Tufram

Surface Enhancement Coatings Protect Aluminum and Aluminum Alloys

Against Wear, Corrosion, Sticking and Galling

 

Dramatically increase surface hardness

Resist corrosion, chemicals, and acids

Prevent abrasive wear and galling

Provide superior mold release

Meet AMS 2469 and AMS 2482

Offer high dielectric strength

Permanently self-lubricating for extended wear

Many meet FDA, USDA, NSF, and AgriCanada codes

Speed cleanup and sanitation maintenance

No outgassing in the vacuum of space

Low COF eliminates sticking and product “hang up”

Won’t chip, peel, or flake off like “paint-ons”

Meets the End of Life Vehicle (ELV) initiative for the automotive industry

 

Although TUFRAM coatings were first developed to solve critical wear and performance problems plagu- ing aluminum parts on NASA’s space vehicles, engi- neers worldwide soon recognized them as the solu- tion to a host of problems faced by aluminum com- ponents on all types of manufacturing, processing and packaging equipment.

Created in a proprietary, multi-step process that makes aluminum surfaces harder than steel, TUFRAM coatings combine the hardness of aluminum oxide ceramic with the desirable properties of selected Magnaplate proprietary polymers to give aluminum parts previously unattainable levels of hardness, wear and corrosion resistance, as well as permanent lubricity.

Since the surface is superior in performance to both the aluminum or any of the individual components used in the process, Magnaplate-applied TUFRAM coatings are identified as “synergistic.”

Engineering Data and Performance Characteristics

Corrosion resistance

TUFRAM coatings exhibit much greater corrosion resistance than conventional hard anodizing. Some types show extremely high resistance to most common chemicals and salt spray. Tests show no effect after 168 hours immersion in Aqua Regia at 248°F (120°C). A TUFRAM-coated surface showed almost no corrosive activity after prolonged, continu- ous exposure to the atmosphere and salt water. In addition, TUFRAM enhancements on high strength aluminum exceed the AMS 2482 requirement of a minimum of 336 hours in salt spray.

When maximum corrosion resistance on aluminum is required, MAGNAPLATE HCR®, which provides 40 times the required protection, is recommended.

Abrasion resistance

A smooth surface substrate produces the most abra- sion-resistant TUFRAM finish. Taber abrasion measure- ments show that its wear resistance is far better than either case-hardened steel or hard chrome plate. No matter what other metal rubs against the TUFRAM coating, it too will show only slight wear.

Friction

In some cases, the static friction decreases with an increase in load. TUFRAM eliminates “stick-slip” and undesirable vibration of higher break-away friction. For more information, see General Magnaplate’s Friction Data Guide.

Hardness

Varies from equivalent hardness of Rc 40 to Rc 65, depending on the TUFRAM chosen and alloy used.

Adherence and impact resistance

TUFRAM coatings adhere firmly to most alloys, espe- cially those containing magnesium. Impact resistance is limited only by the structural strength of the base metal to which they are applied.

FDA/USDA/NSF/AgriCanada compliance

Compliance with FDA, USDA, NSF, and AgriCanada codes makes most TUFRAM coatings advantageous for food and pharmaceutical processing and packaging, and some medical industry applications.

Temperature

Exhibits high strength, toughness, and self-lubricity down to –360°F (–218°C), and intermittent operating capability at temperatures as high as +800°F (+427°C), depending upon the process specified and the alloy used.

Non-stick release properties

Very few solid substances, even adhesives, adhesive- backed products or glues, will permanently adhere to the proprietary-polymer-impregnated surface of a TUFRAM-coated part. Most substances, such as plastics, rubber or slurries, release easily. Some extremely tacky materials may exhibit mild temporary adhesion.

Self-lubricating surface

Proprietary polymers impregnated into the aluminum during the TUFRAM process level off surface asperities to provide a permanent self-lubricating surface, and result in greatly reduced surface tension. TUFRAM- coated parts exhibit a longer wear-life, require less maintenance, and provide greater operating efficiencies with less downtime. Mating parts that operate with a sliding or rotating motion experience a dramatic reduction in friction.

Resistance to acid and alkaline solutions

TUFRAM 600 Series coatings provide superior resis- tance to attack from acid or alkaline solutions and atmosphere. In humidification tests, panels with one edge exposed by a saw cut were immersed in acid with a pH range of 3.5 – 4.0 and in an alkaline solution with a pH range of 8.5 – 9.0. Both panels protruded for half their lengths to provide immersion and vapor tests simultaneously. After 90 days, saw cut edges on both panels were badly corroded. Heaviest damage occurred at interfaces of the liquid and vapor states. However, TUFRAM-treated surface areas showed no effect.

Non-wetting

The new, integral surfaces are oleophobic and hydro- phobic, and resist wetting by most liquids. Cleanup is faster, easier, and more thorough. Parts become self- cleaning. Maintenance time and labor are greatly reduced.

Weather resistance

Tests of TUFRAM-coated samples, exposed for years to severe climatic conditions, confirm its resistance to all types of weather. TUFRAM coatings also exhibit excel- lent resistance to ultraviolet light and extreme heat.

Performance in vacuums

Initially developed for use by NASA, TUFRAM coatings have been applied to parts on every space vehicle since the start of the program. They are required to perform in extreme environments, including vacuums to 10–6 torr and temperatures from –100°F (–73°C) to +350°F (+177°C), and under conditions of extreme vibration. Today, they are used in vacuum packaging and on machinery that must operate under vacuum.

Application to aluminum alloys

Aluminum and its alloys that contain less than 5% copper and 7% silicon and that do not contain exces- sive zinc or lead are most suitable for the application of TUFRAM coatings. Most cast, forged, extruded or wrought alloys can be treated. The degree of hard- ness or penetration does vary with some alloys.

Coating tolerances / thickness

With few exceptions, a consistently uniform coating can be applied to parts of any configuration or weight, and virtually any size or thickness. Precise control of thickness permits use on threaded mem- bers and similar close-tolerance applications. By undersizing outside pitch diameter by roughly twice the coating thickness prior to coating, original thread sizes are maintained.

Dielectric properties

The TUFRAM process converts the aluminum surface to one with excellent dielectric characteristics, without affecting the high conductivity of the parent metal. The proprietary-polymer impregnation imparts out- standing properties as an insulator. The polymers do not absorb water. Volume resistivity values remain unchanged, even after prolonged soaking in water. Surface resistivity values were taken at 100% relative humidity. Dielectric constant for the polymer remains constant at 2.1 for a temperature range of –250°F (–157°C) to +550°F (+288°C) and a frequency range of 5 Hz – 10,000 MHz. Dissipation factor is also constant at 0.0003 for the same ranges of temperature and fre- quency. Non-conductive TUFRAM acts as an insulator that withstands a range of 500 – 2,000 volts, depend- ing upon thickness.