METAL FINISHING SERVICES

Anodizing Overview

Anodizing is an electrolytic passivation process used to increase the thickness and density of the natural oxide layer on the surface of metal parts.  The anodization process is named after the part to be treated, which represents the anode or positive portion of an electrical circuit in an electrolytic solution.

Anodizing increases corrosion and wear resistance and can prevent galling of threaded parts.  Anodic films can also be used for cosmetic purposes; a thick porous coating can absorb dyes (ie. aluminum anodization) or a thin transparent coating can add interference effects to reflected light (ie. titanium anodization). Anodization changes the microscopic texture of the surface and can change the crystal structure of the base metal near the surface.  Anodic films are generally much stronger and more adherent than most paints,  platings, and other coating technologies which makes them less likely to crack and delaminate.  Anodic films are most commonly applied to protect aluminum alloys, although APT has also developed a proprietary, breakthrough process for anodizing  titanium.     

Titanium Anodizing 

Industry Focus: Medical, Aerospace

Medical Devices Anodized with APT’s Brilliant Titanium Anodizing Process

Recent proprietary anodic film process innovations have thrust APT to the forefront of commercial titanium anodizing.  APT achieves high throughput and consistent, brilliant-color quality titanium anodizing.  The most common use of this technology is in medical devices.  See news release on home page.   

Anodized titanium has been used in a recent generation of dental and spinal implants.  The anodic film is composed of a titanium dioxide layer >1 µm in thickness and up to >2.5 µm compared with much less than 1 µm for un-anodized specimens.  Titanium anodic films cannot be made thicker than about 300nm.  Standards for titanium anodizing are given by AMS 2487 and AMS 2488.

Anodizing titanium generates a wide array of colors without using dyes.  This process has been widely accepted to differentiate medical components such as bone screws.  See images below.

High Performance Titanium Anodizing for the Medical Industry:

Devices, Spinal & Implant Components, Bone Screws

Different size components are coded by color to assist the surgeon during surgery.  Color is dependent on the thickness of the oxide layer which is determined through precise process control; it is caused by the interference of light reflecting off the oxide surface with light traveling through it and reflecting off the underlying metal surface.  When the wavelengths of the reflected light are out-of-synch with each other, they will cancel each other and the color that is visible will be dark or not visible at all.  This is called destructive interference.  Depending on the thickness of the anodized oxide layer, the wavelengths of the reflected light may follow each other closely and be in-sync.  The wave strength (amplitude) will be increased, and that particular color would appear brighter.  This is called constructive interference.  See diagrams below.

A  color strip is displayed below to demonstrate the spectrum of colors available with APT’s breakthrough titanium anodization process.

Contact Anodic Process Technology TODAY to learn how we can provide high-quality, fast delivery, and cost-effective titanium anodizing services for your products. Contact Us

Aluminum Anodizing

Industry Focus: All Industries Utilizing Aluminum Components that Require Corrosion Resistance and/or Cosmetic Appeal—Medical, Aerospace, Oil & Gas, Semiconductor, and Automotive for Exampl

 

 

 

 

Aluminum is anodized primarily for two reasons: to increase corrosion resistance and to allow dyeing.  When exposed to the atmosphere, aluminum forms a passive oxide layer which provides moderate protection against corrosion.  In its pure form, aluminum self-passivates very effectively.  However, aluminum alloys--especially 6000 series due to the magnesium content--are much more prone to atmospheric corrosion and benefit significantly from the protective oxide layer.

During aluminum anodization, the aluminum oxide layer is made thicker by passing a direct current through an acid solution, with the aluminum object serving as the anode, which is the positive electrode.  The electrical current releases hydrogen at the cathode (the negative electrode) and oxygen at the surface of the aluminum anode.  Therefore, a build-up of aluminum oxide is created, which is essentially a ceramic coating having characteristics of high hardness and high corrosion resistance.   

APT offers Type II and Type III aluminum anodizing processes, which have been perfected over the past 15 years.  The most common anodizing specification is MIL-A-8625, which defines three types of aluminum anodization. Type I is Chromic Acid Anodization, Type II is Sulphuric Acid Anodization and Type III is sulphuric acid hardcoat anodization.  Type II anodizing (room temperature) creates an anodic layer of aluminum oxide that is 0.0002" to 0.001" thick (approximately half which is grown into the surface and the other half above the surface).  By introducing dye into the anodization process, various colors can be obtained.  APT’s stringent process controls yield consistent, brilliant colors from lot-to-lot.  See images below.

