Agus Sukarto Wismogroho

Iron aluminide coating on Al by mechanical alloying

Abstract The formation of iron aluminide coating on an Al surface by mechanical alloying with Al–Fe powder of various compositions was investigated. When the amount of Fe powder in the starting powder is >50 at.‐%, an FeAl containing coating layer is formed. As the mass ratio of the balls and substrate to the powder in the pot is small, the formation of FeAl phase is achieved in a short time. The obtained FeAl containing coating layer has high hardness and fracture toughness. When the amount of Fe powder in starting powder is <50 at.‐%, a coating layer consisting of FeAl and Fe2Al5 is formed. The coexistence of Fe2Al5 in the coating layer causes the coating layer to be more brittle.

Fe-Si-Al Alloys Prepared by a Spark Plasma Sintering Technique

Fe-Si alloys with various concentration of Al (0, 1, 3 and 5 % by mass) were synthesized by a spark plasma sintering technique. The specimens were prepared in an evacuated chamber of less than 4 Pa and under compressive stress of 40 MPa. During spark discharge, the heating rate was fixed at 10°C/min. After the SPS process was completed, the specimen surfaces were ground with silicon carbide papers. The metallographic characterization was performed by mean of X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive X-ray (EDX) spectroscopy. According to sintering curves, all samples seem to have a similar sintering behavior. The densification of specimens was completed in the temperature range of about 1020-1050°C. Microstructure and phase characterization revealed that the alloys were mainly composed of FeSi2 and FeSi phases containing oxide inclusions. The SEM images indicated that the fraction of FeSi phase and oxide inclusions appears to decrease with increase in Al concentration in the Fe-Si alloy.

In Situ Al/Al2O3 Composite Coating on Steel Substrate Prepared by Mechanical Alloying at High Temperature

In this study a new technique for producing an Al/Al2O3 composite coating on a steel substrate by an in situ process was examined. The pre-treating of the steel substrate with Al was carried out by MA at room temperature, followed by MA using a low-energy ball mill at 200-500°C. An Al/Al2O3 coating layer with a homogenous distribution of Al2O3 particles were achieved. The coating layer has not only high hardness but also high fracture toughness.