中性盐雾腐蚀对等离子喷涂NiCr-Cr3C2涂层摩擦磨损性能的影响

Effect of Neutral Salt Spray Corrosion on Tribological Properties of SPSed NiCr-Cr_3C_2 Coatings

利用超音速等离子喷涂(SPS)技术制备了陶瓷相增强的NiCr-Cr_3C_2涂层,采用线接触往复滑动方式进行摩擦磨损实验,测定了NiCr-Cr_3C_2涂层/Q235碳钢摩擦副在盐雾腐蚀前后涂层的摩擦系数和磨损量,此外,还采用SEM、EDS等技术观察分析了涂层表面的形貌和微区元素分布,探讨了盐雾腐蚀环境对涂层摩擦磨损性能的影响。结果表明:NiCr-Cr_3C_2涂层的磨损机制主要为磨粒磨损和氧化磨损,而盐雾腐蚀后的磨损机制为粘着磨损、磨粒磨损和腐蚀磨损。盐雾腐蚀后涂层的摩擦系数比盐雾腐蚀前的摩擦系数降低了1/5;不过,盐雾腐蚀后涂层的磨损失重量是盐雾腐蚀前磨损失重量的5倍左右,说明盐雾腐蚀环境加速了其摩擦学性能的恶化,涂层的耐蚀性有待进一步提高。

Ceramic phase strengthened NiCr-Cr3C2 coatings were prepared by HEPJet supersonic plasma spaying （SPS）. The friction coefficients and wear loss for NiCr-Cr3C2 coating and Q235 steel pairs under dry and salt spray corrosion for one week were measured using the UMT-3 friction and wear tester by line-contact reciprocating sliding. The morphology and element distribution of worn surfaces were analyzed by SEM and EDS, respectively. The effects of salt spray corrosion environment on tribological properties of the coatings were discussed. The result shows that the wear mechanism of NiCr-Cr3C2 coatings is abrasive and oxidative wear, whereas under salt spray corrosion conditions, it becomes adhesive, abrasive and corrosion wear. The friction coefficient under salt spray corrosion conditions is significantly reduced by 1/5, but the wear losses under salt spray corrosion conditions are about 5 times more than that under dry friction conditions, which demonstrates that the salt spray corrosion environment accelerates the deterioration of coating＇s tribological properties and the corrosion resistance of the coating remains to be further improved.