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Si3N4 ceramic powder

Shanghai Gaoyue Ceramics Co. Ltd.

Si3N4 ceramic powder

Country/Region China
Categories Other Ceramic Fiber Products

Product Details

Si3N4 ceramic powder > Si3N4 ceramic powder

Si3N4 ceramic powder

  • Product Description
1.Applications
Silicon nitride has an excellent combination of strength, hardness, toughness, corrosion resistance, high temperature capability, and low weight that make it useful for many applications involving high contact stress sliding or rolling contact, corrosive chemicals, or high temperatures.
In bearing technology, silicon nitride finds increasing use as balls and rolls in so-called hybrid bearings. Only silicon nitride materials proved to be suitable because in case of damage, they behave comparably to metals by the incidence of pittings and not by complete failure. In such a case, friction is increased and noise evolves; however, the bearing remains functional.
The advantages of silicon nitride as bearing ball materials and the applications

Properties

Application

  1. Lowweight
  2. Wearresistance
  3. Corrosionresistance
  4. HighYoung’s modulus
  5. Electricalinsulation
  6. Non-magnetism
  7. Temperatureresistance
  8. Highthermal shock resistance
  9. Highoxidation resistance
  1. Toolspindle bearings
  2. Turbomolecular pump
  3. Dentistturbines
  4. Vacuumtechnology
  5. Foodindustry
  6. Aerialbearings
  7. Skatingand bicycle bearings
Specific advantages in comparison with steel bearings can be given as follows for the example of a spindle bearing in a grinding machine.
Essentially increased lifetime
Higher stiffness, lower vibration
High revolution also with grease lubrication
Good emergency behavior
Low temperature evolution during use due to low friction
Cost effective lubrication, in the case of sealing also for the entire lifetime
These advantages of hybrid bearings mainly result from lower friction due to the higher surface smoothness as well as the smaller Hertzian contact ellipsis of the silicon nitride balls with the raceway. In combination with the lowered adhesion between silicon nitride and the steel, lower requirements for the lubrication also result. Grease lubrication, deficient lubrication or even dry-running conditions can be sufficient for hybrid bearings.
Other applications of the hybrid bearings:
1)In electrically driven vehicles because of the high electrical resistance of silicon nitride. There is no need for further insulation.
2)Another very prominent application is their use in the fuel pumps of the space shuttle main engine, operating at the temperature of liquid oxygen or hydrogen, no lubrication is feasible under such condition.
3)In food industry or in highly corrosive environment, such as pumps and devices for the chemical industry.
4)In carriers through Zn-melts to coat metallic parts and sheets.
2. Categories of bearing ball ceramic materials produced in Shanghai Gaoyue Ceramics Co.Ltd
Hiped, GPS sintered silicon nitride, aluminium oxide, zirconium oxide and silicon carbide bearing balls both polished up to G3 grade or ball blanks.
3.Material properties
(1)Silicon Nitride Bearing Ball Materials of the Company

Properties

CH-30(HIP)

CH-25(GPS)

Density,g/cm3

3.25

3.28

Porosity,%

<0.1

<1

3-point Bending Strength, MPa
(at room temperature)

900

800

Fracture Toughness,MPa×m1/2

6

6

Hardness (Hv10),GPa

15.5

15.5

Young’s Modulus,GPa
(at room temperature)

310

310

Thermal Conductivity,W/m×K
(at room temperature)

25

25

Coefficient of Thermal Expension,
20-1000oC,10-6K-1

3.2

3.2

TheMain Raw Materials

Si3N4,Y2O3,Al2O3,
Ticompound

Si3N4,Y2O3,Al2O3,
Ticompound

(2) The Comparison of Several Ceramic Materials

Si3N4

Al2O3

ZrO2

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