Effects of MgO and La2O3 Composite Additives on Microstructure of Nano-Microcrystalline Alumina Ceramics
The nanocrystalline alumina abrasive,with its excellent versatility and high-precision grinding capability,has become a cost-effective choice for various applications in fields such as mechanical manufacturing,bearings,molds and automobiles.In this study,nano microcrystalline alumina was synthesized by sol-gel process,with boehmite(γ-AlOOH)as raw material,MgO and La2O3 as additives.The effects of MgO and La2O3 additives on the phase transformation,phase composition,microstructure and mechanical properties of nanocrystalline alumina were investigated by differential scanning calorimetry,X-ray diffraction,scanning electron microscopy and ab initio molecular dynamics simulation.The results show that MgO and La2O3 composite additives can reduce the transformation temperature of alumina from the intermediate phaseθ-Al2O3 to α-Al2O3 from 1 257℃to 1 105 ℃,lower the densification temperature of the material from 1 600℃to 1 350℃,and reduce the grain size of nanocrystalline alumina from 1.04 mm to 120 nm,thus realizing the low-temperature dense sintering.
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