Various Industrial Aluminum Products Anodized with APT’s Unique Process Technology

Type III (hard coat) anodizing is performed at much colder temperatures and at higher current densities and can reach thicknesses of 0.002" – 0.004”.  Type III anodized surfaces are commonly dyed black or dark green due to the denser pore size.

Contact Anodic Process Technology TODAY to learn how we can provide high-quality, fast delivery, and cost-effective aluminum annodizing services for your products.  Contact Us

COSMETIC APPEAL/DECORATIVE

Industry Focus:  Sport Enthusiasts, Custom Automotive Accessories, Hobbyists: Small Runs or Production Volumes.

APT has developed process technology to turn an ordinary or utilitarian metal product, toy, or hobby into a beautiful sight to behold.  From CO₂, paint ball, and air gun tanks to automotive accessories, contact APT today with your requirement for small custom runs to large production volume processing.  Decorate and personalize your life with style.

Aluminum Tools Creatively Stylized with APT’s Unique Anodization Process Technology   

Electropolishing

Industry Focus: Medical, Oil & Gas, Various Industrial 

Corrosion Resistant Metal Finishing for the Oil & Gas Industry

APT offers electropolishing of stainless steel and titanium.  We specialize in electropolishing industrial metal components for the Oil & Gas and Medical Industries.  Electropolishing is an electrochemical process which polishes the surface of a metal by removing a microscopic amount of material from the part.  The electrochemical process employs an acidic viscous medium for the transportation of ions allowing surface undulations to form a more planar surface finish.  APT’s electropolishing process results in parts that are bright, smooth, and possess a more corrosion resistant finish.

Our ability to electropolish odd-shapped metal parts of virtually any size within one-two days with the same outstanding surface finish from lot-to-lot is unmatched in the industry.  In order to achieve the desired level of polish and localized areas of polish, the size, position, and distance of the cathode to the part must be precisely controlled.  In electropolishing, the metal part is immersed in a temperature controlled electrolyte bath and connected to the positive terminal or anode of a DC power supply.  The negative terminal is attached to a cathode to which the particles removed from the metal part are attracted when electric current is applied.  Anodic Process Technology’s experience and process control result in outstanding electropolishing results.   See image below:

 

High Performance Electropolishing for the Medical Industry 

Contact us TODAY to learn how we can provide high-quality, fast delivery, and cost-effective electropolishing services for your products.  Contact Us

Electroless Nickel Plating

Industry Focus: All Industries Utilizing Metal Components that Require Corrosion or wear Resistance, and/or Cosmetic Appeal —Medical, Aerospace, Oil & Gas, Semiconductor, and Automotive for Example.

APT offers electroless nickel plating, which is a processing method used to deposit a layer of nickel-phosporous alloy on a metal or plastic part.  Alloys with different percentage of phosphorus, ranging form 2-5 (low phosphorus) to up to 11-14 (high phosphorus) are possible. The metallurgical properties of alloys depend on the percentage of phosphorus.

Electroless nickel plating is an auto-catalytic reaction used to deposit a coating of nickel on a substrate. Unlike electroplating, it is not necessary to pass an electric current through the solution to form a deposit. This plating technique is employed to prevent corrosion and wear.

Electroless nickel plating has several advantages versus electroplating. Free from flux-density and power supply issues, it provides an even deposit regardless of component geometry, and with the proper pre-plate catalyst, can deposit on non-conductive surfaces.

Because electroless nickel plating produces a non-toxic coating, it is commonly used in medical devices.  Other applications include optical surfaces for diamond turning,  electrical/mechanical tools, and various industrial equipment.   

Contact us TODAY to learn how we can provide high-quality, fast delivery, and cost-effective electroless plating services for your products.  Contact Us

Passivation

APT offers passivation services, which is the treatment of stainless steel or titanium surfaces with our proprietary processes and solutions.  Passivation removes contaminants and promotes the formation of the passive film on a freshly created surface.

APT’s passivation treatments penetrates and cleans the steel surface and removes free iron contaminants.  We use care in developing and using passivation treatments to ensure the selected treatment will target the contaminant.  Passivation will also aid in the rapid development of the passive oxide film on the metal's surface.  Passivation does not usually result in a change in appearance of the metal’s surface.

The corrosion resistance of stainless steel is affected by the roughness of the surface after machining or polishing.  As the surface roughness increases above an R_a value of approximately 0.5 microns, a significant decrease is corrosion resistance is obtained.  0.5 microns R_a roughly corresponds to the surface produced by grinding with a 320 grit wheel.  Either passivation or electropolishing can be used to improve the corrosion resistance of mechanically machined and polished surfaces.

Contact us TODAY to learn how we can provide high-quality, fast delivery, and cost-effective passivation services for your products.  Contact Us