【作者】 赵伟；

【导师】 范志康；

【作者基本信息】 西安理工大学 ， 材料加工工程， 2007， 硕士

【摘要】 本文研究了以硅溶胶为粘结剂，氧化锆为耐火材料来制备氧化锆／石墨复合型芯的制备工艺；并分析了金属颗粒作为冷却剂在金属凝固过程中应用的可行性、金属颗粒的冷却能力以及金属颗粒作为辅助冷却剂在定向凝固的液态金属冷却法中的应用，得出以下结论：（1）以硅溶胶为粘结剂，氧化锆为耐火材料来配制涂料，采用刷涂石墨型芯的方法来制备的氧化锆／石墨复合型芯经800℃和1000℃实际浇铸实验，结果证明型芯的强度足够满足实际浇铸要求。（2）型芯制备的工艺为：氧化锆涂料的粉液比1：3.0～3.5，粘度控制为13～20×10^-6m²／s，密度2.0～2.5g／cm³；涂层层间干燥参数温度22～25℃，湿度45％～60％；型芯的最佳焙烧工艺为焙烧温度1000℃，保温时间2小时。（3）在金属凝固过程中用固态金属颗粒作为冷却剂能加快金属的冷却速度，用固态金属颗粒作为冷却剂是可行的。（4）熔点低的金属颗粒作为冷却剂的冷却效果优于高熔点的金属颗粒；在加入的冷却剂完全熔化的条件下，加入的金属颗粒越多，金属的冷却速度越快，冷却效果越明显。（5）金属颗粒作为辅助冷却剂应用于液态金属冷却法中，不但能加快金属的冷却速度，而且能有效地降低液态金属冷却剂的温度，从而增加液态金属冷却剂的作用时间；而且加入的颗粒越多，金属的冷却速度越快，液态金属冷却剂上升的温度越小，冷却剂的作用时间越长。更多还原

【Abstract】 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.更多还原