Studying the Effect of Micro and Nano Particles Containing Silicon on Strength and Compaction of Monolithic Ramming Al 2 O 3 -SiO 2 -SiC-C Resin Bonded Refractorie s Ebrahim Karamian Oxidation of carbon in monolithic aluminosilicate carbon (Al 2 O 3 -SiO 2 -SiC-C) refractories at high temperatures is a problem causing porosity and strength decrease. Using silicon and related compounds not only acts as antioxidants but also develops SiC bonds producing strength and oxidations resistance at high temperatures. In this study, the effect of micro and nano silicon containing particles on strength and compaction of monolithic resin bond ramming Al 2 O 3 -SiO 2 -SiC-C refractories is considered. Iranian chamotte (0-1 mm) or Chinese bauxite (0-3mm), saggar (0-1mm), coke(0-0.15mm) and phenolic resole (binder) in amounts of respectively 65%, 15% , 10% , 10% and in addition silico and ferrosilicon metals(0-0.1mm) are used. Raw material mixtures are plasticized with phenolic resole, compressed at 4 Mpa and fired first at 200 ?C and then at 1100 ?C and 1400 ?C (2 h). Cold crushing strength (CCS), bulk density (BD) and apparent porosity (AP) are measured according to ASTM and electron microscopy (SEM and TEM), semi quantitative analysis (EDX), phase analysis (XRD) and infrared spectroscopy (FTIR) are performed on selective samples. Results show that up to 6% ferrosilicon and 5% silicon produces nano silicon carbide whiskers (?-SiC) with 50-100 nm diameters and uniform network increasing the mechanical strength 3-4 times. XRD, FTIR and EDX showed SiC phase in nano whiskers. The morphology of these whiskers and TEM studies on tip of them indicated Fe as catalyst and VLS mechanism of formation. Thermal analysis (STA) approved SiO gas formation on liquid droplets. Electron diffraction (SAED) in TEM showed bright spots and parallel narrow lines, indicating respectively crystalline and some defects of whiskers. Quantitative XRD phase analysis by Ratio of Slopes Method indicated 50% SiC is developed between Si and C at 1500 ?C (2 h). Keywords: Aluminosilicate, Carbon, Ramming, Monolithic Refractoris, Resole, Silicon compounds, Strength, Compaction, Whisker formation, Silicon carbide
