There are mainly two materials: PTFE and glass fiber PTFE. Used in strong corrosive media with lower temperature and various pressures. There are steel belt-asbestos, steel belt-PTFE, steel belt-flexible graphite, etc.Graphite Gasket Flat gasket made of soft graphite, suitable for high temperature and strong corrosive media. Suitable for valves with higher temperature ptfe coated fiberglass adhesive tapes Manufacturers and pressure.

Metal gaskets include pure iron, very soft steel, stainless steel, aluminum and other materials. Generally used on the sealing surface of concave and convex flanges. There are three main types of metal gaskets: 1. Generally used for concave and convex flange sealing surface. Suitable for higher temperature medium pressure valves. The metal-clad graphite gasket used for high-temperature and high-pressure valves is made of thin metal-coated annular asbestos gaskets. Used in higher temperature medium pressure valves.

PTFE gaskets are generally used for tongue-and-groove sealing surfaces. Spiral wound gaskets are made of corrugated metal tape and sealing material tape mixed and wound. The advantages are good corrosion resistance and thermal stability, good plasticity, and a smaller compression force to ensure sealing. Lens gasket-suitable for lens flange sealing surface.. The tooth form is a bevel tooth-shaped corrugation processed on the sealing surface of the metal flat gasket-suitable for Concave-convex flange sealing surface 3.

The disadvantage is that the strength is low and it is easy to stick to the flange sealing surface. Octagonal and elliptical gaskets-suitable for the sealing surface of trapezoidal groove flanges. Asbestos rubber gaskets include universal asbestos boards and anti-corrosion asbestos boards. 2. Asbestos rubber gasket is suitable for smooth flange sealing surface, concave and convex flange sealing surface and tongue and groove flange sealing surface.

Generally, asbestos boards, acid-resistant asbestos boards, oil-resistant asbestos boards, and metal wire asbestos boards are used. The processing accuracy and surface roughness of the metal gasket sealing surface The requirements are very high and the bolt compression force is very large

Polytetrafluoroethylene coatings are widely used in various industries due to their high chemical stability, wide temperature range, outstanding non-stickiness, good thermal stability, excellent aging resistance and radiation resistance. 2. However, the poor wear resistance of PTFE anti-stick coatings limits its application range to a certain extent.1 Coating formula (see Table 1) .

Test materials and main equipment 1.2 Main equipment Power-increasing electric agitator; 202-1 type electric ptfe coated fiberglass adhesive tape heating constant temperature drying oven; 4-10 type box-type resistance furnace; SS16 type liquid sandblasting machine; W-71 type spray gun. 1.1 Test materials Polytetrafluoroethylene concentrated dispersion SFN-1, Sichuan Chenguang; Tin bronze powder QSn6-6-3, Qishan, Shaanxi; Molybdenum disulfide (analytical grade), Shanghai Chemical Reagent Factory; Chromium trioxide (analytical grade),

Tianjin Chemical Reagent factory; polyphenylene sulfide resin, Zigong, Sichuan; titanate coupling agent NDZ-311, NDZ-311W, Nanjing Shuguang; Foamaster111 defoamer, Levelling620 associative leveling agent, film-forming aid alcohol ester 12 , Henkel, Germany; 7010 defoamer, Jieyang Tianyin; Triethylamine (analytical pure), Tianjin. 

Preparation of modified polytetrafluoroethylene coating Choose polytetrafluoroethylene concentrated dispersion as the base material, add fillers (the fillers are dried through a 600-mesh screen) and additives, the steps are as follows: (1) Weigh the required concentrated PTFE dispersion and stir at high speed; (2) Add the required amount of tin bronze powder, molybdenum dioxide, chromium trioxide, polyphenylene sulfide resin, and stir at high speed.

 Coating preparation and coating performance In this study, polytetrafluoroethylene suspension was used as the main component of the coating, and inorganic coatings such as chromium trioxide, bronze powder, molybdenum disulfide, organic filler polyphenylene sulfide resin and additives were added. The modified polytetrafluoroethylene coating developed in this experiment has excellent wear resistance and can effectively expand the application field of coatings.