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运用高能喷丸法(highenergyshotpeening,HESP)在工业纯铁表面获得一定厚度的自纳米化层;在真空炉中通过外加50MPa压力和500℃,12h扩渗条件实现Cr、Ni元素快速向自纳米化层中的扩渗,实现工业纯铁表面不锈钢化(surfacestainless-steel-likealloying,SSA)。运用金相显微镜,扫描电镜,X射线衍射分析以及电化学测试系统等手段对自纳米化层、合金化层的组织结构与耐蚀性等进行表征。结果表明,采用高能喷丸法,在0.6MPa压力下喷丸10min,可在工业纯铁表面获得平均晶粒大小为34.6nm、微观畸变为0.0273%的自纳米化层。由于自纳米化纯铁含有大量晶界,为合金元素扩散提供了通道,在500℃温度下,通过Cr、Ni元素的快速扩渗可在工业纯铁表面获得类似不锈钢成分的合金化改性层。经表面不锈钢化处理的工业纯铁自腐蚀电位达到–0.565V,要高于原始试样及自纳米化处理试样,自纳米化后不锈钢处理使纯铁的耐蚀性有所提高。
Using highenergyshotpeening (HESP), a certain thickness of self-nanocrystallization layer was obtained on the surface of industrial pure iron. Cr and Ni elements were quickly self-nanocrystallized by applying 50MPa pressure and 500 ℃ for 12h in a vacuum furnace Layer of infiltration, to achieve industrial pure iron surface stainless steel (surfacestainless-steel-likealloying, SSA). The microstructure and corrosion resistance of self-nanocrystallization and alloying layers were characterized by means of metallographic microscope, scanning electron microscopy, X-ray diffraction analysis and electrochemical test system. The results show that the shot peening at 0.6MPa for 10min can obtain the self-nanocrystallization layer with the average grain size of 34.6nm and the microscopic distortion of 0.0273% on the surface of industrial pure iron. Since the self-nano-sized pure iron contains a large number of grain boundaries, it provides a channel for the diffusion of the alloying elements. At temperatures of 500 ° C., an alloying modified layer similar to stainless steel can be obtained on the surface of the industrial pure iron by rapid diffusion of Cr and Ni elements . After the stainless steel surface treatment of pure iron corrosion potential reached -0.565V, higher than the original sample and self-nano-processing samples, since the nano-stainless steel after treatment to improve the corrosion resistance of pure iron.