There are several commonly used materials in mechanical seals, such as clean water, river water, seawater, etc. Let's explain them specifically. For clean water: at room temperature; (dynamic) 9CR18, 1CR13 cobalt-chromium-tungsten overlay welding, cast iron; (static) resin-impregnated graphite, bronze, phenolic plastic. For river water (with sediment): at room temperature; (dynamic) tungsten carbide, (static) tungsten carbide. For seawater: at room temperature; (dynamic) tungsten carbide, 1CR13 cobalt-chromium-tungsten overlay welding, cast iron; (static) resin-impregnated graphite, tungsten carbide, metal ceramics. For superheated water at 100 degrees: (dynamic) tungsten carbide, 1CR13 cobalt-chromium-tungsten overlay welding, cast iron; (static) resin-impregnated graphite, tungsten carbide, metal ceramics. For gasoline, lubricating oil, and liquid hydrocarbons: at room temperature; (dynamic) tungsten carbide, 1CR13 cobalt-chromium-tungsten overlay welding, cast iron; (static) resin-impregnated graphite or tin-antimony alloy graphite, phenolic plastic. For gasoline, lubricating oil, and liquid hydrocarbons at 100 degrees: (dynamic) tungsten carbide, 1CR13 cobalt-chromium-tungsten overlay welding; (static) bronze or resin-impregnated graphite. For gasoline, lubricating oil, and liquid hydrocarbons containing particles: (dynamic) tungsten carbide; (static) tungsten carbide. Of course, these are commonly used materials, and there may be different requirements in different situations. There are also some special materials