To improve fire proofing characteristics of protective coating using ternary soluble silicate from two component mixture, the method of reducing solubility, increasing intumescence and protection time have been studied. Intumescence and solubility of ternary silicate mixtures were dependent on many kinds of water release and the strength of cation cross-links between polysilicate particles. Especially the effect of additive, for example, corn starch was investigated. However the solubility of ternary mixture is decrease in order of Na$^{+}$ >K$^{+}$ >Li$^{+}$, and the magnitute of intumescence is increased $K^{+}$ >Na$^{+}$ >Li$^{+}$.}$</TEX> +/.