钢铁表面常温超声磷化研究

目的通过在钢铁件表面磷化处理中引入超声波,提高磷化膜的外观及耐蚀性。方法首先采用正交实验确定了磷化液的最优配方,其次采用单因素实验考察了超声波作用下磷化p H值、磷化温度、磷化时间、超声功率对磷化膜性能的影响,最后采用扫描电子显微镜和X射线衍射仪,对超声磷化膜和普通磷化膜的微观形貌和物相组成进行了分析。结果正交实验得到的最优磷化液配方为:氧化锌15 g/L,磷酸90 g/L,硫酸羟胺(HAS)10 g/L,硝酸锰4 g/L。各因素对磷化影响主次顺序为:磷酸>硝酸锰>氧化锌>HAS。最佳磷化工艺条件为:磷化液pH值2.3~2.6,磷化温度30℃,磷化时间45 min,磷化超声功率210 W。最优配方及最佳磷化工艺条件下制得的磷化膜结构均匀致密,硫酸铜点滴时间为320 s。超声磷化膜和普通磷化膜相比,前者晶粒长径比接近1,后者晶粒的长径比接近4,前者晶粒分布均匀致密,后者表面颗粒分布不均匀,晶粒间存在较多孔隙。前者物相组成主要是Zn3(PO4)2·4H2O和MnHPO4·3H2O,后者物相组成比前者多了组分Zn2Fe(PO4)2·4H2O。结论超声磷化比普通磷化得到的磷化膜,外观及耐蚀性更优越。

Ultrasound Phosphating of Steel Surface at Room Temperature

The work aims to improve the appearance and corrosion resistance of phosphating film by introducing ultrasound into the phosphating treatment of iron and steel parts.Firstly,the optimum formula of phosphating solution was determined by orthogonal experiment.Secondly,the effects of phosphating p H,phosphating temperature,phosphating time and ultrasonic power on the properties of phosphating film were investigated by single factor experiment.Finally,the morphology and phase composition of phosphating films prepared by ultrasonic phosphating and conventional phosphating were analyzed by scanning electron microscopy and X-ray diffraction.The optimum formula of phosphating solution obtained by orthogonal experiment included zinc oxide of 15 g/L,phosphoric acid of 90 g/L,hydroxylamine sulfate(HAS)of 10 g/L and manganese nitrate of 4 g/L.The order of influence of each factor on phosphating was phosphoric acid>manganese nitrate>zinc oxide>HAS.The optimum phosphating conditions were:p H value of phosphating solution of 2.3~2.6,phosphating temperature of 30℃,phosphating time of 45 min and phosphating ultrasonic power of 210 W.Under the optimum formulation and process conditions,the phosphating film had uniform and compact structure,and the dropping time of copper sulfate was 320 s.Compared with ordinary phosphating film,ultrasound phosphating film had a particle-to-particle ratio close to 1,while the ordinary phosphating film had a particle-to-particle ratio close to 4.The former had uniform and compact particle distribution,while the latter had uneven particle distribution on the surface of the film layer,with more pores among the particles.Phase composition of the former is mainly Zn3(PO4)2·4H2O and MnHPO4·3H2O.For the latter,the component Zn2Fe(PO4)2·4H2O was added to the phase composition.Ultrasound phosphating film has better appearance and corrosion resistance than the ordinary phosphating film.