▎ 摘　　要

NOVELTY - Coating comprises an inner layer comprising 10-16 pts. wt. polytetrafluoroethylene resin, 5-7 pts. wt. first filler, 8-12 pts. wt. boron phenolic resin, 3-4 pts. wt. methyl methacrylate, 50-56 pts. wt. first solvent, and 4-7 pts. wt. curing agent, and an outer layer comprising 15-20 pts. wt. metronidazole-modified graphene oxide composite material, 7-11 pts. wt. polyimide resin, 3-5 pts. wt. alpha -amino- alpha -iminophosphonic acid inner salt, 1-2 pts. wt. hydrophobically modified magnetic particles, 6-9 pts. wt. second curing agent, 5-10 pts. wt. second filler, and 32-36 pts. wt. second solvent. The thickness ratio of inner layer to outer layer is 1:3.2-3.6. USE - Coating used for protecting oil casings, drill pipes and oil pipes in oil field exploitation. ADVANTAGE - The coating has high anti-scaling rate, good anti-corrosion performance and anti-wax effect. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing coating, which involves: (A) uniformly mixing all the raw material components of the inner layer, raising the temperature to 180-190 degrees C at a heating rate of 1-2 degrees C/minute under continuous stirring, and maintaining it for 40-60 minutes; (B) spraying on the surface of treated equipment to be protected by spraying equipment, solidifying and then cooling to room temperature to form an inner layer; (C) mixing the metronidazole-modified graphene oxide composite material, the polyimide resin and the second solvent in the outer raw material component uniformly under continuous stirring conditions, and increasing the temperature to 100-128 degrees C at a heating rate of 1.2-1.5 degrees C/minute, and maintaining the temperature for 10-20 minutes; and (D) adding other remaining raw material components, raising the temperature to 175-180 degrees C at a heating rate of 0.8-1 degrees C/minute, maintaining temperature for 2-3 hours, and spraying on the inner surface of the treated equipment to be protected by spraying equipment, solidifying and cooling to room temperature to form an outer layer, and obtaining desired product.