An object of the present invention is to provide a composite ceramic coating material capable of reducing fouling while having good adhesion to a metal base material of a boiler tube. The present invention is an aqueous solution of alkali silicate of 55 to 75% by weight; 20-40% by weight of heat-resistant ceramic powder; And it provides a ceramic composite coating material for a boiler tube, characterized in that it contains 1 to 5% by weight of active metal.
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