MICROSTRUCTURE AND OXIDATION RESISTANCE OF Fe-Al-Nb ALLOYED LAYER ON 45 STEEL BY PLASMA SURFACE MODIFICATION

Affiliation of Author(s):材料科学与技术学院

Journal:SURFACE REVIEW AND LETTERS

Key Words:Fe-Al coating Fe-Al-Nb alloyed layer high-temperature oxidation plasma surface modification

Abstract:The Fe-Al-Nb alloyed layer was coated on 45 steel by the plasma niobiumizing modification to improve the microstructure and oxidation resistance of Fe-Al coating prepared by hot-dipping aluminum. The alloyed layer growth followed the typical Volmer-Weber mode with the modification time growing (2-4 h), which was carried out at 1073K and pressure of 40 Pa. Its surface morphology was compact without any defects, meanwhile, there was a transition layer between the Fe-Al-Nb alloyed layer and the substrate. The mass increase of Fe-Al-Nb specimen after oxidizing at 873, 973 and 1073K for 100 h was less than that of the Fe-Al and untreated 45 steel specimen, it owed to the diffusing fully of the Fe, Al and Nb atoms during high-temperature oxidation, forming a compact protective Nb, Al-rich oxidation film on the surface of the Fe-Al-Nb alloyed layer, and the occurrence of the internal oxidation phenomenon between the loose iron oxides layer and the Fe-Al-Nb alloyed layer at 973K for 100 h protected the internal coating from further penetration of oxygen. In addition, the Fe2Nb precipitates and Nb carbides dispersed through the alloyed layer, which were good for improving the strength, creep rupture resistance and inhibiting the Kendal effect at high-temperature.

ISSN No.:0218-625X

Translation or Not:no

Date of Publication:2017-04-01

Co-author:Zhang, Zelei

Correspondence Author:Yao Zhengjun

Date of Publication:2017-04-01