The effect of temperature ( 30,40,50,and 600C) on the polarization resistance (Rp) has been
analyzed for the corrosion of carbon steel in 1,3, and 5N HCl solution in absence & presence of
phenylthiourea(PHTU) as corrosion inhibitor.The polarization resistance was measured at above
mentioned conditions using BETACRUNCH program developed by Green and Gandi[Green,1982]. i.e; Values of applied current densities at potentials of +20,+10,-10 mv and then -20,+10,-10mV(SCE) from corrosion potentials were used to obtain corrosion parameters: iCorr ,ba bc followed by applying the equation: Rp = ( ba bc )/ 2.303 x iCorr.( ba + bc ).It is observed that: (i) for a certain acid concentration the polarization resistance decreased with increase in temperatureand/or decrease in inhibitor concentration.(ii) for a certain temperature, the polarization resistance decreases with an increase in acid concentration in presence and absence of inhibitor.