Study Of The Preparation And Performance Of The SiC/PF Composite Materials

The world wide research on conductive composite materials which are mostly in the polymer matrix,using carbon black or metal particles as conductive filler.Although this kind of composite materials has the advantages of low density,better corrosion resistance,easy processing,easy to get raw materials,the synthesis method is simple,but the polymer itself has low strength,thermal conductivity and high temperature resistant performance is poor.With the development of aviation,automobile and other requirements,many countries have developed a batch of high performance reinforced materials such as carbon fiber,silicon carbide fiber,and using metal and ceramics,high performance resin as matrix,to make advanced composite materials(ACM).This paper use SiC as the matrix,with PF as the adhesive,and using such as carbon black as conductive filler,to study the factors of affecting composition ratio,preparation process,the mechanical and electrical properties of SiC/PF composites,to assess the temperature impact,corrosion resistance and other properties.The results show that:(1)When molded of 200MPa,PF content is 22.5wt%insides,and cured in 175℃,the SiC/PF composites is best;The appropriate particle size distribution can reduce the porosity of composite materials,increase its strength;when the fine SiC is 100wt%or coarse(200#)/fine(0.5μm)is 70/30 has good comprehensive properties.(2)The conductivity and strength of the composite materials is better when filled with carbon black;when the content of carbon is less than 7.5wt%,the change of strength of the composite materials is not very obvious,but when the content of carbon is higher than 7.5wt%,the strength of the composite materials has fallen sharply.(3)With the increase of the content of carbon black,the volume resistivity of the composite materials decreases gradually.when 4.0wt%,volume resistivity has the maximum change,as the percolation threshold of the system.(4)Industrial application tests show that:with the increase of using pressure,the resistance of composite materials is reduced;Composite materials’ resistivity stability is strong,and not under the control of the load voltage;Composite materials has excellent corrosion resistance,and can be long-term work under the condition of acid and alkali;Composite materials’ cold resistance is good,the resistance decreases with the increase of temperature,and showing a negative temperature effect;The maximum using temperature of composite materials is about 400℃.