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Silicon Nitride: Available Grades and Sizes
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Grade
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Size Range in Inches
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3 - 24
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1/32 - 2
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Larger sizes available upon special order.
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Silicon Nitride Download Product Sheet
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.
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Material Analysis
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Grade
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Allowable Lot Diameter Variation
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Basic Diameter Tolerance
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Allowable Ball Gage Deviation High
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Allowable Ball Gage Deviation Low
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Max. Surface Roughness. Arithmetical Average. Micro-meters (Micro-inches)
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2C
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0.08 (3)
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±0.51 (±20)
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+0.51 (+20)
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-0.51 (-20)
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0.004 (0.15)
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3C
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0.13 (5)
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±0.51 (±20)
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+0.51 (+20)
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-0.51 (-20)
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0.004 (0.15)
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5C
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0.25 (10)
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±0.76 (±30)
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+0.76 (+30)
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-0.76 (-30)
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0.005 (0.20)
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10C
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0.51 (10)
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±2.54 (±100)
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+1.27 (+50)
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-1.02 (-40)
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0.006 (0.25)
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16C
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0.80 (32)
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±2.54 (±100)
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+1.27 (+50)
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-1.02 (-40)
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0.009 (0.35)
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24C
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1.22 (48)
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±2.54 (±100)
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+2.54 (+100)
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-2.54 (-100)
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0.013 (0.50)
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48C
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2.44 (96)
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N/A
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N/A
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N/A
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0.013 (0.50)
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Mechanical Properties:
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Minimum
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Maximum
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Density, g/cc (lb/ft3)............................................................................
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3.0 (187)
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3.4 (212)
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Elastic Modulus, Gpa (ksi)...................................................................
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270 (39150)
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330 (47850)
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Poisson’s ration..................................................................................
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0.23
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0.29
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Thermal Conductivity, W/m-ºK (Btu/h-ft-ºF) - @ 20ºC (Room Temp.)..........
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20 (11.5)
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38 (21.9)
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Specific Heat, J/kg-ºK (Btu/1bm-ºF)......................................................
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650 (0.167)
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800 (0.191)
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Coefficient of thermal expansion, x10-6/ºC (Room Temp. to 500ºC)..........
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2.8
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4.0
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Resistivity, Ohm-m..............................................................................
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1010
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1016
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Compressive Strength Mpa (ksi)...........................................................
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3000 (435)
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ASpecial material data should be obtained from individual suppliers.
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