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研究了铝碳耐火材料中多壁碳纳米管(MWCNTs)在添加硅和硅微粉条件下的结构演变以及添加单质硅、硅和硅微粉对材料性能的影响。结果表明:高温下材料内单质硅与二氧化硅反应,导致大量的SiO(g)形成,加快了800℃以上MWCNTs的结构演变进程,促进MWCNTs蚀变为SiC晶须。正是由于SiC晶须形成,添加硅和硅微粉铝碳耐火材料经1 400℃处理后的抗折强度达到22.56 MPa,而单独添加单质硅的试样仅为19.24 MPa。然而,对于材料的抗热震性来说,未添加硅微粉的试样热震后强度保持率为43.51%,明显高于硅微粉试样的28.65%,这主要是由MWCNTs有助于提高材料的韧性,而Si C晶须主要起到增强的作用。
The structural evolution of multiwalled carbon nanotubes (MWCNTs) in aluminum-carbon refractories under the addition of silicon and silicon powders and the effect of addition of silicon, silicon and silicon powders on the properties of the materials were investigated. The results show that the reaction of elemental silicon with silica at high temperature leads to a large amount of SiO (g) formation, which accelerates the structural evolution of MWCNTs above 800 ℃ and promotes the alteration of MWCNTs into SiC whiskers. Due to the formation of SiC whiskers, the flexural strength of the refractories with silicon and silicon microalloyed aluminum-carbon refractories after heat treatment at 1 400 ℃ reached 22.56 MPa, while that of the samples with only added silicon alone was only 19.24 MPa. However, for the thermal shock resistance of the material, the strength retention after heat shock of the sample without silica fume was 43.51%, which was significantly higher than that of the sample of silica fume by 28.65%, mainly because the MWCNTs was helpful to improve the material Toughness, while Si C whiskers mainly play an enhanced role.