陶瓷-尼龙复合纤维含量对石膏铸型性能和微观形貌的影响

Effect of ceramic-nylon composite fiber content on properties and micromorphologies of gypsum mold

向石膏粉料中添加不同含量陶瓷-尼龙复合纤维制备石膏铸型试样,测试分析陶瓷-尼龙复合纤维交织强化石膏试样的性能并观察其断口,研究陶瓷-尼龙复合纤维含量对石膏铸型性能和微观形貌的影响。结果表明,陶瓷-尼龙复合纤维含量对石膏铸型性能影响显著,随着陶瓷-尼龙复合纤维含量增加,石膏试样生胚抗弯强度呈倒V字形变化趋势,焙烧后的抗弯强度变化不大;石膏试样透气率随陶瓷-尼龙复合纤维含量的增加而增大,当石膏混合料中陶瓷-尼龙复合纤维质量分数为1.25wt%时达到最大值32.3,与传统石膏铸型相比,增大近21倍,尼龙纤维焙烧后形成的孔洞提高了石膏铸型透气率,陶瓷纤维保留在基体中提高强度,当陶瓷-尼龙复合纤维质量分数大于0.75wt%时,纤维会团聚并割裂基体;导热性和抗热震性随陶瓷-尼龙复合纤维含量的增加而先增大后减小,当陶瓷-尼龙复合纤维含量为0.75wt%~1wt%时,导热性和抗热震性相对最佳。

Gypsum mold samples were prepared by put different contents of ceramic-nylon composite fibers into gypsum slurry. The properties and fractures of the ceramic-nylon composite fibers reinforced gypsum mold samples were tested and analyzed. The effect of the composite fiber content on the properties and microscopic appearance of gypsum mold was studied. The results show that the composite fiber content has a significant effect on the properties of gypsum mold. With the increase of the composite fiber content, the flexural strength of gypsum samples has an inverted V-shape, and the flexural strength after calcination does not change much. The gas permeability of gypsum samples increases with the increase of the composite fiber content. When the mass fraction of the composite fiber in the gypsum mixture is 1.25 wt%, the gas permeability reaches maximum of 32.3, which is nearly 21 times higher than that of traditional gypsum molds. The pores formed after the roasting of the nylon fiber increase the gas permeability of the gypsum mold, and the ceramic fiber remains in the matrix to increase the strength. When the fiber content exceeds 0.75 wt%, the fiber agglomerates and splits the matrix. The thermal conductivity and thermal shock resistance increase first and then decrease with the increase of the composite fiber content. When the fiber content is 0.75 wt%-1 wt%, the thermal conductivity and thermal shock resistance are relatively optimal.