| Zirconia/graphite compound mold core was prepared by the coating, in which the silicon sol was used as binder and zirconia was used as refractory materials. The application feasibility of metal particles as a coolant in the solidification process was studied, and the application of metal particles as subsidiary coolant in the liquid metal cooling of directional solidification were analyzed and studied in this investigation. The conclusions can be drawn as follows:1) The zireonia/graphite compound cores fabricated by brushing coating which was prepared by making silicon sol agglutinated zirconia as a refractory material were casteded at 800℃and 1000℃respectively, and the results show that the strength of the mold core is strong enough to meet the requirement of practical casting.2) Preparation technology of the mold core includes the following parameters: the ratio of powder and slurry is 1:3.0～3.5, the viscosity is 13～20×10-6m2/s, the density is 2.0～2.5g/cm3; the room temperature is 22～25℃and the humidity is 45%～60%; the optimum firing parameter is 1000℃holding for 2h.3) The metal grains can be used as a coolant to enhance the cooling rate during the solidification, so it is feasible to choose metal grains as a coolant.4) The cooling effect of metal grains with low melting point is better than that of metal grains with high melting point. It have better cooling effect when added more metal grains which have higher cooling rate when the added coolant completely melted.5) Metal grains as subsidiary coolant can not only enhance the cooling rate of metal, but also decrease the temperature of liquid coolant and can prolong the affect time of liquid metal. With increase of grains addition, the cooling rate increases; the affect time became longer when the temperature of liquid metal became less.
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