Silicon Nitride Ceramic Balls

 

Silicon Nitride:      Grade Size Range in Inches and Millimeters 3 - 5 1/32 - 2                               0.793 - 50.800

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Silicon Nitride Specified for use in such high-technology industries such as hybrid bearings, aerospace and defense; Silicon Nitride ceramic balls feature these advanced characteristics: Excellent corrosion resistance withstands attack from harsh chemicals and demanding environmental conditions. Lightweight Silicon Nitride weighs 60% less than steel which reduces centrifugal force, skidding and wear under high speed and acceleration. Superior Surface Finish, Ra 0.1 7-0.25 micro inches may extend L-10 life to as much as 10 times that of steel bearings. High Temperature Hardness is twice that of steel. These all-ceramic balls retain their strength and hardness up to 1800 degrees F. Silicon Nitride is further characterized by its low density of 3.2 g/cc, high flexural strength of 1.0 GPa, and fracture toughness of 6 MPa/M2. These outstanding properties, together with Hoover's exacting manufacturing standards regarding sphericity, diameter tolerance, and surface finish, make Hoover's silicon nitride balls ideal for high performance ball bearings.

Material Analysis Grade Allowable Lot Diameter Variation Basic Diameter Tolerance Allowable Ball Gage Deviation High Allowable Ball Gage Deviation Low Max. Surface Roughness.  Arithmetical Average. Micro-meters (Micro-inches) 2C 0.08 (3) ±0.51 (±20) +0.51 (+20) -0.51 (-20) 0.004 (0.15) 3C 0.13 (5) ±0.51 (±20) +0.51 (+20) -0.51 (-20) 0.004 (0.15) 5C 0.25 (10) ±0.76 (±30) +0.76 (+30) -0.76 (-30) 0.005 (0.20) 10C 0.51 (10) ±2.54 (±100) +1.27 (+50) -1.02 (-40) 0.006 (0.25) 16C 0.80 (32) ±2.54 (±100) +1.27 (+50) -1.02 (-40) 0.009 (0.35) 24C 1.22 (48) ±2.54 (±100) +2.54 (+100) -2.54 (-100) 0.013 (0.50) 48C 2.44 (96) N/A N/A N/A 0.013 (0.50)

Mechanical Properties   Minimum Maximum Density, g/cc (lb/ft3)........................................................................... 3.0 (187) 3.4 (212) Elastic Modulus, Gpa (ksi).................................................................. 270 (39150) 330 (47850) Poisson’s ration................................................................................. 0.23 0.29 Thermal Conductivity, W/m-ºK (Btu/h-ft-ºF) - @ 20ºC (Room Temp.)......... 20 (11.5) 38 (21.9) Specific Heat, J/kg-ºK (Btu/1bm-ºF)..................................................... 650 (0.167) 800 (0.191) Coefficient of thermal expansion, x10-6/ºC (Room Temp. to 500ºC)......... 2.8 4.0 Resistivity, Ohm-m............................................................................. 1010 1016 Compresive Strenght, Mpa (ksi)........................................................... 3000 (435)   ASpecial material data should be obtained from individual suppliers.

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