The Effects Of Al₂O₃ And ZrO₂ Nanopowders Addition On Properties And Structure Of High Chrome Brick

Because of the excellent thermomechanical property, high chrome brick is widely used as lining brick of Texaco type coal gasifier.The effects of Al2O3 and ZrO2 nanopowders on rheological behavior of the High chrome brick matrixes, sintering characters, high temperature properties of Al2O3 and ZrO2 nanopowders composite high chrome brick were studied. The results show that:When Fs-10 addition is 1%, shear viscosity of matrix first decreases and then increases, with Al2O3 nanopowder content increase. When the addition of Al2O3 nanopowder is 0.5%, the shear viscosity of matrix is the lowest value of 1.7Pa·S; Shear viscosity of matrix first decreases and then increases with ZrO2 nanopowder content increase, when the addition of ZrO2 nanopowder is 0.5%, the shear viscosity of matrix is the lowest value of 1.3Pa·S.The proper addition of Al2O3 and ZrO2 nanopowders can promote sintering, make the sintering temperature decrease 100℃～150℃and improve room temperature properties of high chrome brick. The optimal addition of Al2O3 nanopowder and ZrO2 nanopowder respectively is 0.5% and 1.5%. Compared with the samples without nanopowders which are fired at 1550℃, the apparent porosity of high chrome brick after 1400℃firing with the addition of 0.5wt% Al2O3 nanopowder decreases from16.6% to 14.4%, cold modulus of rupture increases from 28.8Mp to 31.7MPa, cold crush strength increases from 43Mp to 70Mpa. The apparent porosity of high chrome brick after 1400℃firing with the addition of 1.5% ZrO2 nanopowder decreases from 16.6% to 14.9%, cold modulus of rupture increases from 28.8MPa to 34.6Mpa. The properties are similar to the sintering properties of high chrome brick without nanopowders after 1550℃firing.The hot modulus of rupture (HMOR), thermal shock resistance (TSR) and the residual strength ratio of high chrome brick increase first and then decrease with the Al2O3 nanopowder content increase. Compared with the sample without nanopowder, the hot modulus of rupture of high chrome brick with 1.5% Al2O3 nanopowder addition increases from 25.5MPa to 28.7MPa, the residual strength of high chrome brick with 0.5% Al2O3 nanopowder addition increases from 8.8MPa to 11.5MPa. The residual strength ratio of high chrome brick with 1% Al2O3 nanopowder addition increases from 29.1% to 34.8%; The hot modulus of rupture (HMOR), thermal shock resistance (TSR) and the residual strength ratio of high chrome brick with ZrO2 nanopowder increase first and then decreasewith the ZrO2 nanopowder content increase. The high chrome brick with 1.5% ZrO2 nanopowder addition behaves the best, compared with sample without nanopowder addition, hot modulus of rupture (HMOR) increases from 25.5MPa to 36.6MPa, the residual strength ratio increases from 29.1% to 37.4%, the residual strength increases from 8.8MPa to 13.8MPa.