Effect of Sheet Nanocarbon on Properties of Low Carbon Al_2O_3-C Refractories

摘要

Sheet nanocarbon-Al_2O_3 composite powders were produced by vibratory milling using expanded graphite and Al_2O_3 powders as raw materials. The effect of different vibratory milling time on phase compositions and microstructure of the composite powders were investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM). Then sheet nanocarbon-Al_2O_3 composite powders were used as additives to produce low carbon Al_2O_3-C refractories which had a carbon content of 6%. The results showed that about 50nm thickness sheet nanocarbon and Al_2O_3 composite powders were produced via 15h milling with expanded graphite to Al_2O_3 powders weight ratio of 1:2. With the increasing of milling time, the (002) diffraction peaks of graphite wear off gradually and nano-sheet was desquamated from expanded graphite; It is beneficial to improve the bulk density, cold modulus of rupture(CMOR) and thermal shock resistance of Al_2O_3-C refractories when adding certain sheet nanocarbon-Al_2O_3 composite powders. The sample containing 0.5% sheet nanocarbon had a CMOR of 18.51MPa after 1000 ℃ heat processing in N_2 atmosphere, while sample without adding any sheet nanocarbon was only 12.35MPa; The residual cold modulus of rupture(CMOR_(TS)) of sample containing 1% sheet nanocarbon was 4.22MPa after thermal shock test, while that of sample without nanocarbon was only 2.18MPa.