铝磷酸盐热硬砂抗吸湿机理探讨.pdfVIP

学兔兔 铸 造 Feb．2011 · 188· FOUNDRY Vo1．60 NO．2 铝磷酸盐热硬砂抗吸湿机理探讨 夏 露，黄 晋，张友寿，董仕杰，李四年 (湖北工业大学机械工程学院，湖北武汉430068) 摘要：结合铝磷酸盐热硬砂抗吸湿性能测试，借助干扫描电子显微镜和x射线衍射仪，分析了改性剂对热硬砂抗吸湿 性能的影响，探讨了铝磷酸盐热硬砂的抗吸湿机理。结果表明：粘结膜断口形貌不同，性能差异很大，具有塑性的粘 结膜具有较高的干强度和较好的抗吸湿性。32BOM0和32BOM10粘结剂在胶凝过程中均有晶体相析出，导致粘结膜产生 相变应力，产生裂纹，使水分子易于侵入，导致强度下降。32BOM10胶凝产物中有非水溶性的MgHPO ·7H O晶体，提 高了铝磷酸盐热硬砂的抗吸湿性，32B8M15粘结剂的胶凝产物为非晶态，没有应力扩展倾向，粘结膜具有塑性，裂纹 较少。因此32B8M15热硬砂具有较高的干强度和较好的抗吸湿性。 关键词：铝磷酸盐热硬砂；抗吸湿机理；粘结膜；断口；胶凝产物 中图分类号：TG221 文献标识码：A 文章编号：1001—4977(201 1)02—0l88—04 Discuss on Humidity Resistance Mechanism of AIuminum—Phosphate Heat Cured Sand XIA Lu，HUANG Jin，ZHANG You—shou，DONG Shi-jie，LI Si—nian (School of Mechanical Engineering，Hubei University of Technology，Wuhan 430068，Hubei，China) Abstract： The effect of modifier on humidity resistance of AI—phosphate heat cured sand was analyzed by using of SEM and XRD combined with humidity resistance test，and the humidity resistance mechanism was discussed．The results reveal that the properties of heat cured sand are different because of different fracture morphology of bond membrane，and the bond membrane with plastic has higher dry strength and better humidity resistance．The crystal phase iS precipitated during ielling process of both binders 32B0M0 and 32B0M1 0，which results in the occurrence of transformation stress and crack jn the bond membrane．SO water molecule jS easy to jnfiltrate jn． and lead to decrease of compressive strength．The Mgri