材料期刊网

为了研究Al-Zn复合低碳MgO-Al2O3-C材料在不同温度埋炭热处理过程中的变化及其对材料抗氧化性的影响,以电熔镁砂、鳞片石墨、Al粉和Zn粉为原料,分别制成Al复合和Al-Zn复合低碳MgO-Al2 O3-C试样,经200℃烘烤12 h后,分别在600、1000、1 200和1 500℃埋炭热处理3h,然后在空气气氛中进行室温至1 500℃的热重分析,并测量热重试验后试样的氧化层厚度.结果表明:1)在600℃埋炭热处理过程中,试样因树脂挥发变得多孔疏松,导致其抗氧化性变差.2)1 000～1 500℃埋炭热处理后,Al复合低碳MgO-Al2O3-C试样因原位生成非氧化物而致密化,抗氧化性随埋炭热处理温度的升高而增强.而Al-Zn复合试样在因原位生成非氧化物而致密化的同时,也因Zn的挥发而疏松化;并且随埋炭热处理温度的升高,疏松化超过致密化.因此,其抗氧化性随埋炭热处理温度的升高而变差.

In order to research the change and the oxidation resistance of Al-Zn bearing low carbon MgOAl2O3-C materials during carbon embedded treatment at different temperatures,Al or Al-Zn bearing low carbon MgO-Al2O3-C specimens were prepared using fused magnesia,flake graphite,Al powder and Zn powder as starting materials,baking at 200 ℃ for 12 h,and carbon embedded firing at 600,1 000,1 200,and 1 500 ℃ for 3 h,respectively.Then the thermogravimetric analysis from room temperature to 1 500 ℃ in air was carried out,and the oxidation layer thickness of the specimens was also determined.The results show that:(1) during carbon embedded firing at 600 ℃,the specimens become porous due to the volatilization of resin,and the oxidation resistance becomes poor;(2)after carbon embedded firing at 1 000-1 500 ℃,Al bearing low carbon MgO-Al2O3-C specimens become dense due to the in-situ formation of non-oxides,the oxidation resistance increases with the temperature rising;for Al-Zn bearing low carbon MgO-Al2O3-C specimens,there is also in-situ formation of non-oxides,causing densification of specimens,however,the volatilization of Zn leads to a loose structure,and the loosening exceeds the densification with the temperature rising,so the oxidation resistance gets worse.