| YU Cheng-tao,CHEN Ming-hui,WANG Fu-hui.Mechanical and Tribological Properties of FHG97/WS2 Self-lubricating Composites[J],52(3):143-150, 227 |
| Mechanical and Tribological Properties of FHG97/WS2 Self-lubricating Composites |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.03.011 |
| KeyWord:nickel-based self-lubricating material high temperature tribological properties lubricity wear mechanisms |
| Author | Institution |
| YU Cheng-tao |
Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang , China;School of Mechanical Engineering, Ningxia Institute of Science and Technology, Ningxia Shizuishan , China |
| CHEN Ming-hui |
Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang , China |
| WANG Fu-hui |
Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang , China |
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| Abstract: |
| In the research of high temperature self-lubricating composites, researchers often focus on the characterization of tribological properties, but pay little attention to the mechanical properties of composites, so it is difficult to evaluate their utility. The work aims to investigate the effects of WS2 addition on the mechanical and tribological properties of nickel-based self-lubricating composites. Three kinds of FGH97/WS2 composites with different WS2 content 0wt% (FW0), 6wt% (FW1) and 12wt% (FW2) were prepared by spark plasma sintering technology. The tribological properties of the composites in the range of 25-600 ℃ were tested by reciprocating friction and wear tester, and the wear rate and scratch profile were measured by white light interferometer. A hardness tester was used to test the hardness of the material at room temperature, and a universal testing machine was used to test the compressive strength and flexural strength of the material at room temperature. The phase of the materials was analyzed by X-ray diffractometer. The morphology and composition of the scratch were observed and analyzed by scanning electron microscope with energy spectrometer. The phase compositions of worn surface were characterized by Raman scattering instrument. The results showed an in-situ solid-state reaction between WS2 and FHG97, generating the CrxSy and M6C phases during the composite sintering. With the increase of WS2 content, the hardness and compressive yield strength of the composites increased. The flexural strength of FW1 was basically the same as that of the matrix FW0, while the flexural strength of FW2 decreased significantly. At 25-600 ℃, the friction coefficients of the three materials decreased with the increase of temperature. The friction coefficient decreased more obviously with the increase of WS2. At 25-200 ℃, due to the poor deformation ability of the material, abrasive wear and adhesive wear mainly occurred, which made FW0 and FW1 have high friction coefficient and high wear rate. At 200 ℃, the FW2 exhibited good tribological properties, with a friction coefficient of 0.36 and a wear rate of 8.6×10-5 mm3/(N.m). At 400 ℃, FW0 and FW1 undergo tribo-induced oxidation, and NiO, Cr2O3 and NiCr2O4 were formed on the wear surface, which improved the tribological properties. FW1 had excellent tribological properties due to the synergistic effect of oxides and CrxSy, with a friction coefficient of 0.33 and a wear rate of 1.9×10–5 mm3/(N.m). At 600 ℃, the surface of FW0 was instantly oxidized to form a continuous smooth enamel layer rich in Cr2O3, which significantly improved the tribological properties of the matrix. However, CrxSy decreased the adhesion of oxide film and increased the wear rate of FW1 slightly. The falling off hard phase M6C caused abrasive wear on FW2 surface, resulting in no oxide film on the surface and exacerbated surface wear. In summary, the prepared FGH97/WS2 composites have excellent mechanical properties, and FW1 has the best tribological properties at 25-600 ℃. The addition of WS2 in FGH97/WS2 system should consider the consumption of Cr in the matrix by in situ reaction, so as to avoid the failure to form a protective oxide film at high temperature. |
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