Protech is a woman-owned full-service metal finishing company that has served customers since 1980.  Protech is housed in a 32,000 square foot facility on 10 acres in Vonore, Tennessee. Specializing in anodizing and rack plating. Protech services a large customer base in the Aerospace, Defense, Industrial, Medical and Automotive fields. We lead the industry in recruiting and retaining the most experienced plating and support personnel in the region.

Quality System – Protech maintains NADCAP quality system.

Meeting Rapid Turnaround Time – Our customers have found us to be a reliable supplier offering unsurpassed service, rapid turnaround, top-notch quality at the most competitive prices.

Environmental Health and Safety – Protech Metal Finishing has made a commitment to environmental health and safety. We are working on developing innovative methods to protect our environment. We utilize our Research and Development laboratory to successfully reduce waste and promote shop floor operator education.

Engineering and Testing – Our in-house laboratory and testing capabilities provide us with unique advantages in the metal plating industry. It enhances our production methods to improve the performance of our customer’s products as well as our service offerings.

We meet all testing requirements for the specs we process.

Customer Support Service – Our experienced staff is available to advise customers on technical questions. In addition, our production control and management personnel are available to answer customer questions on scheduling and delivery.

TYPE I – CHROMIC ACID ANODIZE
Chromic acid coatings are frequently preferred if there is a possibility of solution entrapment in joints, recesses, and weldments because the chromic acid leaves no corrosive residue. The chromic acid is inhibitive to aluminum and, thus, is especially good for coating aluminum castings.
Chromic acid-produced films are dense, very thin (0.00002″ to 0.0007″ thickness range), and darker in color. Chromic acid films are typically harder than sulfuric acid films of the same thickness.
Type IB is low voltage chromic acid anodizing.  Best for 7000 series alloys.

PROPERTIES OF TYPE I ANODIZING:

• Corrosion Resistance: The aluminum oxide film is resistant to atmospheric and saltwater environments.
• Electrical Insulation: Aluminum oxide film is dielectric.
• Paint Adhesion: Aluminum oxide film is a chemically active surface for painting.
• Adhesive Bonding: Aluminum oxide film improves adhesion and bond strength.
• Salt Spray Corrosion Test (minimum 336 hours of salt spray resistance)

TYPE II – SULFURIC ACID ANODIZE

The sulfuric acid process is the most common method for anodization. The sulfuric acid process produces films of greater thickness (0.00007″ to .001″ thickness range) and is particularly suited for applications where hardness and resistance to abrasion is required. However, where parts are subjected to considerable stress, such as aircraft parts, the possible presence of the corrosive acid residue is undesirable. The overall thickness of the coating formed is 67 percent penetration in the substrate and 33 percent growth over the original dimension of the part.

Class I is clear anodize.

Class II is colored anodize.  The porous nature of sulfuric acid films prior to sealing is used to particular advantage in the production of colored surface finishes on aluminum and its alloys. The porous aluminum oxide absorbs dyes well, and subsequent sealing helps to prevent color loss in service. Some of the colors produced at Protech are:

• Black
• Red
• Blue
• Purple
• Pink
• Gold
• Custom colors are available upon request and may require a special setup.

Type IIB is thin film sulfuric acid anodize.

Protech offers three types of chemical finishing prior to anodizing:

1. Nonetched cleaning – Soap cleaning and degreasing.
2. Etched – Caustic soda etch for medium matte.
3. Brightened – Chemical dip solution of acid type.

PROPERTIES OF TYPE II ANODIZING: 

• Corrosion Resistance: The aluminum oxide film is resistant to atmospheric and saltwater environments.
• Electrical Insulation: Aluminum oxide film is dielectric.
• Paint Adhesion: Aluminum oxide film provides an excellent surface for painting.
• Adhesive Bonding: Aluminum oxide film improves adhesion and bond strength.
• Cleanability: Anodized coatings withstand the hydrogen peroxide commonly used in medical sterilization.
• Salt Spray Corrosion Test (minimum 336 hours of salt spray resistance)

TYPE III – HARD ANODIZE

The hard anodizing process also uses a sulfuric acid electrolyte, but the bath is maintained at a lower temperature and higher current density, which increases film crystallinity.

Nominal thickness of 1 to 2 mils is common for most applications. The overall thickness of the coating formed is 50 percent penetration in the substrate and 50 percent growth over the original dimension of the part.  Parts processed by this method have a hardness of 65 Rockwell “C”. Hard anodic coatings generally have increased surface roughness as well as having the property of being softer on the top surface than down in the core of the coating. Such coatings may be processed oversized and then lapped down to final dimensions. Lapping of a hard anodized surface results in an exceedingly smooth, hard finish resembling polished stone. Hard anodizing is an excellent electrical insulator, and base for paint, dry film lubricants and other coatings.

