NEW TYPE OF CERAMIC COMPOSITE FILMS COATED ON STEEL BY WET PROCESS

摘要

A ceramic coating slurry was designed, which suspended or dissolved ceramic components(silica, titania, alumina and kaolinite)and glass-forming components (alkali silicates and soda ash) in water. SiO_2-Al_2O_3-TiO_2 based composite films (about 100 μm thick) were deposited on a steel plate by coating the slurry with a brush, followed by drying and calcination. The ceramic coatings obtained under proper conditions were found to exhibit excellent stability over a wide range of temperature between 1100℃ and-196℃ as well as to thermal shocks between 600℃ and room temperature. As evaluated by copper electrodeposition method, through-holes were present in the coatings calcined at 700℃ or below, while they were eliminated completely after calcination at 1100℃ in N_2. Vickers hardness of the coatings increased with increasing calcination temperature, while adhesive strength went through a sharp maximum at 800℃.