炭化温度对竹炭微观结构及电性能的影响

炭化温度对竹炭微观结构及电性能的影响

  • 摘要: 将5年生毛竹竹材在氮气氛下进行炭化处理,采用SEM、TGA、XRD、EDXA等研究炭化温度对竹炭微观结构、元素含量及其电阻率的影响。结果表明:随着炭化温度的升高,竹炭微观结构收缩程度增加,竹材经500℃、750℃和1000℃炭化后,其横切面的收缩率分别是21%、38%和40%,微晶结构趋于向石墨有序化的中间状态变化。竹炭不同部位的C元素含量和电阻率不同,并随温度变化而变化。500℃时C元素的质量分数为:表层(49.25%)<内部(91.43%)<内表层(95.53%)。竹炭电阻率在750℃发生明显的突变,表层、内部和内表层的电阻率比500℃时降低98倍~187倍。随着温度的升高,竹炭导电性增强的原因是由于石墨微晶尺寸增大和灰分含量降低所致。

     

    Abstract: Five year old bamboo was carbonized under N2 atmosphere. The effect of carbonization temperature on microstructure, elemental content and resistance were investigated by TGA, SEM, EDXA and XRD. Results show that shrinkage of bamboo during carbonization increases with increasing carbonization temperature, the section shrinkage is 21%, 38% and 40% for 500℃, 750℃ and 1000℃ respectively. The microcrystalline structure of bamboo charcoal tends to a transitional state that leads to graphite. The carbon content and resistance of bamboo charcoal depend on carbonization temperature and radial location. The carbon content of bamboo charcoal carbonized at 500℃ increases from the outer to inner surfaces. An abrupt decrease of resistance is found at 750℃, which shows a 98 to 187 times decrease from outer to inner surface as compared with those values at 500℃. The electrical conductivity of the charcoal is directly related to the carbonization temperature because increasing carbonization temperature increases the crystallite size and decreases ash content, both of which are favorable for increasing the conductivity.

     

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