Study Of The La-Cu System Electromagnetic Shielding Effectiveness

With the development of modern high-tech, the problem that electromagnetic interference (EMI) and electromagnetic compatibility (EMC) caused by electromagnetic wave has increasingly worried. Electromagnetic pollution has became the forth hazard to human health, following noise pollution, air pollution and water pollution. A effective type of the electromagnetic shielding materials was studied and exploited to meet the demand of international for preventing the environment and human from electromagnetic pollution, preventing the information of electromagnetic wave from leakiness. Because the important role of electromagnetic shielding materials in community living, economic development and national defence construction, the more and more attention make it a importance problem.A La-Cu system electromagnetic shielding paint doped rare earth La was studied. Its phase structure was analyzed by X-ray diffraction (XRD).The influences of the different doping on conductibility and electromagnetic shielding effectiveness of the coating were analyzed by impedance characteristic.The results of XRD spectra show that the whole peaks are characteristic peaks of Cu and La without other peak. The peak moved from lower angle along with the increasing of content rare earth La quantity.The testing results of AC impedance show that samples have lower impedance, which decrease with the increasing of content rare earth La. The amount of rare earth La at the quality of 16.7% for the copper, the lowest grain and grain boundary resistance of samples are 16.19Ω,67.80Ω. the max grain capacitance of samples is 1.13×10-5F·cm-1, the max conductivity of samples is 190.49 (Ω·cm)-1, the shielding effectiveness achieve 89 dB at the range of frequency 30 MHz-1.5 GHz, the better conductibility and electromagnetic shield efficiency of samples can be obtained.