水玻璃砂改性剂的研制及其对水玻璃砂性能的影响

发布时间：2018-03-20 21:42

  本文选题：改性剂　切入点：CO_2　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：水玻璃作为砂型铸造的粘结剂能够减少铸造工业污染,实现绿色铸造,符合我国目前的绿色发展理念。但是,在水玻璃砂使用过程中,一直存在如水玻璃加入量高、型(芯)溃散性差等问题,因此,研制水玻璃砂改性剂,通过添加改性剂改善水玻璃砂的力学性能具有重要意义。本文采用CO_2硬化水玻璃砂的砂型铸造工艺,首先选取Al_2O_3、ZrO_2、Si_3N_4作为无机物改性剂的主要成分,研究无机物对水玻璃砂性能的影响,确定其成分配比、加入量和无机物粉末粒度;选取十六烷酸甲酯、硬脂酸甲酯、邻苯二甲酸二辛酯、芥酸酰胺、二十烷醇和环己酮作为有机物改性剂的主要成分,研究有机酯(十六烷酸甲酯、硬脂酸甲酯、邻苯二甲酸二辛酯)对水玻璃砂性能的影响,以及酰胺、醇、酮对有机酯改性效果的影响,并借助XRD、SEM、EDS等分析手段分析改性原理。研究结果表明,当添加水玻璃6%(占砂重),加入无机物改性剂1.5%(占砂重),Al_2O_3、ZrO_2、Si_3N_4的成分配比为1.5:1:0.67,粒度为1~50μm时,改性效果较好。制备的水玻璃砂试样的即时强度、24h强度和800℃残留强度分别为1.26MPa、2.64MPa、6.67MPa,比只添加6%水玻璃的试样即时强度提升174%、24h强度提升38%、800℃残留强度降低42%。加入Al_2O_3、ZrO_2、Si_3N_4粉末的同时,加入占水玻璃含量2%的硬脂酸甲酯、6%的十六烷酸甲酯、4%的邻苯二甲酸二辛酯,可将水玻璃加入量降低至3%,并能很大程度的改善水玻璃砂性能,制备的水玻璃砂试样即时强度、24h强度和800℃残留强度分别为0.65MPa、2.77MPa、2.83MPa,试样的发气量为13.7ml/g。加入Al_2O_3、ZrO_2、Si_3N_4粉末的同时,加入3%水玻璃,以及占水玻璃含量10%的有机酯、1%的芥酸酰胺、2%的环己酮,制备的水玻璃砂试样的即时强度、24h强度和800℃残留强度分别为0.72MPa、2.79MPa、1.62MPa,试样的发气量为11.7ml/g。该种改性剂能够在保证砂型具有很好的即时强度和24h强度的同时降低其残留强度,有效改善了水玻璃砂的溃散性,且发气量低,符合水玻璃砂型(芯)在生产中的要求。通过XRD、SEM、EDS分析表明,加入的改性剂弥散分布于水玻璃粘结剂中,提高了砂型即时强度和24h强度;试样在800℃加热30min和随炉冷却过程中,无机物粉末由于线膨胀系数小在砂粒表面和粘结桥上起到割裂作用形成裂纹,有机物充分挥发,导致砂粒间粘结桥上形成大量的气孔,导致砂型的残留强度大幅度降低。本课题研制的水玻璃砂改性剂成分如下:无机物Al_2O_3、ZrO_2、Si_3N_4成分配比为1.5:1:0.67,加入量占砂重1.5%;有机物十六烷酸甲酯、硬脂酸甲酯、邻苯二甲酸二辛酯、芥酸酰胺、环己酮的加入量分别占水玻璃加入量的5%、1.67%、3.33%、1%、2%。
[Abstract]:As a binder of sand mold casting, water glass can reduce the pollution of casting industry and realize green casting, which is in line with the present green development idea in China. However, in the process of using sodium silicate sand, there is always a high amount of sodium silicate. Therefore, it is of great significance to improve the mechanical properties of sodium silicate sand by adding modifier to improve the mechanical properties of sodium silicate sand. In this paper, the sand mold casting process of CO_2 hardened sodium silicate sand is adopted. First, we select Al2O3ZrO2Si3NSP 4 as the main component of the inorganic modifier, study the effect of inorganic matter on the properties of sodium silicate sand, determine the composition ratio, the amount of addition and the particle size of inorganic powder; select methyl hexadecanoate, methyl stearate, The effects of organic esters (methyl hexadecanoate, methyl stearate, dioctyl phthalate) on the properties of sodium silicate sand were studied. The effects of amides, alcohols and ketones on the modification of organic esters were analyzed by means of XRDX SEMEDS. When adding water glass 6% (weight of sand, adding inorganic modifier 1.5), and adding Al2O3ZrO2Si3NSP, the composition ratio of the structure is 1.5: 1: 0.67, and the particle size is 50 渭 m, and the ratio of composition is 1.5: 1: 0.67, and the particle size is 50 渭 m, when the proportion of the components is 1.5: 1: 0.67 and the particle size is 50 渭 m. The instant strength and the residual strength at 800 鈩，

本文编号：1640907