β-Sialon/ZrN bonded corundum composites were synthesized using fused white corundum,alumina micro powder,zircon and carbon black by nitridation reaction sintering process. Phase composition and microstructure of the ...β-Sialon/ZrN bonded corundum composites were synthesized using fused white corundum,alumina micro powder,zircon and carbon black by nitridation reaction sintering process. Phase composition and microstructure of the synthesized composites were investigated by X-ray powder diffraction and scanning electronic microscope,and the formation process of the composites was discussed. The results show that the composites with different compositions can be obtained by controlling the heating temperature and contents of zircon and carbon black. The proper temperature to synthesize the composites is 1773 K.展开更多
Thermal shock resistant properties of reaction sintered bauxite-based β-Sialon bonded corundum have been investigated, and the results are compared with those of Al_ 2O_ 3 based counterpart. It is found they all ha...Thermal shock resistant properties of reaction sintered bauxite-based β-Sialon bonded corundum have been investigated, and the results are compared with those of Al_ 2O_ 3 based counterpart. It is found they all have very good thermal shock resistance. Their residual strength ratios after one thermal shock cycle at ΔT=1200℃ and ΔT=1350℃ are 61%~73% and 53%~65% respectively. Their critical temperature difference (TSR) is 600℃~800℃. TSR parameters are calculated based on thermal expansion, modulus of elasticity, and fracture toughness determined. The reasons for improving TSR of these composite materials are discussed.展开更多
The paper presents a new method to synthesize β-Sialon bonded corundum brick (β-SBCB) from Al-Si alloy directly and easily under 1430℃ , the volume expansion of reaction between Al powder and Nitrogen can help to e...The paper presents a new method to synthesize β-Sialon bonded corundum brick (β-SBCB) from Al-Si alloy directly and easily under 1430℃ , the volume expansion of reaction between Al powder and Nitrogen can help to establish the fast diffusion channel in Al-Si alloy; the suitable crystal seed of Si3N4 is helpful to the fast synthesis of β-Sialon.展开更多
In order to improve the anti-explosion performance ofρ-Al_(2)O_(3) bonded corundum castables,H_(2)O_(2) was added(0,0.025%,0.050%,0.075%,0.100%and 0.125%,by mass)as the anti-explosion agent.After mixing and casting,s...In order to improve the anti-explosion performance ofρ-Al_(2)O_(3) bonded corundum castables,H_(2)O_(2) was added(0,0.025%,0.050%,0.075%,0.100%and 0.125%,by mass)as the anti-explosion agent.After mixing and casting,specimens were prepared.Some specimens were cured at room temperature for 12 h and demoulded for the anti-explosion performance test at different temperatures(450,500,550,600,650,700,750 and 800℃);the other specimens were cured,dried and fired,and tested in terms of the apparent porosity,the density,the cold mechanical properties,the air permeability and the pore size distribution.The results show that:(1)with the increase of the H_(2)O_(2) addition,the anti-explosion performance of castables increases gradually,the average pore size increases gradually,and the density and the strength decrease gradually;(2)by comprehensive consideration,the appropriate addition of H_(2)O_(2) shall be within 0.075%.展开更多
In order to investigate the effect of zirconia corundum on the preparation of chrome corundum castables,samples were prepared using tabular corundum,white fused corundum,active alumina micropowder,chromium oxide micro...In order to investigate the effect of zirconia corundum on the preparation of chrome corundum castables,samples were prepared using tabular corundum,white fused corundum,active alumina micropowder,chromium oxide micropowder and fused ziconia corundum particles as the main raw materials,and pure calcium aluminate cement as the binder.The effects of the fused zirconia corundum particles addition(1-0.5 mm,0,4.5%,9%,and 18%,by mass)on the linear change rate,the apparent porosity,the cold modulus of rupture,and the thermal shock resistance of chrome corundum castables were studied,and the microstructure of the samples was analyzed.The results show that:(1)with the zirconia corundum addition increasing,the permanent linear change on heating of the samples gradually increases,the apparent porosity gradually increases,the cold modulus of rupture gradually decreases,and the thermal shock resistance gradually increases;(2)according to SEM,it can be found that the phase transformation of ZrO2 after heat treatment leads to a large number of microcracks in the material.On one hand,the cold modulus of rupture of the material is reduced;on the other hand,the thermal shock resistance of the material is improved.展开更多
基金Project(50274021) supported by the National Natural Science Foundation of China and Baoshan Iron and Steel Co., Ltd.
