铝磷酸盐热硬砂抗吸湿机理探讨.pdf

Feb.2011
FOUNDRY
Vof. 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
(胡北工业大学机械工程学院,湖北武汉430068
摘要:结合铝磉酸盐热硬砂抗湿性能测試,借助于扫描电子显徽镜和ⅹ射衍射仪,分析了改性剂对热硬砂抗吸湿
性能的影响,探计了礤酸盐热硬砂的抗吸湿机理。结果表明:魅结膜新口形媲不同,性能差异很大,具有窒性的粘
结膜具有较高的于强度和较好的抗湿性。32BOMO和32BOM!O粘剂在胶凝过程中均有晶体相析出,导致粘结膜产生
相変应刀,严生裂纹,使水分子易于侵入,导致强宬下降:32BOM胶疑产物中有非水溶性的 Mghpc7H1O最体,提
高了钯盐热硬砂的抗吸湿性,32B8M1S料结剂的胶懸产物为非晶恋,没有力扩展侦向,粘结膜有塑性,裂纹
较少。因此32B8MI5拡硬砂具有较高約干度和较好的抗藩性
关键词:铝磷酸盐热使砂;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(2011〉02-0188-04
Discuss on Humidity Resistance Mechanism of
Aluminum-phosphate Heat Cured Sand
XIA Lu, HUANG Jin, ZHANG You-shou, DONG Shi-jie, LI Si-niar
School of Mechanical Engineer ng, Hubei Uniersity of Technology, Wuhan 430068, Hubei, China
Abstract: The effect of modifier on humidity resistance of Al-phosphate heat cured sand was
analyzed by using of SEM and XRD combined with humidity resistance test, and the humidity
esistance 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 jelling process of both binders 32B0M and 32B0M10, which results in the occurrence of
transformation stress and crack in the bond membrane, so water molecule is easy to infiltrate in,
and lead to decrease of compressive strength. The Mghpo, 7H2O crystal in the gel products of
binder 32B0M10 is water insoluble, so it can improve humidity resistance of Al-phosphate heat
cured sand. Gel producf of binder 32B8M15 is amorphous, there is no tendency of stress extension
and becasue the bond membrane is plastic, fewer cracks can be found. o 32B8M15 heat cured
sand has higher dry strength and better humidity resistance
Key words: Al-phosphate heat cured sand; humidity resistance mechanism; bond membrane
fracture; gel products
水玻璃粘结剂无毒、无味,但水玻璃砂的溃散性行了大量的试验,本文将在试验基础上对铝磷酸盐
和再生性差。从20世纪80年代以来,为寻求水玻璃替代热硬砂抗吸湿机理进行探讨,为解决其抗吸湿性提
品,国内外许多铸造下作者把眼光聚集倒僯酸盐粘结供理论依据
剂上,作为一种新型无机粘结剂,具有水璃粘结
剂的低碳环保特性,同时还具有好的溃散性和再尘
试验用材料、设备及方法
生-,曾一度得到人们的青眯,但真正到工厂应用,1.1试验材料
却发现许多间题。就热硬砂而言,最大的间题是抗
T.业磷酸(85%),氢氧化铝,含镁改性剂,含硼
吸湿性很差,特别是夏天在浙江沿海一带,这个问改性剂,原砂为福建东海砂(S0/100,圆形,SiO含
题更明显。课题组曾带着同样的样品分别耷赴浙江.、量>88%,含泥量<1.0%)。
河北、北京等地铸造企业试用,在北京的铸造厂成1.2试验用仪器及设备
用效果很好,而在浙江台州,却发现制好的砂第
DZTW型调温电热套及三口反应総(配
二天便吸湿坍塌了。为解决抗吸湿问题,课题组进DJIC100vV増力定时电动搅拌器),SHY-A叶片式混
基金项目:湖北俏科技厂自然科学基金项日(2009CD297),收稿日期:2010
到初稿,2010-08-25收到修订稱
作者筒介:夏露(1971-),女,硕土,副教授,主要从卡造型材料及金属基复合材料研究。E-mait:xi91956c726.com