(1) Metal Material

In some mechanical seals, due to the good processing properties of the metal, the metal material is often used as the material of the sealing surface. Under normal circumstances the use of the alloy to manufacture seal, such as nickel alloys (nickel-iron alloy), tungsten carbide (cobalt, chromium and titanium alloy) and the like; for some impatience corrosion, such as cast iron, tool steel and bearing steel and other special steel used in the low load, oily liquids.

Now the main mechanical seals ring materials are hard carbide (YG6), SiC, aluminum oxide, etc., as well as in marine mechanical seal in carbonation Peng harder materials.

(2) Engineering ceramics (alumina)

Alumina high hardness, wear resistance, but low thermal shock resistance. Add a small amount of alumina into aluminum metal element cermet. Its composition is 88-92% AL2O3, the balance being Fe, Cr, Ni and other metal elements. Adding metal elements can improve the thermal conductivity of the alumina cermet and reduce brittleness, but the corrosion resistance decreased. The ceramic used in quantities larger car cooling water pump mechanical seal. Since the industrial ceramics used in the mechanical seal, continue to be a high-performance alternative to silicon carbide, and only the best corrosion resistance, 99.5% alumina has a certain amount of use in the petrochemical industry.

(3) Hard metal (tungsten carbide)

Sintered tungsten carbide particles of a hard ductile metal (Co, Ni) Binder sintering. Typically used for heavy-duty (high PV) applications. Although its price is more expensive, however, because it toughness and rigidity, good wear resistance and more and more used in mechanical seal. 6% cobalt WC most widely used; nickel based WC corrosion due more to better use in the petrochemical industry, but its overall performance is worse than the cobalt-based tungsten carbide, but its corrosion resistance than the cobalt-based WC better.

(4) New ceramic (silicon nitride)

With respect to silicon carbide, silicon nitride, hardness and corrosion resistance somewhat lacking, but the main thing is the material brittle, in the processing and installation easily damaged, so the mechanical seal is seldom used.

Silicon carbide's hardness close to diamond and has outstanding abrasion resistance. Silicon carbide mechanical seals, one of the most widely used material, silicon carbide except at high temperature molten alkali and strong oxidizing gas, but in the whole concentration of sulfuric acid and caustic close boiling can also be stably used, especially in over a wide temperature range to maintain corrosion resistance and abrasion resistance.