Corrosion behavior of Fe amorphous/Al-12Si piston composites with core-shell structure
Yingdong Wang1, Zuxiang Lin1, Chengzhou Liu1
1College of Mechanical and Transportation Engineering, Southwest Forestry University, Kunming, 650224, China.
Scientific Reports
|January 22, 2025
Summary
Adding iron (Fe) amorphous particles to aluminum-silicon (Al-12Si) enhances corrosion resistance in biodiesel engine components. Optimal doping (2-10%) improves passivation and reduces corrosion, with 10% Fe showing the best results.
Area of Science:
- Materials Science
- Corrosion Engineering
- Tribology
Background:
- The current Al-12Si piston material is susceptible to corrosion in biodiesel engine lubrication systems due to insufficient passivation, especially in the presence of chloride ions (Cl-).
- Iron (Fe) amorphous particles offer potential as a reinforcing agent due to their excellent corrosion resistance, passivation ability, and high-temperature stability, showing good compatibility with Al-12Si.
Purpose of the Study:
- To synthesize and characterize Fe amorphous/Al-12Si core-shell structural composites (FACS) for improved piston material performance.
- To investigate the electrochemical corrosion behavior and mechanism of FACS in simulated biodiesel engine environments.
- To determine the optimal doping concentration of Fe amorphous particles for enhanced corrosion resistance.
Main Methods:
- Synthesis of FACS via ball milling and hot extrusion.
- Characterization using X-ray diffraction, optical microscopy, and EDS spectroscopy.
- Electrochemical corrosion evaluation through potentiodynamic polarization and electrochemical impedance spectroscopy.
Main Results:
- Fe amorphous particles retained their amorphous structure and passivation ability after processing at 440°C.
- Optimal doping (2-10% Fe) resulted in FACS with uniform composition, high density, low porosity, and improved corrosion resistance (reduced icorr, increased Ecorr).
- Excessive doping (20% Fe) led to agglomeration, defects, and reduced corrosion resistance.
Conclusions:
- Fe amorphous particles enhance the corrosion resistance of Al-12Si by promoting uniform surface potential and improving passivation.
- FACS with 2-10% Fe amorphous particles demonstrate significantly improved corrosion resistance compared to pure Al-12Si.
- FACS with 10% Fe amorphous particles exhibited the highest corrosion resistance, identifying it as a promising material for biodiesel engine pistons.
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