Preparation And Properties Of The Electro-thermal Laminated Ceramics With Carbon-based Layer

Carbon-based electro-thermal coatings with benefits of high electric conductivity,light weight,stability,and low cost show great superiority in the application of indoor heating facilities,such as electro-thermal films,as well as anti-static coating and electromagnetic/radio frequency interference shielding.In the field of indoor heat supply,the eco-friendly electro?thermal films based on conductive coating have been gradually applied to indoor heat supply in cold areas.However,the air-gap between the floor substrate and electro-thermal films causes thermal dissipation.In addition,the installation of the electro-thermal films is also a complicated procedure.In order to solve the air-gap problem and develop a new individual with high reliability and electro-thermal property at low voltages,we aimed at preparing a laminated ceramic with high thermal efficiency,aesthetics,and integrality.In this thesis,we designed a novel laminated ceramic,which was composed of thermal conduction substrate,electro-thermal component,electric-insulation,and thermal insulation.The carbon-based electro-thermal layers were the composites of conductive fillers and water-based acrylic resin matrix.Based on the successful preparation of the electro-thermal layers with high electrical conductivity,the electro-thermal laminated ceramics consisted of ceramic tile substrate,carbon-based electro-thermal layer,silicone sealant layer,and foaming ceramic layer successively were prepared.With safety,thermal stability,reliability,aesthetic surface decoration,and good electro-thermal property at low voltages,the electro-thermal laminated ceramics are highly expected to be applied to indoor heat supply.To prepare the electro-thermal layer,the carbon-based suspension was spread on the ceramic tile by tape casting.The effects of kinds and contents of conductive fillers on the electro-thermal property of electro-thermal layer were investigated and then the optimal mass ratio of graphite,carbon-black and nickel powder was obtained,which was 45.5 wt%:43.5 wt%:11.0 wt%.After that,the effects of dispersant,ball-milling parameters,and filler content on the electro-thermal property of electro-thermal layer were studied.We found that when the carbon-based suspension was mixed by ball-milling at 400 r/min for Ih and the suspension thickness was 400 ?m,the surface temperature of electro-thermal layer(20.5 cm lengthX 2 cm width),in which the content of conductive filler and dispersant was 55 wt%and 0.2 wt%respectively,was up to 119.0? achieved at an applied voltage of 36 V for 30 min.The effects of applied voltage and carbon-based suspension thickness on the electro-thermal property of the electro-thermal laminated ceramics were studied.Additionally,the effect of carbon-based suspension thickness on the interfacial adhesive strength between the ceramic tile and electro-thermal layer was characterized and analyzed.It indicated that at an applied voltage of 10 V for 30 min,the surface temperature of the electro-thermal laminated ceramics with the carbon-based suspension of 1.0 mm was 40.3 °C,which was available for indoor heat supply.Furthermore,the temperature distribution on the surface of laminated ceramics was quite uniform.The adhesion strength of the electro-thermal layer with the carbon-based suspension thickness of 1.0 mm was 1.02 MPa with the failure mode of cohesive failure.A comparative study of adhesive strength and volume resistivity during thermal aging at 100?was conducted to analyzed the thermal stability of the laminated ceramics.It can be found that the adhesive strength of electro-thermal layer decreased slightly and the volume resistivity showed little increase,indicating that the electro-thermal laminated possessed good thermal stability and reliability.