Nickel-Chromium Plating In-House

Article From: Products Finishing, , from Products Finishing

Posted on: 4/1/1998

Progressive Custom Wheel brought nickel-chromium plating in-house to improve quality and lower costs...

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COPPER-PLATED wheels

COPPER-PLATED wheels prior to nickel/chromium plating.

preplate cycle

WHEELS processed through the preplate cycle at Progressive Custom Wheel.

A car is not simply transportation anymore. A car makes a statement about the driver. And drivers want to make a statement with their cars. Witness the increase in demand during the past four years for chromium-plated wheels. Not just any type of chromium-plated wheels, but ones with intricate, bold and elegant designs.

Most often, these "designer" wheels are added after the car is purchased. Progressive Custom Wheels, Riverside, California, is one of the country's leading suppliers of aftermarket wheels. It designs, manufactures and finishes thousands of wheels each week. This thirteen-year-old company was founded by three men who had been in the wheel business since their careers started: Wallace "Mo" Kreag, Sandy Smart and Larry Kingsland.

The company has since grown to include three plants on 25 acres in Riverside. The company has 60 warehouses around the country where it stocks a multitude of wheel types and designs. The company manufactures four basic types of wheels.

The four types include one-piece aluminum, two-piece aluminum, composite wheels (cast aluminum with a steel rim) and a steel wheel with a steel center welded to the rim. Progressive does not cast steel wheels; it only casts aluminum wheels. Also, two-piece wheels are not plated; they are polished and buffed, giving them the look of a plated wheel.

In April of 1997, as part of a cost saving and quality control move, the company brought nickel-chromium plating of aluminum wheels in-house. This was not popular with the neighbors and required much political maneuvering on the part of the company.

To assist with installation and startup, Progressive hired Gary Madrigal to design, engineer and install the four plating lines. Mr. Madrigal designed the layout of the two manual and two automated lines.

The automated lines handle wheels up to 20 inches in diameter by 12 inches wide. Auxiliary anodes are used with about 50 pct of the wheels.

Progressive starts by lowering the aluminum wheels into the Atotech SoakTM 115, a mildly alkaline, low-pH cleaner. Wheels are then etched in Alklean 77, a 100-pct active alkaline etch that contains chelating agents and an inhibitive grain-refining agent. This process produces a uniform stain etch on the aluminum wheels. It can provide a number of decorative finishes simply by controlling the temperature and/or concentration of the bath.

Prior to zincating, wheels are microetched in Alum-Etch-G. The zincate process is Alumseal W-2000. It produces a thin film on the aluminum wheels. It also removes aluminum oxide and applies a zinc film that can be directly plated with copper and/or nickel. Because Progressive double zincates its wheels, the wheels go through Alumseal Activator BD zincate strip.

Once the wheels are zincated a second time, they go into a nickel strike, Permalume G, which produces a semi-bright deposit over a wide current density range. The finish is highly ductile and has low tensile stress. Following the nickel strike, wheels are copper plated with Cupracid 300. This is an acid copper sulfate process that produces bright, ductile deposits with low internal stress and excellent leveling.

After copper plating, parts are submerged in Trimax 349 alkaline, non-silicated heavy-duty soak cleaner. This removes any grease or oil that may have deposited on the wheels and prevents the dirt from redepositing on the wheels. After rinsing, parts are placed in Trimax 279 CA electro-cleaner, which is a high-performance, high-current-density, reverse-current electrocleaner base. The third cleaner is a mildly alkaline, low-temperature liquid spray cleaner that removes a variety of soils by displacement.

The acid prep step follows. Progressive uses Actisal No. 6, a blend of acid and accelerators. It speeds attack on rust and scale and retards attack on the base metal. The process removes silicate films left by silicate-inhibited cleaners in preceding steps. It also removes smut.

The high-leveling, semi-bright nickel plating process, Niflow, is a non-coumarin containing process. The deposit on the wheels is sulfur free, ductile and intended for use as the initial layer in Progressive's decorative duplex-nickel chromium plating process. The solution is continuously filtered through carbon to minimize contamination. The deposit is relatively bright, even though only a thin layer of nickel is put down.

This is followed by Gemini 850 bright nickel plating process that provides high leveling and good ductility. This nickel process provides a whiter and more brilliant finish.

Microporous nickel is also plated onto the wheels. This process, BNX 600, is a bright nickel plating process with excellent leveling and brightness. It provides a brilliant deposit and good chromium receptivity. The BNX bath uses several additives, including the Clepobrite BNX starter/leveler nickel plating additive, which is a blended two-component system plus a wetting agent. This additive allows for bright plating even in low-current-density areas.

