According to the service temperature, it can be divided into low-temperature anticorrosive coatings, normal-temperature anticorrosive coatings and high-temperature anticorrosive coatings. Surface treatment: roughen the machine surface with sand blasting or angle grinder to remove dust, oil stain and moisture on the base surface, so that fresh base material is exposed on the surface;
Priming: Fill the pores, pits and grooves on the construction surface with anticorrosive glue, and then paint BD4 17 anticorrosive coating glue as primer;
Scale adhesive coating: BD4 18 scale anticorrosive coating adhesive can be coated on the primer after the initial setting, and it is suitable for one-way scraping coating; After the first layer of scale coating glue is initially cured, the next layer can be coated;
Surface coating: BD4 17 anticorrosive coating adhesive can be used as the surface layer after the initial setting of the last layer of scale coating adhesive.
Maintenance: The prepared anticorrosive coatings should be maintained for 24 hours before being put into use. When the temperature is lower than 5℃, it is necessary to heat or extend the curing time. Graphite is hexagonal carbon, in the form of leaflike scales and dense blocks. It has metallic luster and can be divided into natural graphite and artificial graphite according to its source. Flake graphite is a natural solid lubricant with layered structure, which is rich in resources and low in price. Graphite flake has the characteristics of complete crystallization, thin and good toughness, excellent physical and chemical properties, good electrical conductivity, good thermal shock resistance and corrosion resistance. According to the carbon content, flake graphite can be divided into high carbon graphite (carbon content is more than 99.9%), medium carbon graphite (carbon content is 80%-93%) and low carbon graphite (carbon content is 50%-75%). Flake graphite is widely used in refractories in metallurgical industry, pencil lead in light industry, electrodes in battery technology, lubricating and sealing materials in chemical industry, etc. As a functional filler of coatings, it is mainly used in anticorrosive coatings, fireproof coatings and conductive coatings.
As an anticorrosive material, it is an antirust primer made of carbon black, talcum powder and oil, which has good chemical resistance and solvent corrosion resistance; If chemical pigments such as zinc yellow are added to the formula, the antirust effect will be better.
Expandable graphite is used as fire-retardant filler, which is a graphite interlayer compound obtained by chemical or electrochemical treatment with natural graphite flake as raw material. Under the heating condition, the volume of expandable graphite expands rapidly (up to 300 times) to suffocate the flame, and at the same time, it produces expandable substances, which can isolate the flame and delay or interrupt the spread of the flame. Moreover, it is nonflammable and has good flexibility, high surface energy and good strength of carbonized layer. However, the volume and dosage of the swelling body should be properly selected. The test shows that the particle size is 150 μm, the expansion rate is 30%, and the dosage is 5%.
Flake graphite can be directly used as carbon conductive filler or made into composite conductive filler for conductive coatings. However, due to a large number of graphite flakes, the performance of the coating will become brittle and its application will be limited. Therefore, measures are taken to further improve the conductivity of graphite and effectively reduce the addition of graphite scales. Domestic Tianhua Chemical Machinery Research Institute has developed a high volume strength and good wear resistance with large flake graphite with high electrostatic conductivity as the main aggregate and high temperature resistant and corrosion resistant resin as the matrix.
Solvent-free thick film conductive coating takes chopped fiber material with good deformation resistance and cracking resistance as functional filler. The coating has the characteristics of corrosion resistance, low curing residual stress, good resistance to matrix deformation and cracking, stable construction performance and long-term static conduction. It can be used to guide the electrostatic coating of the inner wall of crude oil storage tank. The data show that the composite conductive filler is prepared by coating copper, nickel, silver and other metals on graphite powder by electroless plating technology, and it is used in conductive coatings with 30% dosage, which not only has good conductivity, but also further improves corrosion resistance.