含短切玻璃纤维的水玻璃精铸涂料的流变性

摘要

The short glass fibers were introduced into the slurries by 0%‐0 .5% (mass fraction of re‐fractory powders) for preparation of fiber‐reinforced shells for investment casting .The rheological properties of coatings containing different amounts of glass fibers were measured by R/S rheometer and the rheological behaviors of coatings w ere investigated .T he results show that the apparent viscos‐ities of coatings containing different amounts of glass fibers decrease with increasing shear rate ,i .e ., shear thinning behavior ,similar to that of the coating without fibers .At the same shear rate ,the ap‐parent viscosities of coatings containing fibers are higher than that of the coating without fibers and the apparent viscosities of coatings containing 0 .3% (mass fraction) fibers are higher than that of the others .The high shear viscosities of coatings containing fibers increase initially ,but later decrease , with increasing amount of fibers .The high shear viscosity of the coating containing 0 .3% fibers rea‐ches a maximum value of 102 .6 × 10-3 Pa · s ,increased by about 31 .9% ,in comparison to the coating without fibers .And this coating with a maximum thixotropical loop area value of 11 .8Pa · s-1 exhib‐its an excellent thixotropical behavior .However ,it is not found that there is a noticeable effect of the amount of glass fibers on the yield stress or suspensibility of coatings .%将占耐火粉料0％～0．5％（质量分数）的短切玻璃纤维加入到制壳用涂料中，配制纤维增强水玻璃型壳用涂料。采用R／S流变仪测试不同纤维加入量条件下涂料的流变性，研究短切玻璃纤维加入量对涂料流变性的影响规律。结果表明：含纤维涂料的表观黏度随着剪切速率的增大而逐渐减小，且均具有剪切稀化的特性，其变化规律与不含纤维的涂料相似。含纤维涂料表观黏度值均高于不含纤维涂料；在相同剪切速率下，含0．3％纤维的涂料表观黏度值均高于其他涂料。随着短切玻璃纤维加入量的增大，涂料的高剪黏度值先增加后减小。含0．3％短切玻璃纤维涂料的高剪黏度值最大，约为102．6×10－3 Pa · s ，比不含纤维的涂料增大约31．9％；且该涂料的触变环面积达到最大值11．8Pa · s－1，触变性好。未发现短切玻璃纤维的加入对涂料的屈服值及悬浮性有显著影响。