High Wear Proof Silicon Nitride Ceramic Zirconia , Casting Refractory Tube

Refractory Casting High Wear Resistance Black Silicon Nitride Zirconia Ceramic Tube c610 c799 Alumina Ceramic

Product Description

Advantages

Silicon nitride ceramic is a kind of superhard material, which has lubricity and wear resistance. It does not react with other inorganic acids except hydrofluoric acid (reaction equation: Si3N4+4HF+9H2O=====3H2SiO3 ( Precipitation) +4NH4F), strong anti-corrosion ability, anti-oxidation at high temperature. Moreover, it can withstand cold and hot shock, and is heated to above 1 000℃ in air, and is rapidly cooled and heated rapidly without breaking. Because of the excellent characteristics of silicon nitride ceramics, it is often used to manufacture mechanical components such as bearings, gas turbine blades, mechanical seal rings, and permanent molds. If a silicon nitride ceramic that is resistant to high temperatures and does not easily transfer heat is used to manufacture the heating surface of the engine component, not only the quality of the diesel engine can be improved, fuel is saved, but also thermal efficiency can be improved. The silicon nitride ceramic can be used as a gas turbine combustion chamber, a silicon nitride mechanical seal ring (silicon nitride ring), an electromagnetic pump pipe (silicon nitride tube) for conveying aluminum liquid, a valve, a permanent mold, a molten steel separation ring, and the like. Si3N4 ceramic is a covalent bond compound. The basic concatenation is located in the tetrahedron. The four vertices are [SiN4] tetrahedrons. The silicon atoms are located in the center of the tetrahedron. There are four nitrogen atoms around them, and then Each of the three tetrahedrons shares the form of one atom, forming a continuous and robust network structure in three dimensions. Many of the properties of silicon nitride are attributed to this structure. Pure Si3N4 is 3119, with both α and β crystal structures, all of which are hexagonal crystals. The decomposition temperature is 1800℃in air and 1850℃ in 011 MPa nitrogen. Si3N4 has a low thermal expansion coefficient and a high thermal conductivity, so its thermal shock resistance is excellent. The hot-pressed sintered silicon nitride is heated to l000℃ and then put into cold water without cracking. At less high temperatures, Si3N4 has higher strength and impact resistance, but it will break with the increase of use time above 1200℃, which will reduce the strength and fatigue damage at 1450℃, so Si3N4 The use temperature generally does not exceed 1300 ° C. Due to the low theoretical density of Si3N4, it is much lighter than steel and engineering superalloy steel. Therefore, it is suitable to replace the alloy steel with Si3N4 ceramic in places where high strength, low density and high temperature resistance are required It is.

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