摘要
目的研究液相等离子电解硼碳氮三元共渗处理(PEB/C/N)对Q235低碳钢摩擦电化学行为的影响。方法采用PEB/C/N方法在Q235低碳钢表面制备共渗层,通过电化学的开路电位测试和摩擦磨损实验评估Q235钢基体和PEB/C/N试样在NaCl(质量分数3.5%)腐蚀介质中与Si_(3)N_(4)球对磨的摩擦电化学行为。结果在电压为280 V的PEB/C/N共渗中,试样周围等离子体区的电子温度稳定在3500 K左右。经过PEB/C/N处理30 min后,生成的共渗层包括15μm主要由Fe_(2)B相组成的表面渗层和40μm的过渡层。在摩擦过程中,PEB/C/N试样的开路电位保持在-200~-300 m V之间,且波动较小,明显高于Q235钢基体。同时,PEB/C/N试样的磨损率为3.88×10^(4)μm^(3)/(N·m),只是钢基体磨损率的1/3。在NaCl腐蚀介质中,由于腐蚀和磨损的交互作用,使Q235钢基体产生了塑性应变位错和局部的微裂纹,因此磨损进一步增加,磨损机制主要为疲劳磨损和磨粒磨损。PEB/C/N试样的共渗层有效阻挡了Cl(-)对基体的腐蚀,磨损机制主要为磨粒磨损。结论PEB/C/N试样在NaCl腐蚀介质中的耐腐蚀和耐磨性能得到明显提升。
Plasma electrolytic boriding(PEB)technology is an effective way to form iron borides on the steel surface.Compared with the single boriding process,the multi-element boriding process can further effectively reduce the hardness gradient by forming a transition layer containing C and N elements between the boride layer and the steel substrate,which plays a significant role in improving the performance of the diffusion layer.At present,the evaluation of the corrosion resistance of the boride layer on metal surface is mostly carried out under static corrosion conditions.However,the metal workpiece is more vulnerable due to corrosion and friction interaction in corrosive medium and long-term mechanical operation environment,so studying the tribo-electrochemical behavior of metal in corrosive medium environment is critical.In this work,the plasma electrolytic borocarbonitriding process(PEB/C/N)was carried out in an aqueous solution containing 25wt.%borax,10wt.%glycerin and 3wt.%carbamide.The anode and cathode were set to be the stainless steel bath and the Q235 low-carbon steel sample,respectively.The constant negative bias voltage was increased to 280 V,and the whole processing time was 30 min.The morphology,composition distribution and phase composition of the borocarbonitriding layer were studied.The tribo-electrochemical behavior of Q235 steel substrate and PEB/C/N sample against Si_(3)N_(4) ball in 3.5wt.%NaCl solution was evaluated by electrochemical open-circuit potential(OCP)tests and tribological tests.The results showed that the electron temperature in the plasma zone around the sample was stable at 3500 K in the PEB/C/N process at 280 V.After the PEB/C/N treatment for 30 min,the borocarbonitriding layer contained a 15μm surface layer which was mainly composed of Fe_(2)B phase and a 40μm transition layer.In friction,the open-circuit potential of PEB/C/N sample remained between−200 mV and−300 mV with a small fluctuation,which was obviously higher than the Q235 steel substrate.The corrosion resistance of the PEB/C/N sample was significantly improved.Meanwhile,the wear rate of the PEB/C/N sample was 3.88×10^(4)μm^(3)/(N×m),which was only 1/3 of the Q235 steel substrate,and the wear resistance of the PEB/C/N sample was obviously improved.In the NaCl solution,dislocation increment and migration in plastic deformation occurred on bare Q235 steel due to the interaction of corrosion and wear.There were intensive parallel furrows and obvious fatigue spalling on the wear surface of the Q235 steel substrate,so the wear mechanism of Q235 steel substrate was mainly fatigue and abrasive wear.However,the borocarbonitriding layer of the PEB/C/N sample effectively prevented the corrosion of Cl^(-)on the Q235 substrate.Therefore,the surface damage of the PEB/C/N sample was mainly caused by friction and wear factors in tribo-electrochemical experiments.When the local area of the surface boride layer was destroyed by the Si_(3)N_(4) friction pair,some abrasive particles with high hardness were ground off,and the wear surface of the PEB/C/N sample presented sharp and narrow furrows,so the wear mechanism of the PEB/C/N sample was mainly abrasive wear.
作者
王彬
周茜
高川力
李惠
金小越
薛文斌
WANG Bin;ZHOU Qian;GAO Chuan-li;LI Hui;JIN Xiao-yue;XUE Wen-bin(Department of Basic Science,Shanxi Agricultural University,Shanxi Taigu 030801,China;Key Laboratory of Beam Technology and Materials Modification of Ministry of Education,College of Nuclear Science and Technology,Beijing Normal University,Beijing 100875,China;Institute of Radiation Technology,Beijing Academy of Science and Technology,Beijing 100875,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2023年第6期80-87,共8页
Surface Technology
基金
山西省高等学校科技创新项目(2019L0389)
国家自然科学基金(51671032,51071031)。
关键词
低碳钢
等离子体电解
硼碳氮共渗
开路电位
耐腐蚀性
耐磨性
low-carbon steel
plasma electrolysis
borocarbonitriding
open-circuit potential
corrosion resistance
wear resistance
