| FANG Hui-min,ZHANG Guang-sheng,XIA Lian-sen.Properties and Growth Kinetics of Boronized Layer of Boride Strengthened Fe-based Powder Metallurgy Material[J],49(7):338-345 |
| Properties and Growth Kinetics of Boronized Layer of Boride Strengthened Fe-based Powder Metallurgy Material |
| Received:November 04, 2019 Revised:July 20, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.07.042 |
| KeyWord:Fe-based materials powder boronizing diffusion coefficient diffusion activation energy microhardness Rockwell-C adhesion test |
| Author | Institution |
| FANG Hui-min |
1.School of Mechanical Engineering, Anhui Technical College of Mechanical and Electrical Engineering, Wuhu , China; 2.School of Mechanical & Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing , China |
| ZHANG Guang-sheng |
3.School of Materials, Anhui Polytechnic University, Wuhu , China |
| XIA Lian-sen |
3.School of Materials, Anhui Polytechnic University, Wuhu , China |
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| Abstract: |
| The work aims to prepare a specimen with a boronized layer by directly sintering Fe-based powder metallurgy material with solid powder boronizing method. Solid boronizing technology was used to treat the Fe-based powder metallurgy material at temperature of 1123, 1223, and 1323 K for 3, 5, 7 and 10 h. The morphology of the boronized layer was observed with an optical microscope and a scanning electron microscope (SEM), and the thickness of the boronized layer was measured. The phase composition of the boronized layer was analyzed by X-ray diffractometer. The wear resistance of boronized layer was evaluated by the friction and wear test. The quality of the bonding strength between the boronized layer and the substrate was evaluated by the Rockwell-C adhesion test. The growth kinetics curve of the boronized layer was fitted to obtain the plot of the boronized layer kinetics curve and thickness. The thickness of the boronized layer of the specimen was 35~183 μm. A bi-phase boronized layer (Fe2B+FeB) was obtained under 1323 K, and a single-phase boronized layer Fe2B was obtained under conditions of 1123 K and 1223 K. The specimen obtained the best wear resistance at 1223 K for 5 h and the quality of the bonding strength of boronized layer was approved by the HF3 grade according to the specifications. The diffusion activation energy of B atoms in this experiment was 164 kJ/mol. The sintering temperature and boronizing time are closely related to the thickness of the boronized layer, and the relationship between the boronizing time and the thickness of the boronized layer is in a parabolic form. The square of the thickness value and the boronizing time accord with the Arrhenius formula and have a linear relationship. The microhardness of the boronized layer is significantly higher than that of the substrate. With the increase of time, more holes and looseness appear in the layer, and the shape of the boronized layer gradually changes from an obvious comb-tooth shape to a less obvious comb-tooth shape, which is more obvious at high temperature. |
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