Measurement and Calculation Method for the Resistivity of Conductive Materials Based on OCTEM

新开发的导电材料亟需掌握其电阻率特性，但是由于样品数量的稀缺以及拉丝工艺的困难，采用强迫电流法测量导电材料电阻率时极易造成电路短路。为此，本文提出了基于等值反磁通瞬变电磁法测量导电材料电阻率方法。首先，为了避免关断电磁振荡和环境噪声，提高信噪比，构建早期和晚期可信时刻线，采用二次场响应曲线和早晚最可信时刻线的扇形面积作为标本电阻率灵敏系数；然后，采用最小二乘拟合方法得到标本电阻率与灵敏系数的逼近函数，通过逼近函数计算得到样本的电阻率；最后，通过铜、铁、铝、钨以及合金导电材料的测试分析结果表明该方法计算得到的电阻率与真实电阻率的RMSE达到了10−9量级。Newly developed conductive materials urgently need to be characterized in terms of their resistivity, but due to the scarcity of samples and the difficulty of the drawing process, it is very easy to short-circuit circuits when measuring the resistivity of conductive materials using the forced-current method. For this reason, this paper proposes a method for measuring the resistivity of conductive materials based on the opposing coils transient electromagnetic method. First, in order to avoid turn-off electromagnetic oscillations and environmental noise and to improve the signal-noise ratio, early and late plausible moment lines were constructed, and the sector area of the secondary field response curve and the early and late most plausible moment lines were used as the specimen resistivity sensitivity coefficients; Then, the approximation function of the specimen resistivity to the sensitivity coefficient was obtained using the least squares fitting method, and the resistivity of the sample was calculated from the approximation function; Finally, the results of testing and analysis of copper, iron, aluminum, tungsten, and alloy conductive materials show that the resistivity calculated by this method has an RMSE of 10−9 orders of magnitude with respect to the true resistivity.