Chrome Plating Alternative Services – Tin/Cobalt

Chrome Plating Alternative Services (Company) – Tin/Cobalt

Chrome Plating Alternative

Advanced Plating Technologies, a Milwaukee, Wisconsin company, offers innovative tin/cobalt as a chrome plating alternative that provides a similar blue-bright appearance to decorative chrome.  Unlike traditional chrome, tin/cobalt chrome plating alternative is fully RoHS compliant and can be barrel plated.  Your company can realize significant cost savings on smaller products over traditional chrome due to the mass loading and unloading afforded by bulk barrel plating.  Savings as high as an order of magnitude (10x) have been realized.  Tin/cobalt chrome plating alternative is also an excellent choice to provide a brilliant chrome-like appearance on products that must meet RoHS compliance (hexavalent chrome free).

Advanced Plating Technologies’ tin/cobalt chrome plating alternative can be deposited over an underplate of bright nickel for a bright-chrome appearance or can be plated over a grained or electroless nickel underplate to achieve a satin-chrome look.  Our company has worked with numerous manufactures in various industries to employ our tin/cobalt chrome plating alternative where traditional chrome plating had been used, thereby eliminating hexavalent chrome on their product.

Current industry applications of APT’s tin/cobalt chrome plating alternative include the medical, fastener, hardware, hand tool, appliance and electronics markets.  Specific application examples include appliance hinges and hardware, small hand tool components, decorative fasteners and interior trim pieces such as lock bezels.

Chrome Plating AlternativeAdvanced Plating Technologies’ tin/cobalt chrome plating alternative has proven to provide up to double the corrosion protection of a similar deposit of traditional hexavalent chrome over an equal nickel underplate.  However, the corrosion protection offered by APT’s tin/cobalt chrome plating alternative is different than that seen by hexavalent chrome in terms of cosmetic attributes from neutral salt spray testing per ASTM B117.  The primary mechanism that a traditional chrome deposit protects a substrate is by forming a dense oxide film on the surface of the chrome metal.  The chrome oxide acts as a passive barrier and is transparent to the human eyes, lacking a visible “tarnish” as is common with other metallic deposits.

Tin/cobalt chrome plating alternative does not protect in the same manner since it is not a chrome deposit.  While the substrate protection of tin/cobalt is equal or superior to that seen from hexavalent chrome, the surface of the deposit can exhibit a slight tarnishing when subjected to accelerated corrosion testing per ASTM B117.  Service conditions of traditional chrome deposits are well defined in ASTM B456, “Electrodeposited Coatings of Copper Plus Nickel Plus Chromium and Nickel Plus Chromium.”  The five service conditions listed are as follows:

Service Condition 5 – Extended Severe Service
Service Condition 4 – Very Severe Service
Service Condition 3 – Severe Service
Service Condition 2 – Moderate Service
Service Condition 1 – Mild Service

Advanced Plating Technologies generally recommends the use of tin/cobalt chrome plating alternative for most SC 1 and SC 2 applications and in some instances SC 3 environments.

APT’s tin/cobalt chrome plating alternative has been proven to outperform traditional chrome plating over an equal nickel underplate as measured by time to substrate corrosion (e.g. red rust on steel).  If a specific corrosion performance is required, the type, thickness and number of underplates used can be engineered to meet your finishing requirement (reference:  What causes metals to oxidize or “rust” in our Plating Topics section).

Chrome Plating Alternative

Nickel Plated Fitting on Left Compared to Tin Cobalt Plated Fitting

Advanced Plating Technologies’ tin/cobalt chrome plating alternative is a simultaneous codeposit of approximately 78% tin / 22% cobalt commonly applied over an underplate of bright nickel or electroless nickel.  Since the tin/cobalt chrome plating alternative is a combination of both tin and cobalt, the properties of the coating exhibit similarities of both metals.

Tin/cobalt is not as resilient as chromium in highly abrasive applications.  When tested per ASTM D968, the weight loss of tin/cobalt chrome plating alternative is an average of 0.8mg versus 0.9 mg for that of chromium. This testing shows that tin/cobalt chrome alternative is in an acceptable range of wear for most applications with hardness of approximately 70-80% that of chromium.  This hardness is consistent with that of most electrolytic bright nickel deposits.

Tin Cobalt Chrome Plating Alternative

CIE Color Space

The appearance of tin/cobalt chrome plating alternative is a key attribute as it is often used to substitute traditional chrome deposits.  Our company employs stringent color quality control measures to develop customer-specific color standards.  Lots processed are quantitatively measured against these standards to verify the color of tin/cobalt chrome alternative deposits.  Spectrophotometer measurements of the plated deposits to the CIE Lab (1976) color space can be provided with each lot processed.

The CIE Lab (CIE L*a*b) is the most complete color space specified by the International Commission on Illumination.  It describes all colors visible to the human eye and plots them in a three dimensional graph where the L-axis represents light-to-dark, the A-axis represents the green-to-red shades and the B-axis provides the blue-to-yellow colors.  Advanced Plating Technologies pioneered the use of this technology in gold plating and currently utilizes the equipment and methods to maintain tight color control over all alloy deposits including tin/cobalt chrome plating alternative.

 

Chrome Plating AlternativeTin/cobalt chrome plating alternative is a relatively new technology which has recently found growing application with the advent of RoHS compliance and general environmental regulations/concerns about traditional chrome plating.  Due to this fact there are presently no ASTM, MIL or SAE/AMS specifications which address tin/cobalt chrome plating alternative.

A number of major manufacturers in various industries have adopted company specific tin/cobalt specifications.  Our company has been able to meet all of these specifications to date and can provide certifications to such company specifications if required.  If needed, APT’s certified finishing engineers can pair with engineering and design teams to help identify key attributes and develop a specification that meets the desired functionality of a product design.

Tin/Cobalt Chrome Alternative Plating Services – Why APT?


Specifications:
Most Company Specifications


Finish Type:
Bright-Blue, Chrome-Like Appearance (Over Bright Electrolytic Nickel)
Semibright-Blue, Chrome-Like Appearance (Over Electroless Nickel)


Substrates Plated On:

Ferrous: All Ferrous Alloys Including Mild Steel, Stainless Steels, Hardened Steels & Tool Steels
Cuprous: All Cuprous Alloys Including Pure Copper, Copper Alloys Including Tellurium & Beryllium, Brass, Nickel-Silver
Aluminum: All Aluminum Alloys Including Wrought, Cast and Proprietary Alloys (MIC-6)
Exotics: Inconel, Pure Nickel (Nickel 200), Cobalt-Chrome (MP35N), Kovar, Monel, Hastalloy, Monel, Lead


Part Size Limitations: 28 Inches x 28 Inches x 10 Inches


Underplates Provided:
Bright Electrolytic Nickel
Electroless Nickel


Heat Treatments:
Hydrogen Embrittlement Bakes
Stress Relieving Bakes


Methods:
Barrel
Rack
Wire
Vibratory
Selective Loose Piece Plating
Sheet Product (Chemically Milled/Etched Sheets)
Segmented Strips (Frets)