The technical Electrochemical Frequency M odulation (EFM ) is presented, as a new method for the evaluation of the corrosion rate and electrochemical analysis of materials. The technique consists in the generation of two potentials of sinusoidal type of frequencies 2Hz and 5Hz with amplitude of 10mV added and applied simultaneously to the sample evaluated front of the corrosion, measuring to the exit the answer in current of the harmonic and intermodulation frequencies of the applied signs. To validate this technique they were carried out tests of curved of polarization Tafel, on test tubes of concrete Portland with several carbonatacion levels and these results were confronted with those obtained in the technique (EFM ).