WC-Co and WC-Co-Cr Coatings for the Protection of API Pipeline Steel from Corrosion in 4% NaCl Solution

Abstract

Two inorganic coatings, namely 88%WC-12%Co (PSC1) and 86%WC-10%Co-4%Cr (PSC2), were deposited on the surface of an API-2H pipeline steel using high velocity oxy-fuel deposition. The corrosion of the uncoated and coated API-2H steel after their immersion in a solution of 4.0% NaCl for 1 h, 24 h, and 48 h has been studied. Various electrochemical measurements such cyclic potentiodynamic polarization, electrochemical impedance spectroscopy, and potentiostatic current versus time were employed. The surface morphology and analysis were carried out via the use of scanning electron microscopy and energy dispersive X-ray examinations. All experiments have revealed that the deposited coatings decreased the cathodic current, anodic current, corrosion current density (jCorr), absolute current versus time, and the corrosion rate (RCorr) compared to the uncoated API-2H steel. The value of jCorr decreased from 47 µA/cm2 for uncoated steel to 38 µA/cm2 for the PSC1-coated steel and 29 µA/cm2 for the PSC2-coated steel. Moreover, prolonging the time of exposure decreases the jCorr and RCorr values. The jCorr values obtained after 48 h recorded 32, 26, and 20 µA/cm2 for the uncoated, PSC1, and PSC2 samples, respectively. Moreover, applying these coatings also led to increasing the corrosion resistance (RP) after all the exposure periods of time. In addition, the PSC2 coating was found to be more protective against corrosion for the surface of the steel than the PSC1 coating.

Geometric Influence of Hard Phase on Corrosion Performance between WC-Reinforced Coatings Prepared by High-Velocity Oxygen-Fuel Spray and Electric Contact Strengthening

“…In the reverse scan curve, all of the coatings showed a negative hysteresis loop at first, followed by positive hysteresis. The areas of the negative hysteresis loops belonging to the E1 and E2 coatings were larger than those of the H1 and H2 coatings, indicating more serious pitting corrosion [25,26]. This is associated with the spherical geometry of WC and corresponds to the coating surface morphology after corrosion, as shown in Figure 10.…”

Flexural and corrosion behaviour of WC-10Co-4Cr + Graphene sprayed on textured HSLA-steel

“…One such cermet is WC-10Co-4Cr; this coating was asserted to have better mechanical and corrosion performances than that of other cermet coatings. Sherif et al, used high velocity oxy-fuel (HVOF) coating deposition technique to deposit WC12Co and WC-10Co-4Cr coatings on API-2H pipeline steel, and corrosion tests were conducted on both bare and coated steel substrate by immersing it in 4% NaCl solution for 1, 24, and 48 h [15]. The author concluded that WC-10Co-4Cr cermet coating has provided better corrosion resistance compared to the resistance offered by WC-12Co coating.…”

Corrosion and Wear Behavior of WC–10Co4Cr Coating under Saturated Salt Drilling Fluid

“…Generally, they not only have to transfer huge bit weights and withstand great torsional stress, but they also suffer from erosion, corrosion, and wear during the work process [ 4 , 5 , 6 ]. Drilling fluid could cause the significant erosion and corrosion of a drill pipe, especially saturated saltwater, which is usually applied as drilling fluid in permafrost and salt rock drilling [ 1 , 7 , 8 , 9 , 10 , 11 ]. Moreover, the diameter of the pipe joint is usually larger than that of the drill pipe, resulting in significant wear.…”

“…Coating on the surface with excellent wear resistance and good protective effects is considered one of the most effective methods to improve the service performance of components in fields such as agricultural machinery, energy, transportation, chemical industry, and drilling engineering. Hence, a hard coating could be applied to the surface of the drill pipe or joint to improve its anti-corrosion and anti-wear [ 8 , 13 , 14 , 15 , 16 ]. There are several major coating methods to prepare hard coatings, such as high-velocity oxygen–fuel spraying [ 1 , 17 ], cold spraying [ 15 , 18 ], plasma spraying [ 19 ], micro-arc oxidation [ 20 , 21 ], high-speed laser cladding [ 22 ], high-power impulse magnetron sputtering [ 16 ], plasma electrolytic oxidation [ 23 ], and so on [ 13 , 24 ].…”

“…There are several major coating methods to prepare hard coatings, such as high-velocity oxygen–fuel spraying [ 1 , 17 ], cold spraying [ 15 , 18 ], plasma spraying [ 19 ], micro-arc oxidation [ 20 , 21 ], high-speed laser cladding [ 22 ], high-power impulse magnetron sputtering [ 16 ], plasma electrolytic oxidation [ 23 ], and so on [ 13 , 24 ]. WC-based cemented carbide possesses high hardness, outstanding strength, and excellent toughness, so is widely used as anti-wear material [ 1 , 8 , 17 ]. WC-based coatings are often coated on the surface of the pipe to increase its wear and corrosion resistance.…”