Studies On The Inhibitor Of Aluminum In Hydrofluoric Acid Solution

The metal aluminum has been widely applied as reactors, dryers and heat changers to every field of our national economy, relying on the excellent performance of electrical and thermal conductivity, quality and corrosion resistance. Corrosion of aluminum is caused by low electric potential of safety zone, so the research on aluminum inhibitors has gradually expanded. The mass of the researches on aluminum inhibitors in hydrofluoric acid have been taken earlier. Due to the high cost and limitations of temperature and pollution, a new composite corrosion inhibitor with better inhibition effect, better temperature and impurity resistance and low price is needed.This paper determines inhibition effect of aluminum in 5% hydrofluoric acid with hundreds of inorganic and organic compounds by using weight-loss method, and chooses several compounds with better inhibition effect. After studying and analyzing the inhibition mechanism of hexadecylpyridinium bromide hydrate, furfural and STPP, a serial of thermodynamic parameters have been calculated by adsorption theory and electrochemical polarization-curve method. The results indicated that hexadecylpyridinium bromide hydrate and furfural belong to admixture type inhibitors which almost follow Langmuir isothermal equation, and the single molecule layer of these compounds adsorbed on the surface of aluminum within the temperature range.This paper obtains a composite corrosion inhibitor with excellent performance by using orthogonal experiments. The corrosion inhibition has been evaluated by using weight-loss method, electrochemical polarization-curve method, quantum mechanics, EIS and scanning electron microscopy techniques. It proves that this admixture type inhibitor decreases corrosion current and increases activation energy, resistance of acid, temperature and time. The film's capacitance decreases and surface coverage increases after appending this composite corrosion inhibitor with no sign of corrosion. It reveals that the composite corrosion inhibitor is excellent in hydrofluoric acid medium.