Preparation of Al2O3 Nano-Particles Reinforced Fe-Based Composite Materials via In Situ Synthesis
Al2O3 reinforced iron based composite were prepared via in-situ synthesis with aluminum nitrate, citric acid and iron powder as raw materials, a little C and Mo as additive. The influences of the contents of Al2O3, C and Mo on the microstructure and micro-hardness of the Fe based composites were characterized by XRD, SEM, TEM and micro-hardness tester. The results showed that the Fe-based composite materials with high bonding strength between matrix and Al2O3 can be prepared by in situ synthesis method. The best ratio of the nine Al2O3 particles reinforced Fe-based composite materials in three groups is 3vol. % C, 5vol. % or 7vol. % Al2O3, sintering temperature is 1300°C and quenching temperature is 900°C. The microstructure of the matrix without C addition is ferrite before and after quenching; the microstructure of the matrix with C addition is pearlite before quenching, and the microstructure become to martensite after quenching, the α-Al2O3 and FeC3 are reinforced phases. The microstructure of the matrix with Mo addition is ferrite and FeAl2O4 before and after quenching.