【目的】解决外冷铁 -砂型与铸件界面易出现的黏砂、熔铁及清理困难等问题。【方法】以铝矾土 -白刚玉为复合耐火骨料，采用“插层 -接枝”两步法对锂基膨润土进行复合改性制备悬浮剂，结合酚醛树脂 -聚乙烯醇缩丁醛（ PVB）复合黏结剂与工业乙醇溶剂，开发一种专用于外冷铁 -砂型铸造的醇基涂料。通过正交试验系统探究了复合改性悬浮剂加入量、耐火骨料级配及黏结剂配比对涂料性能的影响，结合极差分析与权重归一化法确定最优配比。【结果】最优涂料的 24 h悬浮率达 95%，发气量为 12. 6 mL/g，涂挂性等级为 Ⅰ级，涂层耐磨性优异。生产验证显示，该涂料应用于 30 t机床床身铸件冷铁面后，铸件表面粗糙度 Ra为 12. 5 μm，黏砂面积<2%，无明显气孔（ Φ>2 mm）及熔铁现象，表面清洁时间显著缩短，铁块回收利用率大幅提升。【结论】该研究为外冷铁激冷工艺中涂料的优化提供了有效解决方案。

［Objective］To address issues such as sand adhesion，metal penetration，and cleaningdifficulties that commonly occur at the interface between sand molds with external chills and castings.［Methods］A suspension agent was prepared by composite modification of lithium based bentoniteusing a two-step method of "intercalation grafting" with bauxite white corundum as the composite refractory aggregate. The coating was formulated by combining a composite binder consisting of phenolic resin and polyvinyl butyral（PVB） with industrial ethanol as the solvent. Orthogonal experiments were carried out to systematically investigate the effects of the composite-modified suspending agent content，refractory aggregate gradation，and binder ratio on the coating properties. Theoptimal formulation was determined through range analysis and weight normalization.［Results］The results showed that the optimized coating achieved a 24 h suspension rate of 95%，a gas evolution value of 12. 6 mL/g，a brushing performance grade of Class Ⅰ，and excellent wear resistance. Production validation on 30-ton machine tool bed castings indicated that the chill surface coated with thedeveloped formulation exhibited a surface roughness（Ra）of 12.5μm，a sand adhesion area of less than 2%，and no obvious pores（Φ>2 mm）or metal penetration. Additionally，the surface cleaning time was significantly shortened，and the recovery rate of chills was greatly improved.［Conclusion］This study provided an effective solution for optimizing coatings used in the external chill chilling process.