Effects of B_4 C and Si Antioxidant on Oxidation Resistance of Low-carbon MgO-C Brick
摘要
Low-carbon MgO-C specimens with dimension of φ36 mm×36 mm were prepared using fused magnesia,flake graphite and carbon black as main starting materials,thermoplastic phenolic resin as binder,hexamethylene tetramine as curing agent,Si powder (w(Si)80%,particle size 0.074 mm) and B4C (d90=36.5 μm) as antioxidant,pressing under 200 MPa and drying at 200 ℃ for 24 h.The oxidation resistance tests were conducted at 600 ℃,1 000 ℃ and 1 400 ℃ for 2 h,respectively.Effects of B4C and Si antioxidant on oxidation resistance of low-carbon MgO-C brick were studied by comparing the areas of the decarburized layers.The results show that:(1) When Si powder addition is 3%,at 600 ℃ and 1 000 ℃,the specimens with 0.5% B4C perform good oxidation resistance;at 1 400 ℃,the oxidation resistance of the specimens is improved with the addition of B4C increasing,and that of the specimen with 0.7% B4C is the best.(2) When B4C addition is 0.5%,at 600 ℃ and 1 000 ℃,the oxidation resistances of the specimens with 3% and 5% Si powder are similar,which are better than that of the specimen with 1% Si powder;and at 1 400 ℃,the oxidation resistance of the specimens is improved obviously with the addition of Si powder increasing,and that of the specimen with 5% Si powder is the best.(3) Based on the results,it is believed that the low-carbon MgO-C brick with 0.5% B4C and 3% Si powder performs the best oxidation resistance.