GNPs alloy is 57.2%lower than that of ADC12-0.3GNPs.