HOLE SEALING AGENT AND HOLE SEALING METHOD OF SPRAY COATING LAYER

摘要

PURPOSE: A hole sealing agent and a hole sealing method of spray coating layer are provided, in which floating dross and zinc are not stuck together well by using a composition comprising boron nitride and colloidal silica in sealing holes using a metal alkoxide solution. CONSTITUTION: 1 to 6 wt.% of boron nitride powder is added to a solution consisting of 10 to 70 vol.% of metal alkoxide, 5 to 70 vol.% of alcohol, 0 to 70 vol.% of water, and 0 to 85 vol.% of colloidal silica in a hole sealing agent of spray coating layer formed on a member which is used with dipped in molten metal. A hole sealing method of spray coating layer comprises the process of heat treating the hole sealing agent coated spray coating layer at the temperature range of 100 to 500 deg.C after coating a hole sealing agent which is formed by adding 1 to 6 wt.% of boron nitride powder to a solution consisting of 10 to 70 vol.% of metal alkoxide, 5 to 70 vol.% of alcohol, 0 to 70 vol.% of water, and 0 to 85 vol.% of colloidal silica on the spray coating layer in a method of dipping, brushing or spraying. The spray coating layer is an oxide based spray coating layer comprising 50 wt.% or more of one or more oxides selected from the group consisting of aluminum oxide and zirconium oxide, and a balance of one or more oxides selected from the group consisting of silicon oxide, yttrium oxide, cerium oxide, calcium oxide, and magnesium oxide.