THE
TIODIZE PROCESS:
TITANIUM ANODIZE
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The TIODIZE PROCESS is an electrolytic process
using an alkaline bath which is maintained at
room temperature. It produces anti-galling and
wear resistant properties to the surface of titanium
and its alloys, with no dimensional change.
Fractures of both fatigue and tensile specimens
show that there is NO HYDROGEN PICK-UP
or hydrogen embrittlement; rather, there is an
increase in fatigue strength due to the inherent
complexity of the surface treatment by TIODIZE,
which produces a finish that is an interstitial
part of the metal itself.
- TIODIZE Type I is an electrically semi-conductinve
finish that is used as a pre-treatment for cold
extrusion, hot forging and drawing operations,
as well as a coating for absorptance and emittance.
- TIODIZE Type II provides an anti-galling surface
and is an excellent surface preperation for
dry film lubricants, paints and emissivity coatings.
- TIODIZE Type III is an entirely different
process that produces a spectrum of surface
colors on titanium, but does not offer anti-galling
or wear resistance.
- TIODIZE Type IV is Type II with TIOLON X40
PTFE impregnated into the surface to provide
low friction and anti-galling for longer life
at higher loads.
The most complicated part configurations can
be TIODIZED, including such difficult areas as
blind holes and tubing walls. The throwing power
of the solution gives continuous surface treatment,
even in areas remote from the cathode. Contrasted
with conventional plating, the process causes
a “growth-inward” by the action of both
solution and current. As a result, one of the
most important advantages of the process is in
the area of NO DIMENSIONAL CHANGE.
The TIODIZE PROCESS can be applied on all titanium
surfaces.
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TABLE OF
CONTENTS
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This links in this section require Acrobat
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I. TIODIZE
PROCESSES
AND THEIR USES
TIODIZE
Types
Use
of the TIODIZE PROCESS
Interference
Fit Fasteners
Improved
Surface Finish -Titanium Turbine and Engine Blades
II. TEST RESULTS ON THE
TIODIZE PROCESS
Usage
for Thermal Control: Insat-1 Domestic Satellite
System for India
Absorptance
and Emittance Tests
Vacuum
Outgassing Test
Comparative
Fatigue Test
Fatigue
Tests
LFW
1 Fretting Wear Tests
LFW
1 Unidirectional Wear Test
All
Titanium Sliding Bearing Test
Hypergolic
Fluids Test
Rocket
Propellant Seal Test
Titanium
Actuator Test
III. SUPPLEMENT–TITANIUM
DESIGN CONSIDERATIONS
Basic
Design Facts About Titanium and its Alloys
Fabricating
Properties of Titanium Alloys
Other
Products by TIODIZE
TIODIZE, TIOLON, TIOLUBE, TICOMP, TRIBO/COMP,
FIBER/LITE, RIV/LITE, CHANNEL/LITE, and ALUMAZITE
are registered trademarks of TIODIZE CO., INC.,
Huntington Beach, CA 92649
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ALUMINUM
ANODIZING
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Type II - Clear and all colors
Type III - Hard Anodize
AMS 2468, AMS 2471, MIL-A-8625
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An aluminum oxide coating for improving
the hardness, lubricity and corrosion resistance
of aluminum and aluminum alloys.
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The HARDTUF Process
HARDTUF is a proprietary anodizing process
developed by Tiodize Co. Inc. It is an electrochemical
process for building a lubricative aluminum
oxide coating on aluminum and it provides
an extremely hard, corrosion resistant surface
with high dielectric strength. The process
converts the aluminum surface to aluminum
oxide (Al203H20) and replaces
the H20 with
Tiolon® (PTFE). The HARDTUF MIL Spec
number is MIL-A-63576.
HARDTUF Advantages
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Lubricity |
•
Wear and |
• Mold
Release Properties |
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Corrosion Resistance |
Abrasion Resistance |
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High Dielectric Strength |
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| HARDTUF Processes |
| HARDTUF X20 |
| This process is an impregnation of PTFE
into the unsealed surface asperities of the
oxide coating for better lubricity and mold
release qualities. |
| HARDTUF A20 |
| This process uses a PTFE coating suspended
in a thermoplastic resin and applied by dipping
spraying or brushing the unsealed oxide surfaces.
