Corrosion behaviour in alkaline medium of zinc phosphate coated steel obtained by cathodic electrochemical treatment

A system for printing a three-dimensional object is provided. The system can include at least one print head configured to receive a continuous fiber and at least partially encase the continuous fiber with a formation material to create a composite material. The at least one print bed can be configured to move in at least six different degrees of freedom. The system can also include at least one print bed comprising a printing surface onto which the composite material may be selectively applied to form a work piece. The at least one print head can be positioned relative to the at least one print bed and configured to advance print media thereon.

Integrated robotic 3d printing system for printing of fiber reinforced parts

Effect of phosphate based inhibitor on the threshold chloride to initiate steel corrosion in saturated hydroxide solution

In-situ study of the cracking of metal hydride electrodes by acoustic emission technique

Since the potential of corrosion of any metal in contact with concrete is a function of a large number of variables related to the composition of pore solution, degree of polarisation, temperature and cover depth, no quantitative (corrosion rate) conclusion can be drawn from it. Potentials do not provide relevant information on the amount of corrosion. The validity of these interpretations has been questioned in some situations such as saturated structures, or when carbonation is the cause of the corrosion or cathodic processes are modified. Half cell potential technique (ASTM C 876) is however a useful tool widely used for in situ assessment of the corrosion state of rebars. Some applications of the ASTM C 876 standard are presented and it has been shown that this standard cannot be used under all conditions. Finally, some recommendations are provided in an attempt to optimise the application of the ASTM C 876 standard.

Influence of environmental parameters on application of standard ASTM C876-91 : half cell potential measurements

The tenacious oxide passive film, which is formed on the surface of embedded reinforcing steel under high alkaline condition of concrete, protects the steel against corrosion However, the condition of passivity may be destroyed, due to processes such as leaking out of fluids from concrete, atmospheric carbonation or through the uptake of chloride ions Passive steel reinforcing corrosion induced by chloride is a well-known problem, especially where chloride-containing admixtures or chloride contaminated aggregate are incorporated into the concrete The objective of this work is on one hand to study the effect of chloride ions on passivity breakdown of steel, respectively, in simulated concrete pore solution (SCP) and in concrete reinforcement, and on the other hand to reproduce the carbonation phenomena by applying to the concrete samples a heating-cooling cycles In this context, the acoustic emission coupled to the electrochemical techniques (potentiodynamic and electrochemical impedance spectroscopy (EIS)) are used The results show clearly that [Cl-]/[OH-] ratio of 06 is the critical threshold where the depassivation set-up can be initiated In addition, the carbonation process is very aggressive with chloride ions and shows a perfect correlation with acoustic emission evolution A physical model of the reinforcement/electrolyte interface is proposed to describe the behavior of the reinforcement against corrosion in chloride solution (A) "Reprinted with permission from Elsevier"

Detection and identification of concrete cracking during corrosion of reinforced concrete by acoustic emission coupled to the electrochemical techniques

G. Debicki

Papers

Detection and identification of concrete cracking during corrosion of reinforced concrete by acoustic emission coupled to the electrochemical techniques