Study On Preparation And Properties Of Ceramic-based Graphite Conductive Coating

Conductive coatings have been widely used in the fields of electrode,antistatic,electromagnetic shielding,electric heating and so on.In recent years,organic polymers are often used as film-forming materials in the preparation of conductive coatings.However,organic polymers have some disadvantages such as not resistant to high temperature and easy to aging.Compared with organic polymers,ceramic coatings have more excellent heat resistance,hardness,aging resistance,corrosion resistance and so on.In order to obtain conductive coatings with high heat resistance,conductive coatings used on glass coffee table or floor tile for heating were prepared in this paper by sol-gel method using silica sol,siloxane and graphite(CGM)as main raw materials.The conductive and heat-resistant properties of the coating were improved by adding conductive fillers such as graphene(Gr)and conductive carbon black(CB).The factors and mechanism affecting the heat resistance of ceramic ink conductive coating were studied systematically,and the adhesion of the coating is also studied.The conclusions are as follows:(1)The surface tension test results show that the surface tension of the coating increases with the increase of the amount of conductive fillers.The addition of graphite,aluminum powder and graphene has little effect on the surface tension of the coating,and the coating will not appear shrinkage,cracking and shedding.But the addition of conductive carbon black has a great influence on the surface tension of the coating.If the addition of conductive carbon black is more than 7.5wt%,the coating would crack and fall off after curing and sintering.(2)The electrical conductivity of the coating increased with the increase of the amount of graphite.And when the amount of graphite is 15.0wt%,the percolation threshold is exceeded,and a conductive network is formed in the coating.The addition of graphene and conductive carbon black can greatly reduce the resistivity of the coating.And the best addition of graphene and conductive carbon black is 1.0wt% and 0.5wt%,respectively.The resistivity of 18.5CGM+1.0Gr+0.5CB coating and 13.5CGM+1.0Gr+0.5CB coating is reduced to 1.20?·cm and 1.46 ?·cm,respectively.(3)The heat resistance of the coating prepared with graphite as single conductive filler is poor,and the change rate of resistivity of 20.0CGM coating during heat treatment reached22.0%.The addition of graphene can greatly improve the heat resistance of the coating,the change rate of resistivity of 1.0Gr+19.0CGM coating during heat treatment is only 2.8%.And conductive carbon black can effectively improve the heat resistance of the coating.(4)With the increase of the amount of conductive fillers,the adhesion of the coating decreases.The 8.5CGM+1.0Gr+0.5CB coating has the highest adhesion,which is 4567.76 m N.The adhesion of the 13.5CGM+1.0Gr+0.5CB coating is 3911.62 m N.