| The Fe-Si3N4 materials were synthesized using Fe-Si alloy as major starting material in N2 atmosphere below 1400H ℃ .The heating pattern and nitriding rate of the synthesis of Fe-Si3N4 were researched. In addition, the effect of Fe-Si3N4 powder on bulk density, linear change rate, slag resistance, oxidation resistance and mechanical property of Al2O3 -SiC-C castables and ramming mixes were also studied.The nitriding curves of Fe-Si3N4 specimens were tested by TG and DTA in N2 atmosphere. The heating pattern of synthesizing Fe-Si3N4 using FexSi as starting material in nitriding furnace was drawn up as follows: room temperature800 ℃ ,10 ℃ /min;8001200℃ ,5 ℃/min; 1200 ℃ ,holding for 30 min; 1200-1400 ℃ ,3 ℃/min;1400 ℃,holding for 180 min; then cool below 400 ℃ naturally and open the furnace and take out the specimens. The total heating-up and holding time is 7 hours and 15 minutes. The weight gain analysis results are almost same as the XRD results, revealing that the nitriding rate reaches more than 90%. The particle size of Fe-Si3N4 powder is in the range of 0-0.074 mm.The Fe-Si3N4 powder has some effects on the properties of Al2O3 —SiC-C castables and ramming mixes. For the Al2O3 -SiC-C castables, its bulk density increases and linear change rate decreases with the increase of Fe-Si3N4 addition; however, for the ramming mix, its bulk density decreases and linear change rate increases with the increase of Fe-Si3N4 addition due to the effect of technological factors;For both of them, their crushing strength and modulus of rupture increase after adding Fe-Si3N4 and their slag resistance shows the best when the addition of Fe-Si3N4 is 9%.By comparing the properties of Al2O3 -SiC-C castables and ramming mixes, XRD and SEM microstructure analysis results, the optimum addition of Fe-Si3N4 is decided to be 10%.
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