The color will vary from light tan to black depending on alloy and thickness. The term THICKNESS includes both the buildup and penetration.

Sealing of hard coating is not recommended unless corrosion resistance is a factor. Wear resistance is sometimes reduced by sealing. Hard coatings may also reduce fatigue strength. These factors should be considered in proposed use of parts subjected to cyclic loads. Generally, hard coatings should not be used on parts, which during rework would normally require restoring of dimensional tolerances because of wear of hard coated surfaces.

When the hard anodize is impregnated with PTFE, the coating not only has great wear and abrasion resistance, but also now has improved lubricating properties. Some applications for the impregnated coating are; valves, sliding parts, hinges, cams, pistons, and gears.

PROPERTIES OF TYPE III HARD ANODIZING:

• Compatible with adhesives
• Excellent lubricity (enhanced by PTFE impregnation)
• Resistant to marine and atmospheric corrosion
• High operating temperatures
• Electrically resistant
• Galvanic neutrality (prevents galvanic corrosion from interaction between dissimilar metals)

ANODIZING BASICS – Before we anodize your parts, there are several important things we need to know:

• What process do you need? Type I, Type II or Type III (soft or hard anodize)?  Is there a specification to meet?  Will the job require a certificate of compliance to the spec?
• What color do you want?  Class 1 (clear) or Class 2 (color)?  If a color is required, do you have a color sample?  If not we default to our standard color shades.
• What material alloy are you using?  This affects how long we etch (material removed) and how long we anodize (material added back).
• Are there any critical dimensions we need to inspect/watch closely?
• Do you have any holes or surfaces that need to be plugged or masked? (e.g. left un-anodized for grounding purposes)?
• Are there any areas we need to avoid when racking the parts or specific areas where you would prefer us to rack?  (If not specified we will rack in the most effective manner).

NOTE: It is important that there be no steel or stainless steel pins, screws or hardware in the parts.  These will be dissolved during anodizing process.

CHROMATE CONVERSION

Chromate Conversion, also known as Chem-Film, is a coating that chemically reacts with the surface of the material to form a soft gelatinous film when first applied. After time the film hardens and becomes hydrophobic. It’s purpose is to provide maximum corrosion protection to aluminum and act as a base for paint primers. Conversion coatings are typically very thin, around 0.00001″.

ZINC ELECTROPLATING

Zinc electroplating is one of the more versatile finishes and can be chromated different colors after plating to achieve different results for a product.  Zinc is an excellent, inexpensive, decorative, and sacrificial protective coating against corrosion of steel and iron parts.  Zinc is further protected by an application of chromates and sealers, which help prevent corrosion of both the zinc and the base metal.

Clear is hexavalent free.

Yellow can be used as is, or as a paint base.

Olive Drab is usually used for military applications.

ELECTROLESS NICKEL

Electroless Nickel is an autocatalytic process that does not use electric current to produce the coating. The process deposits a uniform nickel phosphorous alloy to the metal, regardless of the shape of the part or its surface irregularities. Medium phosphorous electroless nickel is the most common because it’s bright, hard, and corrosion resistant. We offer medium phosphorus and Electroless Nickel with Teflon.

PASSIVATION

Passivation is the chemical treatment of a stainless steel with a mild oxidant, such as a nitric acid solution for the purpose of enhancing the spontaneous formation of the protective passive film.

PROCESS LISTING BY SPECIFICATION

Specification:                            Process:

MIL-A-8625F                 Anodize Type I, II, & IIB, III

AMS-A-8625                 Anodize

AMS-A-2468                 Hard Anodize

MIL-DTL-5541F             Conversion Coating Type 1 or 2

AMS-C-5541                 Conversion Coating

MIL-DTL-16232G           Manganese Phosphate Coating

TT-C-490G                    Conversion Coatings & Pretreatments

AMS 2486E                   Titanium Conversion Coating

AMS 2700F                   Passivation-Method 1, Type 1-3 & 6, Nitric

AMS 2700F                   Passivation- Method 2, Citric

ASTM A967M -17          Passivation- Nitric 1, 2 & 4

ASTM A380                   Cleaning & Descaling of Stainless Steel

ASTM B633                   Zinc electroplating

ASTM B733                   Electroless Nickel

MIL-DTL-32119             Electroless Nickel