AISI 316奥氏体不锈钢等离子体源渗氮及其耐磨抗蚀性能

目前,对AISI 316奥氏体不锈钢单一面心结构γΝ相改性层耐磨抗蚀性能的报道差异较大,有些甚至相互矛盾。采用等离子体源渗氮技术,于450℃,6 h改性AISI 316奥氏体不锈钢,获得了厚度约为17μm、峰值氮浓度20%(原子分数)、最大显微硬度1 510 HV0.1 N、单一面心结构的γΝ相改性层。分别采用WTM-2E球盘式磨损仪和PARSTAT2273电化学工作站,研究了干摩擦条件下γN相/Si_3N_4陶瓷球的摩擦磨损行为和在3.5%NaCl溶液中的电化学腐蚀行为,揭示了γN相改性层的耐磨抗蚀机理。结果表明:γΝ相改性层的磨损机制由原不锈钢的黏着磨损转变为氧化磨损,摩擦系数由0.88降低至0.65,磨损体积由0.13 mm~3降低到9.50×10-3mm~3,耐磨性能显著提高;γΝ相改性层阳极极化曲线未发生点蚀击穿过程,容抗弧直径增大,相位角平台变宽;采用等效电路Rs-(Rct//CPE)拟合的电荷转移电阻Rct由原不锈钢的1.006×105Ω·cm~2增至1.377×106Ω·cm~2,计算的双电层电容Cdl由88.4m F/cm~2降低至77.8 m F/cm~2,抗蚀性能明显得到了改善。

Wear and Corrosion Resistance of AISI 316 Austenitic Stainless Steel After Plasma Source Nitriding Treatment

AISI 316 austenittc stainless steel was modified by plasma source nitriding technique under 450 ℃ for 6 h,and the single facecentered-cubic phase (γN) modified layer with thickness of 17 μm,20％ (atom fraction) peak value of N content and maximum microhardness of 1 510 HV0.1 N was obtained.WTM-2E ball-disc abrading instrument and PARSTAT2273 electrochemical workstation were utilized respectively to study the tribological behavior of γN phase/Si3N4 ceramic counterface under dry friction condition and the electrochemical corrosion behavior in 3.5％ NaC1 solution,which could further reveal wear and corrosion mechanism of γN phase.Results showed that the wear mechanism of γN phase modified layer changed from adhesion wear of original stainless steel to oxidation wear,and the friction factor decreased from 0.88 to 0.65,as well as the wear volume reduced from 0.13 mm3 to 9.50× 10-3 mm3,which indicated that the wear resistance was improved greatly.Furthermore,the pitting corrosion process of the γN phase modified layer was not observed from the anodic polarization curve,and the EIS of the γN phase passive film possessed a larger diameter of capacitive arc and wider phase degree range.Calculated based onequivalent circuit Rs-(Rct//CPE),the fitting charge transfer resistance Rct increased from 1.006× 105 Ω · cm2 of original stainless steel to 1.377×106 Ω · cm2,and the calculated double layer capacitance Cdl decreased from 88.4 mF/cm2 to 77.8 mF/cm2,which demonstrated that the corrosion resistance was enhanced.