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研究了45钢氯系盐浴渗铬工艺与固溶渗氮预处理对盐浴渗铬试样耐蚀性的影响。结果表明,采用CaCl2-NaCl-NaF为基盐,以铬粉、铬盐和铬的氧化物为供铬剂,经850℃×6 h盐浴渗铬,可在试样表面获得20~30 mm厚的致密渗铬层。表层硬度1400~1700 HV0.3,渗铬样表层铬浓度为65%~90%。X射线衍射分析表明渗铬表层主要由Cr-Fe固溶体、铬的碳化物和少量氧化物组成。阳极极化曲线的测定分析表明,所有盐浴渗铬试样的耐蚀性普遍优于304不锈钢。其中固溶渗氮+盐浴渗铬复合处理试样的渗层钝化电流为(3.2~5.3)×10-5mA/cm2,远低于不锈钢和单一盐浴渗铬试样。
The effects of 45 steel chlorine-based salt bath chromizing process and solution-nitriding pretreatment on corrosion resistance of salt bath chromizing samples were studied. The results show that CaCl2-NaCl-NaF as base salt, chrome powder, chromium salt and chromium oxide as chromium supply, 850 ℃ × 6 h salt bath chromizing, can be obtained on the sample surface 20 ~ 30 mm Thick and dense chromizing layer. Surface hardness of 1400 ~ 1700 HV0.3, chromium-like surface chromium concentration of 65% to 90%. X-ray diffraction analysis shows that the chromizing surface layer is mainly composed of Cr-Fe solid solution, chromium carbide and a small amount of oxide. Anodic polarization curve analysis showed that all salt bath chromizing samples generally better corrosion resistance 304 stainless steel. The passivation passivation current of solid solution nitriding + salt bath chromizing composite sample was (3.2 ~ 5.3) × 10-5mA / cm2, much lower than stainless steel and single salt bath chromizing samples.