The dissolution of Cu and Zn, and of three Cu Zn alloys in solutions of different concentrations of HNO 3 was studied by the thermometric technique. The variation of Δ T (i.e. T m − T i ) and the reaction number (R.N.) with the concentration of the attacking acid followed the relations: Δ T = A 1 ( C − C 0 ) and R . N . = A 2 C n , successively. Based on the values of the constants A 1, C o , A 2 and n, the rate of dissolution of the different materials was found to increase in the order: Cu < Alloy I (70.5%Cu) < Alloy III (58.00%Cu) < Alloy II (62.00%Cu) < Zn. A break was noted in the thermometric curves of Alloy I. This was due to the primary attack on the Zn-component of the alloy, and was confirmed by studying the effect of the initial temperature, T i , and the area/volume ratio on the shape of the curves, as well as by chemically analysing the corroding solution for both Cu 2+ and Zn 2+. The effect of the concentration of HCl, H 2SO 4, H 3PO 4 and of their salts on the reaction number of the alloys in 4N HNO 3 was examined in detail. The adsorption of the foreign acid anion on the metal surface retarded dissolution. Inhibition increased in the succession: Cl − < HSO 4 − < H 3PO 4 −. The alloys were not affected by cold 4N HCl, H 2SO 4 or H 3PO 4. Attack could be initiated in the case of the first two acids through the addition of KNO 3. The thermometric curves were characterized by long incubation periods, by sharp temperature maxima and by the rapid decrease of temperature thereafter. This supported the conclusion that attack was of the pitting rather than of the general type. Because of stronger anion adsorption, attack in 4N H 2SO 4 was much lower than in 4N HCl. No attack was recorded in 4N H 3PO 4. Parallelism between corrosion assessment by the thermometric technique and by the weight loss method was established. † Permanent address: Laboratory of Electrochemistry and Corrosion, National Research Centre, Dokki, Cairo, Egypt.