This air-dry coating allows for better corrosion
resistance and lubricity. |
| HARDTUF E20 |
| In this process, PTFE is suspended in a
thermosetting resin, applied by spraying dipping
or brushing the unsealed oxide surface and
cured at 375°F for one hour. E20 is used
for longer wear life and solvent resistance. |
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Wear and Abrasion
Resistance
HARDTUF resists wear and abrasion better
than other mil spec type hard anodizing
processes.
Lubricity
HARDTUF provides a dry lubricating surface
composed of a PTFE polymer called Tiolon®.
Tiolon® is impregnated into the surface
asperities, thus reducing
surface tension and greatly increasing lubricity.
Corrosion Resistance
HARDTUF is more resistant to corrosion
and most common chemicals due to the interlocking
structure of PTFE and aluminum oxide. Its
sealing effect is responsible for excellent
salt spray resistance and other corrosion
environment tests.
High Dielectric
Strength
HARDTUF is a non-conductor and acts
as an insulator. It will withstand a range
of 1,000 to 2,000 volts, depending upon
its thickness. Standard anodizing films
break down at about 600 volts. HARDTUF becomes
an integral part of the parent metal. It
is the surface of the metal converted to
an oxide and then interlocked with PTFE.
It will not peel or strip; and because of
its hardness, it resists nicks, scratches
and will not flake by ordinary means.
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Numerous applications on a variety of aluminum alloys
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Applications:
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- Molds/die products-used as a mold/die
release to reduce sticking and wear
- Machinery-rotors, gears, bushings, bearings,
etc.
- Electronics-heat sinks, control panels,
capstans, data processing equipment
- Aerospace components-actuators, valves,
impellers, etc.
- Automotive-mechanical parts, racing
pistons
- Marine parts-boat spars, fittings, etc.
- Ordnance-all U.S. service branches require
hard-coating
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Characteristics
as applied to:
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Wrought Alloys
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1100 Series
Most common: 1100 only Bronze-grey in color
at .002 inch,
alloy is soft and not particularly good for
machining. Maximum practical coating thickness
.0025 inch.
2000 Series
Most common: 2014, 2017, 2024, 2618 (forgings).
Avoid sharp corners on 2011 and 2017; grey-black
at .002 inch to blue-grey at .002 inch. Excellent
machining characteristics, Maximum practical
coating .002 inch; .0025 inch possible for
salvage though not as hard as less heavy coats.
3000 Series
Most common: 3003. Good for die work and machining.
Grey-black in color at maximum coating of
.002 inch.
5000 Series
Most common: 5005, 5052. 5005 best for die
work; 5052 not
good for die work, except black. Both have
good machining
characteristics, Maximum practical coating
.002 inch. 5052 has excellent dielectric properties
when coated to .002 inch.
6000 & 7000 Series
Most common: 6061 6063 and 7075. 6061 forms
excellent
hardcoat for grinding, lapping or honing.
Excellent dimensional stability. 6063 used
for extrusions. Maximum practical coating
.0025 inch. 7075 for high strength applications.
Tool Plate
Reynolds and Alcoa make high stability tool
plate (wrought and cast, respectively). Both
can be HARDTUF coated. Maximum practical coating
is .0025 inch.
Ingot
Sandcast Alloys
Most common: 319, 355, 356, also 40E, Ternalloy,
Tenzalloy and a variety of proprietary alloys.
356-T6 is used most often. Grinds and polishes
very well. Porosity can cause apparent pits
in coating. Anodize will not fill in pores.
Maximum practical coating .004 inch.
Die Cast Alloys
Most common: 218, 360, 380. Only 218 produces
hardcoat comparable to that on wrought or
sandcast, 218 is difficult to die cast.
Maximum .0015 inch. 360, 380 maximum about
001 inch. Color is black. Not as wear resistant
as 218.
NOTE: Reason for difference in coating
quality on die casting is that 218 is 9.4%
alloying elements of which the principal is
magnesium. Magnesium is not detrimental to
HARDTUF and, in fact, there are some high
magnesium proprietary sandcasting alloys (such
as Almag 35) which anodize very rapidly and
well, 360 and 380, however, are 11.60% and
13.80% alloying elements respectively, and
the principal elements are silicon and copper.
Both, but specifically silicon, are detrimental
to a good anodic coating. |
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