CAJ | 학술논문

采用复合镀渗工艺,对316L不锈钢表面刷镀的两种纳米陶瓷颗粒(非晶纳米SiO_2(n-SiO_2)和纳米SiC(n-SiC)颗粒)增强的复合镀层进行双辉Ni-Cr-Mo-Cu多元共渗处理,成功地在316L不锈钢表面制备了纳米颗粒增强Ni基合金层.利用XRD、SEM和TEM对两种复合镀渗层的微观组织进行观察,采用极化曲线、电化学阻抗谱(EIS)和冲刷腐蚀试验对两种复合镀渗层的耐蚀性和耐冲蚀性能进行研究.对两种颗粒增强的复合镀渗层的微观组织分析结果表明:在双辉多元共渗工艺(1000 ℃)条件下,电刷镀含n-SiO_2颗粒的复合镀渗层中的SiO_2颗粒仍保持非晶态;而电刷镀含n-SiC颗粒的复合镀渗层中的SiC颗粒已完全分解并与基体合金元素发生反应,导致在晶内析出三元硅化物Cr_(6.5)Ni_(2.5)Si和沿晶界析出碳化物Cr_(23)C_6.在3.5%NaCl(质量分数, 下同)溶液中的电化学腐蚀实验结果表明:SiO_2颗粒增强的复合镀渗层存在明显的钝化区,点蚀电位和维钝电流密度与Ni基合金渗层的十分接近,而电刷镀含SiC颗粒增强的复合镀渗层处于活化状态,但其耐蚀性能仍略强于不锈钢;两种复合镀渗层的EIS图谱均呈现单容抗弧特征,与Ni基合金渗层相比,SiO_2颗粒增强的复合镀渗层的容抗弧幅值略微减少,而SiC颗粒增强的复合层的容抗弧幅值明显下降,但仍略高于316L不锈钢.在液/固两相流(10%HCl+10%石英砂)条件下的冲刷腐蚀实验结果表明:SiO_2颗粒增强的复合镀渗层具有最佳的耐冲蚀性能,而316L不锈钢的耐冲蚀性能最差.
채용복합도삼공예,대316L불수강표면쇄도적량충납미도자과립(비정납미SiO_2(n-SiO_2)화납미SiC(n-SiC)과립)증강적복합도층진행쌍휘Ni-Cr-Mo-Cu다원공삼처리,성공지재316L불수강표면제비료납미과립증강Ni기합금층.이용XRD、SEM화TEM대량충복합도삼층적미관조직진행관찰,채용겁화곡선、전화학조항보(EIS)화충쇄부식시험대량충복합도삼층적내식성화내충식성능진행연구.대량충과립증강적복합도삼층적미관조직분석결과표명:재쌍휘다원공삼공예(1000 ℃)조건하,전쇄도함n-SiO_2과립적복합도삼층중적SiO_2과립잉보지비정태;이전쇄도함n-SiC과립적복합도삼층중적SiC과립이완전분해병여기체합금원소발생반응,도치재정내석출삼원규화물Cr_(6.5)Ni_(2.5)Si화연정계석출탄화물Cr_(23)C_6.재3.5%NaCl(질량분수, 하동)용액중적전화학부식실험결과표명:SiO_2과립증강적복합도삼층존재명현적둔화구,점식전위화유둔전류밀도여Ni기합금삼층적십분접근,이전쇄도함SiC과립증강적복합도삼층처우활화상태,단기내식성능잉략강우불수강;량충복합도삼층적EIS도보균정현단용항호특정,여Ni기합금삼층상비,SiO_2과립증강적복합도삼층적용항호폭치략미감소,이SiC과립증강적복합층적용항호폭치명현하강,단잉략고우316L불수강.재액/고량상류(10%HCl+10%석영사)조건하적충쇄부식실험결과표명:SiO_2과립증강적복합도삼층구유최가적내충식성능,이316L불수강적내충식성능최차.
Two kinds of nanoparticles reinforced with Ni-based composite alloying layer were prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO_2 and nano-SiC were firstly predeposited by brush plating. The microstructure of the two kinds of nanoparticles was investigated by XRD, SEM and TEM. Their corrosion resistance and erosion-corrosion resistance were analyzed by Tafel Plot, electrochemical impedance spectroscopy (EIS) and erosion-corrosion tests. The results indicate that under the alloying temperature (1000 oC) condition, the amorphous nano-SiO_2 particles still kept the amorphous structure, whereas the nano-SiC particles was decomposed and Ni and Cr reacted with SiC to form Cr_(6.5)Ni_(2.5)Si and Cr_(23)C_6. The corrosion test results indicate that the alloying layer reinforced by amorphous nano-SiO_2 particles display passivation, and the pitting potential (Epit) and passive current (ip) are slightly smaller than that of single alloying layer, whereas the Ni-based alloying layer reinforced by nano-SiC particles is active in 3.5% NaCl solution (mass fraction, similarly hereinafter). The results of impedance spectroscopy of measured samples show that the Nyquist plots of Ni-based alloying layers consisted of single capacitance arc. Compared with the single alloying layer, the capacitance arc of the amorphous nano-SiO_2 particles reinforced by Ni-based composite alloying layer is slightly decreased. The capacitance arc of alloying layer reinforced by nano-SiC particle is lower than that of the single alloying layer and nano-SiO_2 particles reinforced by Ni-based composite alloying layer, but still higher than that of 316L substrate. The erosion-corrosion results indicate that the alloying layer reinforced by amorphous nano-SiO_2 particles show the highest erosive-corrosive resistance of the three alloying layers, while the 316L stainless steel is the worst.