Low carbon Al2 O3-C refractories specimens were prepared with tabular alumina (3.0 -1.0,1.0 -0.5,0.6 -0.2,≤0.3,≤0.045 and ≤0.02 mm),active alumina micropowder (≤2 μm)and silicon (≤0.045 mm)as main raw materials.Nano carbon black (N220)and natural graphite flake (≤0.074 mm)were adopted as the carbon sources.The specimens were treated at 800,1 000,1 200 and 1 400 ℃under coke embedded atmosphere.The effects of additions of nano carbon black and graphite flake on mechanical properties and thermal shock resistance of the specimens were studied.Their mechanical properties were measured by three-point bending test and thermal shock resistance was determined by water quenching method.The phase compositions of the specimens were analyzed with X-ray diffraction and microstructures were observed through FESEM.The results reveal that:(1 )the strengths of Al2 O3 -C refractories with these two carbon sources show no big differences when coked at lower than 1 000 ℃;when coked at over 1 200 ℃,the strengths of the specimens with graphite added are much higher than those of the specimens containing carbon black due to much more silicon carbide whiskers formed;(2) since the nano carbon black has small particle size,they can be filled into interstice of Al2 O3 particles to form the nano carbon network structure,absorbing and relieving the thermal stress generated from expan-sion and contraction and reducing the thermal expansion coefficient of the specimens,thus their thermal shock resistance is better than that of the specimens containing graphite;(3)low carbon Al2 O3-C refracto-ries with good mechanical properties and excellent thermal shock resistance can be prepared with combi-nation of nano carbon black and graphite flake.%采用板状刚玉（3．0～1．0、1．0～0．5、0．6～0．2、≤0．3、≤0．045和≤0．02 mm ）、活性氧化铝微粉（≤2μm）、单质硅（≤0．045 mm）为主要原料，引入纳米炭黑（N220型）或天然鳞片石墨（≤0．074 mm）为碳源，在埋焦炭条件下经800、1000、1200和1400℃处理制备了低碳 Al2 O3－C 耐火材料。对比研究了炭黑和鳞片石墨不同加入量对试样的力学性能和抗热震性的影响。采用三点弯曲法研究两种碳源对材料力学性能的影响，采取水淬冷法研究材料的抗热震性，利用 X 射线衍射仪检测材料的物相组成变化，通过场发射扫描电子显微镜观察材料的显微结构。结果表明：1）当铝碳材料处理温度低于 1000℃时，碳源种类对其强度影响不明显；当处理温度高于 1200℃时，由于更多碳化硅晶须的生成，添加石墨试样的强度远高于添加纳米炭黑的铝碳材料。2）纳米炭黑粒径小，易填充于氧化铝颗粒间隙并形成纳米碳网络，有利于吸收和平衡热膨胀和收缩过程中产生的热应力，降低材料的热膨胀系数，其热震后强度保持率高于含石墨的铝碳材料。3）通过纳米炭黑与微米鳞片石墨的有效复合可以制备出强度高，抗热震性好的低碳铝碳耐火材料。
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