Products > High Precision Balls > Silicon Nitride

Balls: Silicon Nitride
Material	Size Range	Grade
Silicon Nitride	1/32 - 2" (.0312mm - 50.8mm)	3-24
Larger sizes available upon special order.

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)	2.3	3.4
Resistivity, Ohm-m	1010	1016
Compressive Strength Mpa (ksi)	3000 (435)
ASpecial material data should be obtained from individual suppliers.