Chloride-contaminated Pore Solution Research Articles

Pitting initiation on 304 stainless steel in a chloride-contaminated pore solution under alternating temperature conditions

Abstract Pitting initiation on 304 stainless steel grades was investigated in alternating temperature pore solutions to simulate pitting on stainless steel rebar in a tropical marine environment. The results suggested that a larger amplitude of alternating temperature heavily doped the passive film, reduced the film’s thickness and increased the (Fe3+ox + Fe3+hy)/Fe2+ox and Cr3+hy/Cr3+ox ratios in the film. Alternating temperatures more significantly degraded the passive film and intensified the pitting sensitivity on the stainless steel when compared with the average temperatures of the alternating temperature cycles. More pitting initiation sites were observed on the samples that experienced the 22–60 °C and 22–70 °C alternating temperature cycles than their counterparts in 50 °C and 60 °C solutions, respectively.

On the novel approach of sacrificial cathodic protection of mild steel in simulated concrete pore solution and concrete mortar by high phosphorus pig iron anodes

The effectiveness of high phosphorus pig iron (1.5 wt% P, 3.5 wt% P, and 8.0 wt% P) as sacrificial anode for the cathodic protection of mild steel was investigated in simulated concrete pore solution and concrete mortar. Electrochemical tests were carried out in both chloride-free and chloride-contaminated pore solution under freely aerated and deaerated environments. Linear and dynamic polarization, electrochemical impedance spectroscopy and zero resistance ammeter tests were performed to compare the electrochemical behavior of the pig iron samples to the mild steel. Laboratory and field tests were also conducted by galvanically coupling the mild steel to the pig iron samples in the concrete mortar and monitoring the polarization shift. The polarization results indicate that all three different pig iron samples show more active potential as compared to the mild steel in both chloride-free and chloride contaminated pore solutions. The open circuit potential and polarization resistance for all the pig iron samples decrease with an increase in the P content. The more active galvanic potential and positive galvanic current density for the pig iron and the mild steel couple show the effectiveness of the pig iron as a sacrificial anode in simulated concrete pore solution. The laboratory and field studies also suggest that the 100 mV polarization shift criterion has been established, and the pig iron samples are effective in preventing the corrosion of the mild steel in concrete. The first time use of iron based sacrificial anode for the cathodic protection of reinforcing steel embedded in concrete defines the novelty of the present work.

Doping engineering of V-TiO2 for its use as corrosion inhibitor

Now-a-days, use of non-chromium compounds as corrosion inhibitors in anti-corrosive paints for metals is taking center stage of research to protect environment from hazardous compounds. The present study deals with the synthesis of chromium free vanadium doped titanium dioxide and their inhibition efficiency towards corrosion prevention of reinforced bar (rebar) in chloride contaminated pore solution. The doping efficiency of the xV-TiO2 and subsequently their inhibition characteristics have been analyzed with the help of electrochemical measurements. Doping of about 2% V enables to achieve an excellent inhibition efficiency of ∼90%. The formation of protective nanometric adsorptive layer on the rebar till an optimal content of the inhibitor provides corrosion protection against chloride environment.

Electrochemical and microstructural analysis of azomethine polyamides as inhibitor for rebar corrosion under chloride contaminated pore solution

Electrochemical and microstructural analysis of azomethine polyamides as inhibitor for rebar corrosion under chloride contaminated pore solution

The nature of rusts and corrosion characteristics of low alloy and plain carbon steels in three kinds of concrete pore solution with salinity and different pH

Correlation of corrosion characteristics and nature of rusts on low alloy (LA) and plain carbon (PC) steels exposed in simulated concrete pore solution of different pH is studied. Rusts formed under wet/dry conditions are examined by Raman spectroscopy and X-ray diffraction. LA rust is more adherent compared to PC as confirmed by measurement of weight in gain and electrochemical studies. EIS results show improvement in protective properties of steels with passage of time. Both steels are found prone to pitting attack in chloride contaminated pore solution. Rebars embedded in concrete exhibit same trend as recorded in solution exposure tests.