Mitra Akhtari Zavareh

By Mitra Akhtari-Zavareh and Ahmed Aly Diaa Mohammed Sarhan

In petroleum and petrochemical industries, offshore and onshore systems have to function in an aggressive environment that exposes the production equipment components to thermal cycling and wear and corrosion. Although maintenance of material degradation in oil and gas is costly, internal and external parts of the equipment and pipelines must be well inspected and continually maintained. For this reason, highly advanced corrosion and wear–monitoring systems must be installed in the critical areas of the plant to protect pipes and equipment from seawater and crude oil. Therefore, researchers are in search of advanced materials and methods that could be applied in oil and gas pipelines and accessories for increasing their working time. The common manufacturing processing method for improving the surface of piping and accessories is overlay welding or cladding. This method has some limitations, such as its limitation for choosing materials. In addition, the high temperature of welding causes some defects on the final surface, such as thermal residual stress, cracking, and distortion in the substrate. The method is also time consuming and costly. However, the coating method provides a blend of unique properties with low cost. Thermal spray methods are cold spraying techniques that have a considerably less thermal stress, residual stress, and other defects. Among different thermal spray coating techniques, high-velocity oxygen fuel (HVOF) and plasma are the most commonly used thermal spraying coating processes to produce anti-wear and corrosion coatings with different types of materials such as metal, alloys, and ceramic composite . Furthermore, HVOF and plasma thermally sprayed coating processes induce microstructure heterogeneities, which increase the corrosion and wear resistance. In this research, one type of alloy with chemical composition NiCrCoAlY was chosen for increasing corrosion resistivity of carbon steel piping. A corrosion behavior of coated samples in seawater was investigated for 30 days. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results indicated that these types of alloys protected the surface of carbon steel piping from harsh environments. However, the corrosion protection of NiCoCrAlY deposited by HVOF technique is higher than a plasma coating technique.

Part of the book: Advances in Tribology