| CPC C04B 41/4582 (2013.01) [C04B 38/0025 (2013.01); C04B 38/0074 (2013.01); C04B 38/08 (2013.01); C04B 41/009 (2013.01); C04B 41/455 (2013.01); C04B 41/5027 (2013.01); C04B 41/5035 (2013.01)] | 3 Claims |
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1. A coating composition comprising:
a mixture of potassium tetraborate tetrahydrate, ammonium pentaborate tetrahydrate, colloidal silica aqueous dispersion, and water, wherein heat-firing the mixture leads to a composition of K2O—SiO2—B2O3, and wherein drying and heating the composition of K2O—SiO2—B2O3 to a temperature above 600° C. forms a black refractory foam, and an additive comprising hollow borosilicate spheres or zinc oxide.
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