聚合物预涂层对冷轧搪瓷钢密着性与表面性能的影响

Influence of Polymer Precoating on Adherence and Surface Properties of Enameled Cold-rolled Steel Sheet

目的考察5种不同类型树脂作为搪瓷用冷轧钢板预涂层对最终搪瓷钢制品性能的影响。方法在相同基板条件下,利用刮棒进行湿法涂覆后加热固化法,制备具有相同单位膜重的5种不同树脂的预涂层冷轧搪瓷用钢。采用静电喷涂将瓷釉粉末均匀散布于预涂层冷轧搪瓷用钢表面,再在马弗炉中烧结成搪瓷钢片。通过落锤测试和表面显色法分析搪瓷钢片的搪瓷密着性能和表面针孔率。结果与无涂层冷轧搪瓷用钢相比,所选的预涂层树脂都能不同程度地提高搪瓷层的密着性能,但不同树脂在高温下的热分解速率差异以及温度高于650℃后的热分解残留物的不同,会直接影响搪瓷层表面的针孔缺陷。经测试,最优性能的预涂层可以将搪瓷的密着性能由无涂层的5级提升到1级,表面针孔率在薄搪瓷层的条件下控制在200个/m2以下。结论通过对冷轧搪瓷钢板表面施加聚合物预涂层,可以有效提高搪瓷钢制品的密着性能。选择综合性能优良的预涂层树脂匹配合适的搪瓷层厚度,可以减轻或避免由预涂层热分解引起的表面针孔缺陷。

The work aims to investigate effects of five different resins as preeoatings of cold-rolled steel sheet for enameling use on properties of final enamel steel products. Five different precoating films of identical unit fill weight were deposited on same kind of steel substrate with scraper based upon wet process coating followed by heating and curing. Enamel powder was then uniformly distributed on these precoated cold-rolled steel sheets by electrostatic spraying and sintered in a muffle furnace to obtain enameled steel sheets. Adherence and surface porosity of enameled steel sheets were analyzed by drop hammer testing and in surface development method. Compared with uncoated cold-rolled steel sheet for enameling use, all selected preeoatings could improve the adherence properties of enamel layers to some extent, but difference in pyrolysis rate of different resins espe- cially the residue at over 650 R2 would directly affect enamel surface porosity. Tests showed that optimum preeoating could improve enamel adherence level of cold-rolled steel from level 5 （uncoated） to level 1 and control the surface porosity of the thin enamel layer within 200 counts/m2, The adherence of cold-rolled steel sheet for enameling use can be effectively improved by applying polymer precoatings on the steel surface. Selecting precoatings of excellent overall properties and suitable thickness of enamel layer can alleviate or avoid surface porosity defect caused by precoating pyrolysis.