Corrosion Resistance Mechanism of Mica–Graphene/Epoxy Composite Coating in CO2-Cl− System

Abstract

The working environment for tubing in oil and gas fields is becoming more and more serious due to the exploration of unconventional oil and gas resources, leading to the increasing need for a protective internal coating to be used in tubing. Therefore, a new mica–graphene/epoxy composite coating with different graphene contents (0.0, 0.2, 0.5, 0.7, and 1.0 wt.%) was prepared to improve the tubing resistance to a corrosive medium, an autoclave was used to simulate the working environment, and an electrochemical workstation assisted by three-electrodes was used to study the electrochemical characteristics of the coating. The results showed that the addition of a certain amount of graphene into the mica/epoxy coating significantly improved the corrosion resistance of the composite coating, and when the graphene content increased, the corrosion resistance of the mica/epoxy coating first increased and then decreased when the corrosion current density of a 35 wt.% 800# mica/epoxy coating with a 0.7 wt.% graphene content was the lowest (7.11 × 10−13 A·cm−2), the corrosion potential was the highest (292 mV), the polarization resistance was the largest (3.463 × 109 Ω·cm2), and the corrosion resistance was improved by 89.3% compared to the coating without graphene. Furthermore, the adhesion of the coating with 0.7 wt.% graphene was also the largest (8.81 MPa, increased by 3.4%) and had the smallest diffusion coefficient (1.566 × 107 cm2·s−1, decreased by 76.1%), and the thermal stability improved by 18.6%. Finally, the corrosion resistance mechanism of the composite coating with different graphene contents at different soaking times was revealed based on the electrochemistry and morphology characteristics other than water absorption and contact angle.

Preparation and corrosion resistance study of two‐dimensional mica‐based composite coatings modified with UIO‐66 and polyethyleneimine

“…The adhesion value can measure the mechanical strength and waterproof ability of the coating. 40 In Figure 10, the pure EP coating has the lowest adhesion.…”

A Method of Managing Waste Oak Flour as a Biocomponent for Obtaining Composites Based on Modified Soybean Oil

“…Generally, among the fillers intended for the strengthening of epoxy resins, one can distinguish between inorganic, organic, synthetic, and natural fillers. The most popular inorganic fillers include chalk [ 27 , 28 ], kaolin [ 29 ], silica [ 30 , 31 ], mica [ 32 , 33 ], quartz, various types of metal oxides, and metallic powders [ 34 ]. These fillers are most often in powder form; the main advantages of their application in polymeric composites are a reduction in the cost of the finished product, improvements in thermal stability, and reductions in processing shrinkage [ 35 ].…”