Study Of Preparation And Performance Of A New Type Of SiC/Cu Composite Materials

With the increase of the operating speed of high-speed rail,people have higher and higher requirements for the performance of braking materials.In recent years,threedimensional network porous ceramic / metal bicontinuous phase composites have gained widespread attention because they can retain the advantages of ceramic and metal two phases,and they are expected to become a new generation of brake materials.However,in the preparation process of composite materials,the mechanical properties of the currently fabricated ceramics are not good enough,the pore structure is defective,and the wettability of the ceramic and metal phases restricts the performance and application of this material.In order to improve the properties of composite materials,three-dimensional network SiC porous ceramics were prepared by organic foam method and 3D printing combined with gel injection molding.The effects of ceramic slurry and processing technology on the properties of three-dimensional network SiC porous ceramics were studied.A three-dimensional network SiC porous ceramic / Cubased composite was prepared by in-situ pressureless infiltration process.The effects of the composition of the metal phase,heat treatment process,and porous ceramic preparation process on the mechanical properties and thermal properties of the threedimensional network SiC porous ceramic / Cu-based composite were investigated.The main results are as follows:?1?The stability and fluidity are better with slurry with silicon carbide powder,alumina and yttrium oxide as starting materials,dispersant PAA-NH4 at 1wt%,p H 10,particle size ratio d_0.5/ d_1.5 = 0.5.The strength of SiC porous ceramic prepared by the organic foam template method reached 2.21 MPa by using the sponge pretreated with Na OH solution.?2?Using the wire PVA as the raw material,a preform with a porous structure was prepared by FDM3D printing molding technology,and then a three-dimensional network SiC ceramic porous precursor was made by a gel injection molding process.Moisture and template in the ceramic green body were removed by an integrated process of liquid drying and debinding to obtain a three-dimensional SiC porous ceramic.The solid content of the slurry prepared by this method can reach 56 vol%,and the relative density of the porous ceramic obtained after sintering is 95.53%.The ceramic density and compressive strength are 3.03 g / cm3 and 39.23 MPa,respectively.?3?The in-situ pressureless infiltration method was used to prepare a threedimensional network SiC porous ceramic / Cu-based composite material with a holding temperature at 1050°C and time at 6h by using metal alloy powder as the raw material,the addition ratio of iron powder and nickel powder at 8: 3.The compressive strength of the composite material prepared using the porous ceramic prepared by the organic foam template method is 740.61 MPa,the thermal conductivity is 220.43 W / m·K,and the relative density is 88.31%.The density,mechanical properties and thermal conductivity of the composites made using 3D printing and porous ceramics prepared by gel injection molding are 92.82%,815.33 MPa and188.97 W / m·K,respectively.