Thermo-mechanical properties of Al2O3-C refractories with in situ synthesized non-oxide bonding phases

Enhanced mechanical properties of lightweight Al2O3‐C refractories reinforced by combined one‐dimensional ceramic phases

“…An illustration of the aggregate-T and aggregate-M to compare their microstructures is given in Figure 1. The microstructures and properties of the aggregate-M were described thoroughly in Chen et al 41,44,45 Specifically, compared with dense corundum aggregates in conventional Al 2 O 3 -C refractories [20][21][22][23][24][25][26] and other microporous corundum aggregates, [47][48] the aggregate-M had a higher apparent porosity of 25.7 % and contained more micropores. The median pore size of the aggregate-M was 4.2 μm.…”

“…[12][13][14][15][16][17] Recent researches demonstrated that the ceramic reinforcement phases of carbon containing refractories play a major role in the enhancement of mechanical properties. [18][19][20][21][22] One of the best-known methods to increase the strength of the matrix of Al 2 O 3 -C refractories is the in situ formation of SiC whiskers by adding metallic Si powder. [23][24][25][26][27] For example, Al 2 O 3 -C refractories containing ultrafine microcrystalline graphite fostered the formation of intertwined SiC whiskers, which caused a significantly higher strength.…”

“…Recent researches demonstrated that the ceramic reinforcement phases of carbon containing refractories play a major role in the enhancement of mechanical properties 18–22 . One of the best‐known methods to increase the strength of the matrix of Al 2 O 3 ‐C refractories is the in situ formation of SiC whiskers by adding metallic Si powder 23–27 .…”

Microstructure, properties, and application of low carbon Al2O3‐C refractories used as submerged entry nozzles

“…When the newly formed Si enters the molten Al, the viscosity of the melt would be decreased, favoring the nucleation and growth of whiskers. 28 Actually, this reaction is feasible in thermodynamics even at 1000°C because the Gibbs free energy change is rather negative according to Yin et al 29 Moreover Bitencourt et al found that aluminum would preferentially react with nitrogen and oxygen when combined with Si particles, decreasing the likelihood of forming aluminum-carbon based compounds. 28 However, the formed Al 4 C 3 is not stable at higher temperatures (≥1100°C) because of high partial pressure of CO based on Reaction 9.…”

“…28 However, the formed Al 4 C 3 is not stable at higher temperatures (≥1100°C) because of high partial pressure of CO based on Reaction 9. 28 Actually, this reaction is feasible in thermodynamics even at 1000°C because the Gibbs free energy change is rather negative according to Yin et al 29 Moreover Bitencourt et al found that aluminum would preferentially react with nitrogen and oxygen when combined with Si particles, decreasing the likelihood of forming aluminum-carbon based compounds. 19 Although nano carbon black has higher reactivity with Al, the higher content of silicon powder in the sample LAC would further prevent the generation of Al 4 C 3 and favor the formation of Al 2 O 3 and SiC.…”