The Research On The Preparation Of ZrB₂-based Cerment And Its Corrosion Resistance To Molten Aluminium

Aluminum and aluminum alloys is one of the most commonly used economical materials in various fields.In the production of aluminum industrial,hot dip aluminizing is a mature processing method used to improve corrosion resistence.The hot dip coating has excellent corrosion resistance,high temperature oxidation resistance and good mechanical properties,which resulting in serious economic damage caused by corrosion in atmospheric environment is greatly reduced.However,during hot dip aluminizing,the sinking roller,pull roller,guide plate and other components in the plating apparatus will be in contact with the high temperature aluminum liquid.because the aluminum liquid is extremely corrosive,and the components are easily suffered from aluminum liquid,resulting in the reduce of available life of the plating equipment.Therefore,it is desired to have a material with higher corrosion resistance to aluminum liquid used for plating device,protecting the hot diping equipment from eroded,which can effectively improve the production efficiency of factory,strengthen the quality of aluminum plating materials,and it is important for corporate profits.ZrB₂has excellent corrosion resistance,strength,hardness,anti-heat shock and other properties,so that it is studied by many scholars.But the melting point of ZrB₂is extremely high,and it is difficult to sinter at a high temperature and hard to obtain higher density.Previous researchers added a single metal material in the sintering process to reduce the sintering temperature and improve the sintering performance.This paper uses Spark Plasma Sintering(SPS),with ZrB₂powder and AlFeNiCoCr high entropy alloy powder as raw materials to prepared ZrB₂-AlFeNiCoCr composites,using XRD,EDS,SEM and other instrumentation to research the mircostructure,mechanical properties,aluminum corrosion performance in the aluminum molten and friction wear performance.This paper uses SPS sintering techniques to prepare three kinds of ZrB₂-AlFeNiCoCr composites with different contents of high entropy alloy bonded phase at 1300?,namely ZrB₂-12,ZrB₂-20,ZrB₂-30.Result shown that as high entropy alloy bonding increase,the density,hardness,and fracture toughness of the composites increase.It can be obtained from experiments that ZrB₂-30 has the best performance,its density is 88.71%,hardness 1363 HV,fracture toughness 5.26MPa·m^1/2,corrosion rate and friction wear is 4.201×10^-3mm/h and0.1137mm³respectively.To improve the density of the composite,the microstructure and performance of ZrB₂-30%AlFeNiCoCr,it sintering at higher temperature,such as 1400?to 1600?,namely ZrB₂-1400,ZrB₂-1500,ZrB₂-1600.The result shows the comprehensive performance of the composite materials obtained at 1500?is the best.However,the relatively density of the composite materials is descend caused by overheated and the external pressure of the sintered apparatus at 1600?.The relative density of ZrB₂-1500 reaches 97.71%,and the aluminum corrosion rate reaches 1.225×10^-3mm/h,and Vickers hardness reaches 1911.8 HV,The fracture toughness 6.79 MPa·m^1/2,and the amount of friction 0.104 mm³.In order to reduce the spalling of the composite material in the aluminum molten caused by the loss of the bonding phase when the sintering temperature is too high,there different contents of the second phase SiC was added to the ZrB₂-30%AlFeNiCoCr composite material,namely ZrB₂-5SiC,ZrB₂-15SiC,ZrB₂-25SiC,and as the SiC content increased,the corrosion rate of the composite in the aluminum liquid decreased.ZrB₂-25SiC composites were the lowest,which was 2.395×10^-4mm/h,the density 93.73%,the hardness 1779.5 HV,and the fracture toughness 6.59 MPa·m^1/2.The experimental results show that when the sintering temperature of the composite is1500?and AlFeNiCoCr high entropy alloy bonding phase is 30%,which has preferably density,hardness,fracture toughness,and friction and wear performance,and ZrB₂-25SiC composites have the lowest corrosion rate.