| 摘要 |
<p>A composition for marking or for use as an anti-scaling coating on metal products includes solids of 30 to 50 parts by weight pigment, 43 to 58 parts by weight water soluble alkali metal silicate binder, at least 50 percent of which is sodium silicate and in which the ratio of silicate to alkali metal oxide is 2.60 to 3.25, and sufficient cross-linking binder to provide 1.5 to 5.0 parts B2O3, the weight ratio of total pigment to total binder being 0.50 to 1.0. The composition adheres when applied to metal products which are at temperatures of at least 250.degree.F (121.degree.C) or which are subsequently heated to such temperatures. A preferred method of making the composition includes mixing first and second soluble alkali metal silicate solutions. The cross-linking binder is added to one of the solutions prior to addition of the other solid materials. Utilizing the two starting solutions provides a final mixture having a lower viscosity than when a single soluble silicate starting solution of equivalent SiO2 ratio is used.</p> |
