Studies On The Inhibitor Of Mild Steel In Sulfamic Acid Solution

This paper studied respectively the corrosion velocity and inhibition efficiency of mildsteel in5%sulphamic acid with a few of compounds by weight-loss method, then severaltypes of compounds with good corrosion inhibition effect have been selected from which,including: cetylpyridinium bromide, thiourea, benzalkonium bromide, cinnamaldehyde.In these compounds cetylpyridinium bromide, thiourea, benzalkonium bromide,cinnamaldehyde were selected as research objects. I study the corrosion inhibition ofone-component corrosion inhibitor for mild steel in5%sulfamic acid solution by theweight-loss method and the electrochemical polarization curve analysis method. I obtain thethermodynamic data of the relational reaction. The results indicated that the single moleculelayer of these compounds adsorbed on the surface of mild steel and almost followedLangmiur isothermal equation. The adsorption procedure of cetylpyridinium bromide,thiourea, benzalkonium bromide, cinnamaldehyde was exothermic reaction, the adsorptionability and corrosion inhibition efficiency decreased with increasing temperature. The resultsof the electrochemical polarization curve show that: the selected compounds inhibit thecorrosion of mild steel in the solution of sulfamic acid. The corrosion inhibitor can inhibit theprocess of the anode and cathode potention, it is a mixed type inhibitor.According to the synergy principle, on the basis of one-component inhibitionexperiments, a composite and excellent corrosion inhibitor was composed by orthogonalmethod. The corrosion inhibition action of this composite corrosion inhibitor has beenevaluated by using weight-loss method, electrochemical polarization-curve method andscanning electron microscopy techniques. The results of the experiments show that: Thiscompound corrosion inhibitor of mild steel in sulphamic acid system has good inhibitioneffect. The inhibition efficiency of corrosion inhibitor reaches to98.95%， andanti-temperature, anti-acid, anti-time, anti-jamming performance is excellent. In the15%sulphamic acid with compound corrosion inhibitor, the corrosion rate of mild steel reaches to14xx. In the15%sulphamic acid with compound corrosion inhibitor, the corrosion rate ofmild steel reaches to14xx in20h.At the same times, the mild steel corrosion current reducesignificantly by adding compound corrosion inhibitor in the electrochemical experiments. Thecoverage of mild steel electrode surface is significantly improved. The SEM photos indicatedthat no signal of was found under different corrosion condition. It showed that the compositecorrosion inhibitor is an excellent corrosion inhibitor for mild steel in sulphamic acid solution.