表面粗糙度对304不锈钢空蚀腐蚀联合作用的影响

Effect of Surface Roughness on Joint Action of Cavitation Corrosion of 304 Stainless Steel

为探究不同表面粗糙度对腐蚀空蚀破坏的影响机制,利用超声空蚀实验装置,对不同表面粗糙度的304不锈钢试样在质量分数35%NaCl溶液中进行空蚀腐蚀联合作用实验。通过分析试样的质量损失、表面形貌、显微硬度和电化学性能变化,探究不同表面粗糙度对空蚀腐蚀表面形貌和性能的影响规律。结果表明:空蚀腐蚀后的304不锈钢试样表面出现蚀坑,且蚀坑主要发生在磨痕边缘,并呈现腐蚀和空蚀双重特征;随着表面粗糙度的增大,蚀坑的密度增加,试样质量损失更加严重,但粗糙度达到一定程度时,空蚀会降低表面粗糙度数值,起到平整作用;经过空蚀腐蚀作用后,试样表面均出现硬化现象,但随着表面粗糙度的增大,试样表面硬化现象变弱;空蚀腐蚀后,试样的腐蚀电流增大,腐蚀电位负移,且随着粗糙度增大,试样的腐蚀电位和腐蚀电流变化也增大,呈现耐腐蚀性能不断下降趋势。

In order to study the influence mechanism of surface roughness on cavitation corrosion,the cavitation corro-sion experiments of 304 stainless steel samples with different surface roughness in 35%NaCl solution were conducted on ultrasonic vibration cavitation experiment device.By analyzing the mass loss,surface morphology,microhardness,and elec-trochemical performance changes of the samples,the influence of different surface roughness on the surface morphology and performance of cavitation corrosion was explored.The results show that cavitation pits occur on the sample surface after cav-itation,and the pits mainly occur at the edge of the wear marks,exhibiting dual characteristics of corrosion and cavitation.With the increase of surface roughness,the density of cavitation pits increases and the mass loss of the samples becomes more serious.However,when the roughness reaches a certain value,cavitation erosion will reduce the surface roughness val-ue and play a flat role.After cavitation corrosion,the sample surface shows a hardening phenomenon.But as the surface roughness increases,the surface hardening phenomenon of the sample weakens.After cavitation corrosion,the corrosion cur-rent of the sample increases,the corrosion potential shifts negatively.As the surface roughness increases,the change of cor-rosion potential and corrosion current of the samples increases,showing a continuous declining trend of corrosion resistance.