Valve's corrosion, was usually understood that for the valve metallic material the destruction which receives in chemistry or under the electrochemistry environment function. Because “the corrosion” the phenomenon appears middle the metal and the environment spontaneous interaction, therefore, how isolates the metal and the environment or the more use nonmetallic composition material, then becomes the people ordinary matter of concern.

It is well known, the metal corrosion destroys to valve's function deadline, the reliability and the service life has the quite tremendous influence. The machinery and the corrosion agent increased the faying surface total wearing capacity greatly to the metal function. Valve in operating process, friction superficial total wearing capacity. Valve in operating process, friction surface, because the simultaneous mechanical effect and the metal and the environment carry on chemistry or the electrochemistry interaction result have the attrition and the destruction. Speaking of the valve, its pipeline work climatic conditions complex; Medium and so on petroleum, natural gas and oil layer water the hydrogen sulfide, the carbon dioxide and certain organic acid's appearance causes its metal surface the destructive power to increase, thus loses the working ability rapidly.　

The time which and the metal because the metal chemical etching is decided in the temperature, in the friction components' mechanical load, the lubricant contains the sulfide which and the acid-proof stability and the medium contact continues to nitrides the process the catalytic effect, the corrosion erosion material member to metal conversion rate and so on. Therefore, the metal valve's anticorrosion method (or measure) and the composition material valve's application, then becomes one of present valve profession research subjects.

First, the metal valve's anticorrosion, may understand that for the spreading protects it on the metal valve not the condition protector which corrodes (for example paint, pigment, lubricant and so on), causes the valve, regardless in the manufacture, the preservation, the transportation is not corroded in its use's complete process.　

The metal valve anticorrosion's method decided that in the demand protection deadline, the transportation and the preserved condition, the valve construction feather and the material, certainly, the adaptation considered relieves the anticorrosion the economic effect.　

The metal valve and the spare part anticorrosion's method mainly has 4 kinds:
1st, will volatilize easily the corrosion inhibitor puts in the steam in the atmosphere (with inhibition paper package, moves suppresses air to pass product cavity room and so on).
2nd, use by inhibition Shui He spirit of ethyl-nitrite.
3rd, will guard against corrosion (protection) the material thin layer to spread in the valve and the spare part surface.
4th, will spread by the inhibition thin film or the polymer thin layer in the valve and the spare part surface. (note: The present valve Production enterprise, widely dissolves the class using the lubricant and the water inhibition to guard against corrosion. )

Second, the material valve's application composition material valve, surpasses the metal valve in many corrosive operating mode, first is the corrosion resistivity, next is the net weight, as for its intensity, must be decided by the enhancement textile fiber shape, the arrangement and quantity. (, the textile fiber percentage is generally speaking bigger, composition material's intensity is bigger. ) in the valve application, the textile fiber weight content basic scope is 30%-40%, but its chemical stability mainly by fills in the final product seals the textile fiber the resin main body characteristic decision. In the composition material valve, its solid state polymer main body already may be the thermoplastic (for example PVC- gathers leaning vinyl fluoride, PPS- to gather diphenyl sulfide and so on), may also be the thermosetting resin (for example polyester, ethylene its and epoxy resin and so on). The thermosetting resin in lies between under the warm condition maintains its intensity the performance surpasses the thermoplastic, (i.e. thermosetting resin has high thermal deformation temperature). (note: In the use operating mode, composition material's heat-resistance's determination is called the thermal deformation temperature. )　

The graphite fibre which at present, the chemical flow valve most commonly used composition material for the ethenyl epoxy resin (hot plastic material), its enhancement textile fiber to cut to pieces the glass fiber which (1/4 inch long) and cuts to pieces (1/4 inch long). As soon as the next table most widespread use's composition material's performance and the anti-corrosive metal's performance does compares. Glass enlargement mode ethen yl graphite enlargement mode ethenyl graphite enlargement mode PPS 316SS Hast-C longitudinal strength (Psi) 4000 6000 26000 85000 90000 bending strength (Psi) 8000 12000 35000 NA NA compressive strength (Psi) 14000 18000 21000 85000 90000 thermal deformation temperatures (°F) 295 7320 520 NA NA thermal-expansion coefficient (in/in/°F) 15×10-6 15×10-6 13×10-6 6.3×10-6 9.9×10-6

Note: NA namely not suitable (or invalid) from the superficial analysis, the glass and the graphite enhancement composition material and the metal compares, its tensile strength is low, therefore, the composition material valve should have the stress big spot the thick section and attaches the stiffener to achieve with the metal same performance.　

As a result of composition material valve's anti-corrosive performance, high strength and weight quantity, causes it to become in many metals or in the absafil plastic piping system corrosive operating mode, economical may choose the valve product. In the chemical flow operating mode, the composition material valve's use prospect is extremely good. In the valve industry, the organic material and composition material's use, already was not in the tradition the metal and the nonmetallic valve material concept. The ceramics (may from 400℃ enhance valve's application temperature to 1200℃ above), the plastic (have rust prevention anticorrosion characteristic), the composition material (to have, weight to be light anti-corrosive, intensity high characteristic), the memory alloy (valve which makes using shape memory alloy or temperature memory alloy's invertibility and high elasticity) and so on. The new material, is developing has the high performance valve new product in large numbers. The new technology's development, causes each kind of engineerig material to apply in the valve manufacture already becomes possibly.