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Hexoloy Bearings

Bearings
Chemical Processing
Internal Gear Pumps
Clean room/semiconductor applications
Metering Pumps
Food Processing
Sealless Magnetic Centrifugal Pumps

Hexoloy®SiC - A Superior Bearing Material For the Most Difficult Applications

  • Extreme Hardness and High Strength
  • High Abrasion and Wear Resistance
  • Excellent Corrosion Resistance
  • Superior Thermal Shock Resistance

Saint-Gobain Ceramics offers a family of Hexoloy® sintered alpha silicon carbide grades, providing high performance materials that have proven successful in a wide variety of applications and pump design types including:

  • Gear Pumps
  • Magnetically-driven Pumps
  • Canned Motor Pumps
  • Multi-stage Pumps
  • Vertical Pumps
  • Down Hole Pumps
The advantages of Hexoloy SiC
  • As one of the hardest commercially available materials, it provides wear resistant, long service life.
  • Its universal corrosion resistance offers a bearing material with unlimited application potential.
  • Low friction and high strength characteristics result in superior high PV performance.
  • It has high thermal conductivity for excellent thermal shock resistance.
  • Net shape manufacturing capabilities eliminate costly machining operations.
  • Hexoloy SP's unique spherical pore based lubrication provides the ability to survive marginal operating or upset conditions.

There's a Hexoloy SiC Material for your bearing application

Hexoloy SA Silicon Carbide

Hexoloy SA SiC is a pressureless, sintered form of alpha silicon carbide, with a density greater than 98 percent theoretical. It has a very fine grain structure (less than 10µm) for excellent wear resistance and contains no free silicon, which makes it highly chemically resistant in both oxidizing and reducing environments. These abilities coupled with excellent surface finish characteristics make it ideally suited to product lubricated bearing applications.

 

Hexoloy SA Silicon Carbide micrograph

 

Hexoloy SP Silicon Carbide

Hexoloy SP SiC is a sintered alpha silicon carbide material designed specifically for optimum performance in sliding contact applications such as product lubricated bearings. This material improves upon the exceptional corrosion and erosion resisting properties of Hexoloy SA SiC through the addition of unique spherical pores. These discrete, evenly dispersed pores act as fluid or lubricant reservoirs helping to promote the retention of a fluid film at the interface of sliding component surfaces.

 

Hexoloy SP Silicon Carbide micrograph

 

Noralide® NBD-200 Hot Pressed Silicon Nitride

Noralide® NBD-200 Hot Pressed Silicon Nitride (Si3N4) offers a combination of characteristics that make it an ideal material for bearings as well as for other applications where maximum fracture toughness and flexural strength are required. Hot-pressed for maximum strength and density, Noralide® Si3N4 provides better fracture resistance than other ceramic materials. It can easily be machined in a variety of shapes and worked to close tolerances.

 


Unpolished NBD-200 at 100X
  
Etched NBD-200 at 1000X

 

Design Assistance

Our application engineers can help you with design recommendations that allow for cost-effective Hexoloy SiC bearing solutions for your applications. Please contact us to discuss how Hexoloy SiC can benefit your bearing needs.

 

Wear Resistance

In thrust and journal bearings, wear can occur due to upset conditions, abrasive fluids, shaft deflections and general abuse, ultimately causing a complete failure of the bearing. Hexoloy SiC is an extremely hard and wear resistant material. Maximum tested PV (pressure - velocity) exceeds 1 million psi ft/min.

 

 

Corrosion Resistance

Hexoloy SiC exhibits excellent corrosion resistance over a broad range of pH values. It is chemically inert to strong oxidizers unlike tungsten carbide or reaction bonded silicon carbide. Hexoloy SiC outperforms tungsten carbide and aluminum oxide in all chemical categories.

 

 

Mechanical and Physical Properties

Hexoloy SiC offers the optimal combination of mechanical and physical properties. The high strength and modulus of elasticity are complemented by low coefficient of thermal expansion and high thermal conductivity. This combination of properties allows the designer to build rigid, high load bearings while maintaining design clearances across a wide range of operating temperatures.

 

Material Properties - Typical Values
Property
Units
Hexoloy SA SiC
Hexoloy SP SiC
Hexoloy Enhanced® SA
Noralide®
NBD-200 Si3N4
Composition*
-
SiC
SiC
SSiC
Si·N
Grain Size
µm
4-10
4-10
4-10
<2
Density
g/cm3
3.10
3.04
3.13
3.18
Hardness(Knoop 0.1kg load)
kg/mm2
2800
2800
2800
N/A
Hardness(Vickers 10kg load)
GPa
N/A
N/A
N/A
16
Flexural Strength
4pt @ RT**
MPa
x103 lb/in2
380
55
240
35
428
62
800
-
Compressive
Strength @ RT
MPa
x103 lb/in2
3900
560
N/A
3900
560
3500
-
Modulus of
Elasticity @RT
GPa
x106 lb/in2
410
59
400
58
410
59
320
-
Weibull Modulus
(2 parameters)
 
8
19
12
N/A
Poisson Ratio
 
0.14
0.14
0.14
N/A
Fracture Toughness @RT
Double Torsion & SENB
MPa x m1/2
x103 lb/in2 x in1/2
4.60
4.20
4.3
3.9
4.60
4.20
-
-
Fracture Toughness @ RT Indentation
MPa x m1/2
-
-
-
4.1
Coefficient of Thermal Expansion
RT to 700°C
x10-6 mm/mmK
x10-6 in/in °F
4.02
2.20
4.2
2.3
4.02
2.20
2.9***
-
Max. Service Temp. Air
°C
°F
1900
3450
1900
3450
1900
3450
N/A
Mean Specific Heat @ RT
J/gmK
0.67
0.59
0.67
N/A
Thermal Conductivity @ RT
W/mK
Btu/ft h°F
125.6
72.6
110
64
125.6
72.6
 
N/A
@ 100°C
W/mK
Btu/ft h°F
N/A
N/A
N/A
N/A
29
@ 200°C
W/mK
Btu/ft h°F
102.6
59.3
N/A
102.6
59.3
N/A
@ 400°C
W/mK
Btu/ft h°F
77.5
44.8
N/A
77.5
44.8
N/A
Permeability @ RT to 1000°C
Impervious to gases over 31 MPa
Electrical Resistivity @ RT****
@ 1000°C
ohm-cm
ohm-cm
102-108
0.01-0.2
N/A
102-108
0.01-0.2
>1012
Emissivity
 
0.9
0.9
0.9
N/A
Pore Volume Fraction
%
N/A
4.0-6.0
N/A
N/A
Pore Size
�m
N/A
50
N/A
N/A
*Composition code: Si = free silicon metal;
 C = free graphite; SiC = silicon carbide;
 N = nitrogen; Si3N4 = silicon nitride
       
***RT to 1000°C
****Dependent upon dopants in Hexoloy®SA
      SiC which will decrease electrical resistivity
**Test Bar Size: 3 x 4 x 45 mm
   (0.118" x 0.157" x 1.772")
 

 

 

We supply Hexoloy SiC:

  • Finished components
  • Unfinished tubes and machined blanks - See PDF
  • Pressed near net shape blanks
  • High volume pressed net shape components
  • Complex, highly machined parts

 

Your Source for Hexoloy® SiC Seal Faces...Worldwide

Saint-Gobain Ceramics offers vast resources to meet your needs for silicon carbide products. With representation in Asia by Norton KK (a Saint-Gobain company) and locations in Europe, Australia and South America, we can deliver your solution when you need it, where need you need it, in virtually every corner of the world.

Contact Saint-Gobain Ceramics for more information.