TABLE I—Plating Process for Aluminum Wheels (double rinses between each step)
Process Temperature Time Concentration ASF
1. Atotech SoakTM 115 160-175F 3 min 8-10 oz/gal  
2. Alklean 77 alkaline etch 105-115F 1 min 4-6 oz/gal  
3. Alum-Etch-G
microetchant desmut
95-105F 1 min 18 pct by volume  
4. Alumseal W-2000
zincate process
72F 2 min 55 pct by volume  
5. Alumseal Activator BD
zincate strip
75F 1 min 6 oz/gal  
6. Alumseal W-2000 72F 1 min    
7. Permalume G
nickel strike
140-145F 15 min NiSO4 40 oz/gal
NiCl2 9 oz/gal
Boric acid 5.5 oz/gal
Addition GL-1 5 pct by volume
Nickel additive 0.13 pct by volume
20-100 asf
8. Cupracid 300 78F 60-80 min CuSO4 30 oz/gal
H2SO4 7.7 oz/gal
Cl ion 115 ppm
Brightener 0.30 pct by volume
Leveler 0.55 pct by volume
Wetter 0.30 pct by volume
Cathode 10-60 asf
Anode 5-25 asf
9. Trimax 349
soak cleaner
165F 1-5 min 8 oz/gal  
10. Trimax 279
electrocleaner
175F 2 min 10 oz/gal 6-12 volts reverse
11. Spray cleaner 105F 1 min 0.5 to 5 pct by volume  
12. Actisal No. 6 ambient 15-30 sec 10 oz/gal  
13. Niflow semi-bright
nickel
140F 60-120 min NiSO4 40 oz/gal
NiCI2 7 oz/gal
Boric Acid 6 oz/gal
Niflow additive 1 pct by volume
40 asf
14. Gemini 850
bright nickel
143F 20-30 min NiSO4 35-40 oz/gal
NiCl2 10-12 oz/gal
Boric acid 6 oz/gal
Brightener 2 pct by volume
Leveler 0.1 pct by volume
20-80 asf
15. Micro-Porous
Nickel
135F 3 min    
16. Envirochrome 300 115F 3-5 min Chrome A salts 24 oz/gal
SO4 0.12 oz/gal
Chromic acid/sulfate ratio 200:1
150 asf

Another additive is the BNX Super Level, which provides fast leveling and a whiter, more brilliant finish.

The chromium plating process employed is Econochrome 300. This is a dual-catalyst chromium plating solution that operates with relatively low metal concentrations. The bath contains a self-regulating catalyst that enhances the action of the usual sulfate catalyst. The finish has excellent color and yields bright deposits over a broad range. The special catalyst simplifies activation of the base nickel on the wheels.

The manual plating lines are used to plate oversize wheels, such as wheels for semi-trucks. It is also used to plate wheels having intricate designs with deep recesses. Mr. Madrigal believes that by using the hand line, you ensure that all areas of the wheel are plated.

The hand line uses McGean-Rohco chemistries. The liquid soak cleaner, LSC-349, is a concentrated detergent for cleaning sisal-buffed steel. It also removes oil, polish, grease and oxides.

The liquid soak cleaner is LEC-279, which contains detergent, alkalis, wetting agent and complexing agents.

The hand line uses the Besplate RLS semi-bright nickel plating process. It is a three-component system that produces sulfur-free, low-stress, ductile and semi-bright nickel deposits that are suitable for mechanical satin finishing or buffing.

The Reflecta single-additive bright nickel plating process that follows provides good leveling, which is needed with the intricately designed wheels. The process also contains a special additive that makes it suitable for plating die cast wheels.

Econo-Chrome 300 is used for chromium plating on the manual lines. The plating system features a special catalyst that gives the plating bath excellent tolerance to dragin of undesirable catalytic ions, such as sulfate.

TABLE II—Manual Nickel/Chromium Plating Line (double rinse between each step)
Process Temperature Time Concentration ASF
1. Actisalt ambient 3 min 8 oz/gal  
2. Besplate R/L/S
semi-bright nickel
128F 60-120 min   40 asf
3. Reflecta bright
nickel process
140F 20-30 min   Cathode 45 asf
Anode 20 asf
4. Econo-Chrome 300 115F 1-5 min H2CrO4 20-35 oz/gal
Sulfate 0.11-0.20 oz/gal
100-200 asf

You might think that "mixing" these chemistries from different suppliers would be a problem. Not so for Mr. Madrigal. Mr. Madrigal explained, "It keeps the competition tough and the prices competitive." Also, one has to simply look at the finished product to know that Mr. Madrigal knows how to keep his plating tanks in line.

In addition to plating, Progressive also powder coats wheels. It has a Nordson booth where operators manually apply black powder to specific areas of certain wheel designs.

"We do everything from ingot to the finished product," stated Robert Zimmer, vice president of manufacturing. Any design, any style, any finish you could want in an aftermarket wheel, Progressive Custom Wheel makes it. The company's ability to create and finish a variety of designs allows each driver to "customize" his ride.

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