Toshiba America Electronic Components, (TAEC) Inc., Advanced
Materials Division (AMD) is the largest supplier of silicon nitride ball
blanks to the North American and European precision ball finishing industry.
The Toshiba
TSN-03NH grade silicon nitride is considered by the bearing industry
to be an industry standard due to its high level of performance and quality.
Toshiba silicon nitride combines strength, hardness, toughness,
corrosion resistance, high-temperature capability, and reduced weight.
These attributes make it useful for many applications involving high contact
stress sliding or rolling contact, corrosive chemicals, or high temperatures.
Several successful high-production-volume applications utilizing these
unique characteristics have been developed.
Examples
of improved wear performance
Key Benefits
- No adhesive wear against steel
- Twice as hard as tool steel
- 60% less weight than steel
Proven in Demanding Applications
Silicon nitride is used by the largest bearing companies
in the world, including FAG, Barden, SKF and JTKEKT. It was the only material
to be approved for use in ball and roller bearings in the NASA space shuttle's
main engine high pressure liquid oxygen and liquid hydrogen turbopumps
- one of the most severe applications ever developed for rolling element
bearings. It also helped the Thrust SSC car achieve its record-breaking
Mach 1+ land speed run by allowing the wheel bearings to operate reliably
at over 480,000 dN. Silicon nitride balls have also been used extensively
as check balls in high pressure or corrosive fluid systems. Most major
diesel fuel systems manufacturers are using silicon nitride check balls
today.
The material is lightweight, reduces adhesive wear, and is corrosion
resistant resulting in less wear of both the ball and the check-valve
seat, thereby reducing leakage. Other applications include machine tool
spindles, wind turbines, turbomolecular vacuum pumps, high-performance
bicycles and in-line skates, as well as aircraft APUs
and starter motor/generators and food processing equipment. TAEC-AMD can
supply ball blanks from 1 mm to 2-1/4 inches in diameter, roller blanks
and bearing race blanks, as well as custom manufactured components.
If your application involves high rolling or sliding contact stresses,
this material can handle the load.
More Applications
ASTM Certified
Toshiba TSN-03NH is certified to meet ASTM F2094 Class I
requirements, the highest industry classification for silicon nitride
bearing materials.
Contacts
Toshiba America Electronic Components,
Inc.
Advanced Materials Division
290 Donald Lynch Blvd.
Marlborough, MA 01752
joe.brouillet@taec.toshiba.com
Tel: 508-303-5041
Fax: 508-481-8890
Silicon Nitride for Wear Resistant
Diesel Engine Components
The
amount of wear reduction that silicon nitride can provide is clearly demonstrated
in the Cummins C-Brake™ engine compression brake used on the N14
model heavy-duty diesel engine. Silicon nitride was incorporated into
the master piston in the form of a wear pad. The master piston contacts
a bearing steel adjusting screw head with a force of 2200 lbs while relying
on splash lubrication to prevent wear. The previous master piston material,
D4 tool steel, could not provide the required wear performance under the
higher loads and increased durability requirements of newer engines.
The
novel design was critical to meeting the tight cost target. The design
comprises a lower cost steel body, a simple retaining ring attachment,
and a relaxed tolerance ceramic pad which requires no post-sinter machining.
Toshiba's experience in designing cost effectively with
ceramic resulted in a component with dramatically improved wear characteristics
with a cost that was comparable to the tool steel master piston.
Summary: Silicon nitride in
lubricated sliding contact with steel can significantly reduce total wear,
especially under degraded lubrication conditions. Toshiba has the proven
capability to develop cost effective design solutions incorporating ceramic
elements. More information regarding this application can be found in
SAE paper 930159.
Silicon Nitride Ceramic for
Wear Resistant Machine Elements
Ceramic Advantage: Reduced
Wear and Friction
In
FALEX 1 Block-on-Ring rig testing, silicon nitride-on-steel material combinations
exhibit reduced sliding wear and friction compared to steel-on-steel,
especially in degraded lubrication conditions.
Test Conditions: 120°C
Oil Temperature, 700 MPa Contact Stress, 0 . 55 m/s Sliding Speed, Fresh
and Engine-Tested CD/SF 15W40 Oil.
Results: Silicon nitride-on-steel
exhibited dramatically less total wear and reduced friction compared with
steel-on-steel, even in used diesel engine oil containing abrasive soot
particles. Similar results have been documented with steels other than
52100 and confirmed in actual engine tests.
Benefit Summary: Silicon nitride
can significantly reduce total wear when in lubricated-sample sliding
contact with steel, especially in degraded lubrication conditions. Reduced
friction can reduce parasitic power and energy losses in engines and other
industrial machinery applications.
In
1986, Cummins Inc. introduced the Step Timing Control (STC™) fuel
system to provide improved exhaust emissions to meet tightened emissions
regulations. A by-product of these changes was an increased level of
abrasive soot particles generated during the combustion process and
collecting in the lubricating oil.
The
incorporation of the silicon nitride link dramatically reduced wear
to an acceptable level without requiring additional design changes to
the injector. The increased hardness of the link and the lack of asperity
welding with the steel socket resulted in a reduction in abrasive and
adhesive wear mechanisms. The silicon nitride link has the same geometry
as the steel link it replaced. The spherical ends are precision ground
to within 15 micrometers of the nominal profile. 