文摘β-Sialon/ZrN bonded corundum composites were synthesized using fused white corundum,alumina micro powder,zircon and carbon black by nitridation reaction sintering process. Phase composition and microstructure of the synthesized composites were investigated by X-ray powder diffraction and scanning electronic microscope,and the formation process of the composites was discussed. The results show that the composites with different compositions can be obtained by controlling the heating temperature and contents of zircon and carbon black. The proper temperature to synthesize the composites is 1773 K.
文摘Thermal shock resistant properties of reaction sintered bauxite-based β-Sialon bonded corundum have been investigated, and the results are compared with those of Al_ 2O_ 3 based counterpart. It is found they all have very good thermal shock resistance. Their residual strength ratios after one thermal shock cycle at ΔT=1200℃ and ΔT=1350℃ are 61%~73% and 53%~65% respectively. Their critical temperature difference (TSR) is 600℃~800℃. TSR parameters are calculated based on thermal expansion, modulus of elasticity, and fracture toughness determined. The reasons for improving TSR of these composite materials are discussed.
文摘The paper presents a new method to synthesize β-Sialon bonded corundum brick (β-SBCB) from Al-Si alloy directly and easily under 1430℃ , the volume expansion of reaction between Al powder and Nitrogen can help to establish the fast diffusion channel in Al-Si alloy; the suitable crystal seed of Si3N4 is helpful to the fast synthesis of β-Sialon.
文摘In order to improve the anti-explosion performance ofρ-Al_(2)O_(3) bonded corundum castables,H_(2)O_(2) was added(0,0.025%,0.050%,0.075%,0.100%and 0.125%,by mass)as the anti-explosion agent.After mixing and casting,specimens were prepared.Some specimens were cured at room temperature for 12 h and demoulded for the anti-explosion performance test at different temperatures(450,500,550,600,650,700,750 and 800℃);the other specimens were cured,dried and fired,and tested in terms of the apparent porosity,the density,the cold mechanical properties,the air permeability and the pore size distribution.The results show that:(1)with the increase of the H_(2)O_(2) addition,the anti-explosion performance of castables increases gradually,the average pore size increases gradually,and the density and the strength decrease gradually;(2)by comprehensive consideration,the appropriate addition of H_(2)O_(2) shall be within 0.075%.
文摘In order to investigate the effect of zirconia corundum on the preparation of chrome corundum castables,samples were prepared using tabular corundum,white fused corundum,active alumina micropowder,chromium oxide micropowder and fused ziconia corundum particles as the main raw materials,and pure calcium aluminate cement as the binder.The effects of the fused zirconia corundum particles addition(1-0.5 mm,0,4.5%,9%,and 18%,by mass)on the linear change rate,the apparent porosity,the cold modulus of rupture,and the thermal shock resistance of chrome corundum castables were studied,and the microstructure of the samples was analyzed.The results show that:(1)with the zirconia corundum addition increasing,the permanent linear change on heating of the samples gradually increases,the apparent porosity gradually increases,the cold modulus of rupture gradually decreases,and the thermal shock resistance gradually increases;(2)according to SEM,it can be found that the phase transformation of ZrO2 after heat treatment leads to a large number of microcracks in the material.On one hand,the cold modulus of rupture of the material is reduced;on the other hand,the thermal shock resistance of the material is improved.
