Investigation into the kinetic behavior of molten aluminum pressureless infiltration into SiC preforms

Abstract

Infiltration of molten metal into ceramic performs without using external force is a new fabrication method for metal-matrix composites. In this research, the kinetics of pressureless infiltration in the processing of Al/SiC composites have been investigated. In order to improve the wettability and infiltration properties, Al-6Mg (wt.%) alloy was prepared. Also, the ceramic component was coated for 15 min using electroless copper plating at a temperature of 60 – 70 °C ( pH = 12.5) and a rate of 17 – 20 μm s ⁻¹. Infiltration of molten aluminum into the coated ceramic perform was successfully carried out in the temperature range of 850 to 950 °C under nitrogen atmosphere. Microstructural investigations indicated a well-bonded metal–ceramic joint. Kinetic studies showed that the melt infiltration into the ceramic foam follows an S-shaped curve. The infiltration rate was specified with respect to variables such as the experiment temperature and the size of the pores of the ceramic component. The results revealed that by increasing the temperature and the size of pores, the infiltration rate increases. For infiltrating molten metal into the 10 and 30 ppi foams, activation energies of 5.902 kJ mol ⁻¹ and 7.232 kJ mol ⁻¹ are required, respectively.