Microstructural Characterization and Corrosion-Resistance of Borided Rebar

Abstract

The serviceability and ultimate strength of concrete elements within reinforced structures are affected negatively due to corrosion of steel bars. In the present paper, investigations were carried out to study the corrosion behavior of protected low carbon ribbed reinforcing steel with boron in concrete. The ribbed steel bars were in size of Ø12 and Ø14, and they were coated with boron. The coating process was carried out at 800, 900 and 1000 oC for 2 h and 4 h, respectively. Depending on the boriding parameter the boride layer thickness on the surface of borided rebars ranged from 32.58 μm and 213.74 μm. After boriding, the rebars were embedded into the concrete and exposed to rapid corrosion test. The results show that the corrosion rate and cross section loss of protected steel bars decreases when compared to unprotected rebars. Corrosion beginning time of borided rebars delayed about 2 times when compared to plain rebar. Boride layers reduced the corrosion rate of the reinforcements by 2.39 to 10.65 times and the section losses of the reinforcements by 2.54 to 4.72 times depending on the boriding temperature and duration.

Effects of Cr Concentration on the Morphology and Corrosion Resistance of Ni-Cr Coatings Prepared by the Electrodeposition Process on 25CrMo4 Steel

“…On the other hand, the good resistance of the 0.2 wt.% Cr coating to 3.5 wt.% NaCl may be explained by the excellent adhesion of the Ni-Cr layer towards the surface electroplated [33]. Corrosion is well known to be related to adherence [36].…”