工艺参数对38MnVS钢锰系磷化膜表面形貌和耐蚀性的影响

目的研究磷化温度和时间对38MnVS钢磷化膜表面形貌、膜厚和耐蚀性的影响,获得38MnVS钢锰系磷化的最佳工艺参数。方法通过控制单因素变量,在不同磷化温度和时间下在38MnVS表面制备锰系磷化膜。通过扫描电镜(SEM)、测厚仪和硫酸铜点蚀测试等方法,对38MnVS钢表面磷化膜形貌、膜厚及耐蚀性能进行了分析。结果 38MnVS钢表面磷化膜为非均匀形核,磷化膜晶粒首先形成于划痕和晶界处。随磷化时间延长,磷化膜晶粒迅速覆盖基体表面,磷化膜厚度和耐蚀性不断增加。当磷化时间大于15 min时,磷化膜性能变化不大。当磷化温度小于75℃时,不利于磷化膜的生长,磷化膜不能完全覆盖基体,磷化膜的厚度和耐蚀性较低。随磷化温度的升高,磷化膜晶粒不断长大,磷化膜厚度和耐蚀性迅速增加。当磷化温度超过95℃时,磷化膜性能增速下降。结论 38MnVS钢的最佳磷化工艺为:85℃,15 min。

Effects of Process Parameters on Morphology and Corrosion Resistance of Manganese Phosphating Film on 38MnVS Steel

The work aims to obtain optimum process parameters of manganese phosphating film on 38MnVS steel by studying influence of phosphating temperature and time on morphology,film thickness and corrosion resistance of 38MnVS steel.Manganese phosphating film was prepared on the surface of 38MnVS provided with different phosphating temperature and time by controlling single-factor variables.Morphology,film thickness and corrosion resistance of 38MnVS steel phosphating film were analyzed using scanning electron microscope (SEM),thickness gauge and performing bronze sulfate pitting test.The phosphating film was heterogeneous nucleation and first formed on scratches and grain boundaries.As phosphating time prolonged,grains of the phosphating film covered the substrate surface quickly,and both film thickness and corrosion resistance increased continuously.Performance of the phosphating film changed slightly when phosphating time exceeded 15 min.At the phosphating temperature of below 75 ℃,growth of the film was inhibited,the film failed to cover the substrate,and the film thickness and corrosion resistance were low.As the phosphating temperature rose,the grains grew continuously,thickness and corrosion resistance increased rapidly.At the phosphating temperature of over 95 ℃,performance of the film increased slowly.The optimum phosphating process of 38MnVS steel is 85 ℃ and 15 min.