石墨化处理对炭炭复合材料磁电阻特性的影响研究  

Influence of graphitization treatment on the characteristic of magnetoresistance of carbon-carbon composites

作　　者：邓海金[1] 李明[1] 孙立[1] 王玉泉[1] 

机构地区：[1]北京清华大学材料科学与工程系,北京100084

出　　处：《新型炭材料》2003年第2期89-94,共6页New Carbon Materials

基　　金：清华大学材料科学与工程研究院985基金(ZX707)

摘　　要：　对不同温度石墨化处理得到的炭 炭复合材料的磁电阻特性进行了研究。结果表明:1)实验材料出现最大磁电阻的位向均为45° 135°,炭 炭复合材料磁电阻—位向关系不受石墨化处理温度、外磁场强度、测量温度等因素的影响。2)在同一磁场强度情况下,样品磁电阻与测量温度(5K～300K)呈线性关系变化,温度越高磁电阻越低。并且较低石墨化温度处理的样品在一定温度以上磁电阻降低为0,不再变化;2880℃石墨化处理的样品在一定温度以下出现"磁阻饱和值"。3)磁电阻—测量温度曲线回归方程的斜率项随热处理温度的增加而降低,而截距项随热处理温度的增加而增加。4)测量温度相同时,磁电阻随外加磁场强度的增大而增大,在低场(小于1.2T)下,呈现二次函数关系,场强高于1.2T后,磁电阻—磁场强度关系为线性。不同磁场强度下,随石墨化处理温度的提高,磁电阻也增大。The magnetoresistance characteristics of C/C composites graphitized at different heat treatment temperature (HTT) were investigated. The magnetoresistance of C/C composites exhibits a maximum at 45degrees orientation angle. HTT, intensity of the magnetic field (H) and the measuring temperature (MT) do not change the profile of the magnetoresistance-orientation curves. Magnetoresistance-temperature curves in the same magnetic field are straight lines with negative slopes. The magnetoresistance of samples formed at lower HTT is zero when MT is high enough. However, the magnetoresistance of the sample formed at = of 2880degreesC shows a saturated value when NU is low enough. From the fitted straight line from magnetoresistance-temperature curves, it is found that the slope decreases and the intercept increases with increasing HTT. The magnetoresistance of C/C composites increases with the increasing magnetic field intensity at the same MT. The curves are parabolic when H is less than 1.2 T and straight when H is higher than 1.2 T. Magnetoresistance increases with increasing HTT in any intensity of the magnetic field.

关 键 词：石墨化处理 炭/炭复合材料 磁电阻特性 磁场强度 

分 类 号：TB332[一般工业技术—材料科学与工程]