In this paper, the nanoparticles (NPs) of magnesium oxide (nano-MgO) and silicon dioxide (nano-SiO₂) and ultrasonication on the properties of sodium silicate bonded sand (SSBS) were studied, and the quantity of NPs and ultrasonication time in their interaction with sodium silicate binder were optimized by orthogonal experiment. This research was conducted with sodium silicate as a part of two-component (sodium silicate–silica fume) binder system to be used for heat-cured sodium silicate bonded ceramic sands. The results of experiment indicated that the addition of NPs and ultrasonication promoted the continuity and density of the bonding bridge of sand samples, the optimal quantity of nano-MgO and nano-SiO₂ was 1.5% and 1.0% of sodium silicate binder, the optimal ultrasonication time was 15min, hot strength (σ₀), 4-h tensile strength (σ_4h) and 24-h tensile strength (σ_24h) of modified sand samples increased by 11%, 25% and 27%, and the residual strength (σ_800ºC) decreased by 28%. The different linear expansion coefficients between nano-MgO, the new phase Na₂Si₃O₇ and the sodium silicate system caused many cracks on the bonding bridge in the process of heating at 800°C and cooling, which resulted in the reduction of the residual strength of SSBS.

本文研究了氧化镁（nano-MgO）和二氧化硅（nano-SiO ₂）的纳米颗粒（NPs）及其对硅酸钠粘结砂（SSBS）性能的超声处理，并研究了其数量和超声处理时间。通过正交实验优化了它们与硅酸钠粘合剂的相互作用。这项研究是使用硅酸钠作为双组分（硅酸钠-硅粉）粘合剂体系的一部分进行的，该体系用于热固化的硅酸钠粘结陶瓷砂。实验结果表明，纳米颗粒的加入和超声处理促进了砂样结合桥的连续性和密度，纳米MgO和纳米SiO ₂的最佳添加量。为1.5％和硅酸钠粘合剂的1.0％，最佳的超声时间为15min，热强度（σ ₀），4小时拉伸强度（σ _4H）及24h的拉伸强度（σ _24小时改性砂样的）增加了11％，25％和27％，残余强度（_σ800ºC）降低了28％。纳米MgO，新相Na ₂ Si ₃ O ₇和硅酸钠体系之间的线性膨胀系数不同，在800°C加热和冷却的过程中，键桥上出现许多裂纹，从而降低了SSBS的残余强度。