The subject of this thesis involved potentiostatic nd investigation of the corrosion behaviour of Inconel (6OO) specimen in sulphuric acid. The general pattern and the experimental techniques used could be classified into three different aspects as follows: 1. The corrosion behaviour of Inconel (600)in a number of concentrations of H2SO4 solutions from the polarization curves over a wide range of potentials (-1.0 to + 1.4volt). 2. The inhibiting effect of variour, additives (i.e. , nitric acid, thiourea, sodium chloride and hydrochloric acid) at different concentrations on the corrosion Inconel (600) specimen in the sulphuric acid solution.3. The of the corrosion behavior of the Inconel (600) in 2x10-² mol dm-³ hydrochloric acid solution at five different temper at ur es . The aims that have been satisfied in the complete programme of this research may be condensed into the following: 1. On the addition of thiourea or sodium chloride or hydrochloric acid to sulphuric acid solution, values of the corrosion potential (Ec) for the Inconel (600) specimen at a given temperature moved to less negative potentials with increasing their concentrations in the H2SO4 solutions. The effect of the various inhibi tors , however , i n shifting values of EC to less negative potentials could be arranged in a sequence as: thiourea > sodium chloride≈ hydrochloric acid. Nitric acid addi tion to sulphuric acid solution increased the tendency of Inconel (600)for corrosion and such tendency decreased as the nitric acid concentration protection efficiency (p) values were increased. concentration increased. 2.The highest, when nitric acid was present in the H2So4 solution at 313 k. At lower temperatures ( ~ 293 k) thiourea was the most e f f i c i e n t and s u i t a b l e the i n h i b i t o r p a r t i c u l a r l y a t a concentration of 10-² mol dm-³ 3.the coverage (θ) of the Inconel (600) surface by the various inhibitors was determined from the current densities at constant potential in the presence and absence of the inhibitor in the acid solution. A linear relationship was found to exist between the values of C/e and the corresponding inhibitor concentrations © indicating the inhibition action to operate through the adsorption mechansim. 4. The thermodynamic feasibility of inhibition has been judged from the change in the Gibbr free energy of the inhibitor adsorption on the Inconel (600) surface 5. The rate (r) of Inconel (600) corrosion in the H2S04 solution increased generally with the rise of temperature from 293 to 313 K and the behaviour followed the Arrhenius equation: r = A exp(-E/RT) where E is the energy of activation for the corrosion, and A is the pre—exponentlal factor. 6. A linear relationship was found to exist between the experimental values of log A . and the corresponding values of E which could be expressed as Log A = m E + I such a relationship is termed a"compensation effect" which is known describe the behaviour of metals in various tarnishing reactions. The E value for the Inconel (600) in the H2SO4 solution was 40.41 kJ mol-¹ . The presence of nitric acids and sodium chloride decreased E values significantly E and log A increased considerably in the presence of thiourea in H2SO4 solution. Thus the kinetic results provided a reasonable support for the variation of the protection efficiency values which have been obtained under various experimental conditions of the present work . The k i net i c r esult indicated that the nature of the corrosion reactions which occurred at Inconel (600)/ sulphuric acid interface in the presence of nitric and hydrochloric acids differed than those which proceeded in the presence of thiourea or sodium chloride or in the absence of any inhibitor. Such a , difference may be ascribed to the effects of several factors including the number of reaction steps the nature of the rato- determining step as well as to certain other kinetic parameters.