| 摘要 |
PROBLEM TO BE SOLVED: To form a ceramic composite coating having a photocatalytic effect on a substrate by carrying out a spark discharge while suspending titanium dioxide particles in an aq. electrolytic bath contg. a water-soluble or colloidal silicate and/or an oxyacid salt. SOLUTION: A water-soluble or a colloidal silicate is, e.g. a sodium silicate or a water-dispersible colloidal silica. An oxyacid salt is, e.g. a tungstate or a stannate. An amine salt such as an ammonium salt may further be used in the electrolytic bath besides an alkali metallic salt so as to produce a higher photocatalytic effect. Titanium dioxide particles are preferably anatase type titanium dioxide particles having 5 nm to 100μm average particle diameter. The photocatalytic effect of a formed coating can further be enhanced by immersion in ion exchanged water at 80-100 deg.C for >=5 min as post-treatment.
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