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报道了用溶胶-凝胶法在黄铜基底上制备SiO_2非晶薄膜涂层的涂膜工艺及SiO_2非晶涂层对Al-12.5％Si合金过冷度和组织的影响。结果表明:在黄铜基底上获得均匀溶胶-凝胶膜的合适工艺是溶胶中水和酒精与硅酸乙酯的摩尔比均应大于7～8,溶胶中盐酸的摩尔分数浓度不超过6×10~(-4),金属基底在溶胶中浸清后的抽出速度不大于5×10~(-3)m/s。金属基底上凝胶膜转变为玻璃膜的完成温度为360℃SiO_2非晶涂层对Al-12.5％Si合金过冷度和组织的影响取决于合金的熔液状态。合金液过冷倾向较小时,非晶涂层对合金的过冷度和组织不产生明显影响;合金液过冷倾向较大时,非晶涂层能使合金的过冷度增大,使合金的组织细化。
The coating process and the effect of SiO_2 amorphous coating on the undercooling degree and microstructure of Al-12.5% Si alloy prepared by sol-gel method on a brass substrate were reported. The results show that a suitable process for obtaining a uniform sol-gel film on a brass substrate is that the molar ratio of water to alcohol and ethyl silicate in the sol should be greater than 7 to 8 and the molar concentration of hydrochloric acid in the sol does not exceed 6 × 10 ~ (-4), the extraction speed of the metal substrate in the sol after immersion is not more than 5 × 10 -3 m / s. The transition temperature of the gel film on the metal substrate to the glass film is 360 ° C. The effect of the SiO 2 amorphous coating on the undercooling and microstructure of the Al-12.5% Si alloy depends on the melt state of the alloy. When the overcooling tendency of the alloy liquid is small, the non-crystalline coating has no obvious effect on the undercooling and microstructure of the alloy. When the overcooling tendency of the alloy liquid is large, the undercooling of the alloy can increase the degree of undercooling of the alloy, Tissue refinement.