Aqueous boron nitride coating capable of binding at low temperature and being used at high temperature

Abstract

The invention discloses an aqueous boron nitride coating capable of binding at a low temperature and being used at a high temperature. The coating is prepared from 15-60 wt% of hexagonal boron nitride, 2-15 wt% of a composite high temperature binder, 1 wt% of carboxymethyl cellulose, 0.5 wt% of a thickener, 1 wt% of cobalt aluminate, 0.2 wt% of isooctanol, and the balance is demineralized water. Apreparation method of the coating comprises the following steps: mixing and stirring carboxymethyl cellulose used as a dispersant, the high-temperature binder, the thickener, cobalt aluminate used asa high-temperature pigment and demineralized water at a normal temperature to form a uniform solution, adding the hexagonal boron nitride and isooctanol used as a defoamer to the solution, and performing stirring until a uniform system is formed. The coating adopts an aqueous system, has no harmful substance volatilization during use, is clean and environmentally friendly, has good adhesion, anddoes not crack or spall in order to effectively block direct contact between a metal melt and the surface of a refractory material. Additionally, the coating has excellent stability and suspension capacity, and the stability and the suspension capacity do not change under high dilution.

Description

technical field [0001] The invention relates to the technical field of metal and alloy casting, in particular to a water-based boron nitride coating that can be bonded at low temperature and used at high temperature. Background technique [0002] Due to the wetting effect between the molten metal (aluminum, copper, magnesium, zinc, etc.) and the refractory material, after the casting is completed, the solidified residual metal liquid will be firmly bonded to the refractory material on the inner wall of the filter box, launder, and crystallization tray Together, when cleaning the residual metal material, it often leads to the shedding and damage of the refractory material, which reduces the service life of the equipment, increases the labor intensity of the workers, and increases the production time. On the other hand, the small particles of refractory materials that fall off enter the metal melt, which reduces the purity and surface finish of the metal melt and reduces the p...

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Problems solved by technology

[0004] However, due to reasons such as technical secrecy, there are very few patent applications for the preparation method of boron nitride coatings, such as invention patents CN107201066A, CN103708843A, etc. Although the above-mentioned patents have prepared boron nitride coatings, the preparation method steps are loaded down with trivial details, and the bonding temperature is relatively high. high

For example, the invention patent CN107201066A needs to be dried at 700~720°C after painting; the invention patent CN103708843A needs to be heated multiple times and must be heated to 1600°C under nitrogen protection before use, which limits the application of boron nitride coatings in actual production. scope

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