MAR Chrome Pro DOS

MAR Chrome Pro DOS is a specially formulated High Speed Decorative Chromium electroplating process which is a custom blend of the secondary organic type of catalyst with Chromic Acid. This high-speed capability is a function of the chemistry design, which allows higher cathode current efficiencies.

The electroplated deposits from the MAR CHROME PRO DOS system exhibits a very shiny, bright and smooth surface at a large range of current densities. The operating plating current density range will vary with applications; however, the normal plating range varies from 50 to 300 amps/ft2.

The MAR CHROME PRO DOS plating system is maintained with a liquid additive MAR CHROME PRO DOS-L which eliminates dusting and splash back from solid additions. The system consistency can be maintained using an amp-hour control system. Standard pretreatment cycles, anodes and equipment can be used as those in any hexavalent chromium plating systems.

A solid version, MAR CHROME PRO DOS-S of this system, is also available to minimize the transportation of water over a large distance. It contains all of the active components to maintain the working solution at optimum operating chemical parameters.

WARRANTY AND DISCLAIMER: This information is based on our experience and is, to the best of our knowledge, true and accurate. MAR-Tech Holdings Inc. gives no warranty, expressed or implied and the products are sold upon condition that the purchasers will make their own tests to determine the quality and suitability of the product. Any information or suggestions are given without warranty of any kind and the purchasers are solely responsible any loss arising from the use of such information.

Recommended Operating Parameters


Chromic Acid 32 oz/USG (240 g/litre) 20 – 50 OPG (150-375 g/l)
Sulphate radical 0.16 oz/USG (1.2 g/litre) 0.05 – 0.25 OPG (0.4 – 2 g/l)
Ratio 200:1 125 - 300
Temperature 110°F (43°C) 100oF – 125°F (38°C-52°C)
Cathode Current Density Range 150 ASF 50 – 300 ASF
Plating Solution Make-up and Conversions

Existing Chromium Solution Conversion

Most conventional decorative plating solutions can be converted to the MAR CHROME PRO DOS. An analysis of the impurities must be done to determine the level of metallic contamination prior to conversion.

New Plating Solution Make-up

A new make-up can be accomplished by two methods. The use of MAR CHROME PRO DOS-M can be used. This liquid contains 480 g/litre of Chromic Acid and the required amount of MAR DOS CAT secondary catalyst. The second method of make-up would be the use of solid MAR CHROME PRO DOS-S which contains the correct amount of the secondary catalyst.


  1. For each 100 Litres of plating solution: 12 litres of MAR CHROME PRO DOS-M
  2. For each 100 USG of plating solution: 12 USG of MAR CHROME PRO DOS-M

Dilute to volume with DI water.


Add DI water to ½ the volume

  1. For each 100 litres of plating solution: 24 Kg of MAR CHROME PRO DOS-S
  2. For each 100 USG of plating solution: 200 Lbs. of MAR CHROME PRO DOS-S

Bring the solution to the correct level with DI Water.

Heat the solution to the operating temperature of 100oF (38°C). At this time analyze the plating solution of sulphate. Add Sulphuric Acid to bring the sulphate content to 0.16 oz/USG (1.2 g/l) if required. Electrolyze the plating solution for 1 hours to form an equilibrium with all of the components.


The MAR CHROME PRO DOS plating solution can be maintained using the liquid MAR CHROME PRO DOS-RL or the solid MAR CHROME PRO DOS-RS. Both systems contain Chromic Acid and the Organic type secondary catalyst. The sulphate catalyst is monitored by analysis and adjustments are made with Sulphuric acid or Barium Carbonate if required.

The liquid MAR CHROME PRO DOS-RL contains 480 g/l of Chromic Acid and the secondary organic type catalyst. Additions can be made at a rate of 350 ml per 1,000 amp-hours using an amp-hour controller with a feeder pump. Compensation for drag-out must be considered and added to the feed rate.

The solid MAR CHROME PRO DOS-RS contains the Chromic Acid and the secondary organic type catalyst and can be added to the plating solution at a rate of 15 KG per 100,00 amp-hours or by analysis of the Chromic Acid in the plating solution. Compensation for drag-out must be considered and added to the feed rate.



Steel tanks lined with PVDF, PFA or flexible PVC materials or other materials capable of withstanding the continuous exposure to the high concentration of Chromic Acid and temperature.


Standard 7% tin – 93% lead anodes should be used. A combination of tin, antimony and lead alloys may be also used.


Appropriate rectifiers with less than 5% ripple and sufficient amperage and voltage capacity should be used.


Titanium or TEFLON® covered heaters, heating and cooling coils and heat exchangers can be used. Steel or Stainless Steels must be avoided since they will dissolve in the chromic acid solution.


Ventilation that meets government emission standards should be used. Temperature controls and bus bars used in conventional chromium plating systems can be used. If heating is done using steam and cooling by water, electrically insulate these lines by using rubber connections.


All of the MAR CHROME PRO DOS compounds and the actual plating bath contain Chromic Acid. It can cause severe burns. Avoid contact with eyes, skin, and clothing. Do not inhale or swallow. Eye contact can cause severe burns or loss of sight. Use with adequate ventilation and proper protective equipment. Rubber gloves and chemical safety glasses are recommended safety equipment including NIOSH/MSHA approved respirators should be used, as necessary. Do not eat or drink while handling this product, and wash thoroughly after handling these materials. Consult the individual Material Safety Data Sheets (MSDS) of the MAR CHROME PRO DOS system for complete information.


Eye contact: Flush immediately with a continuous flow of warm water for 15 minutes. Call a physician for treatment for exposure to Chromic Acid immediately.

Skin contact: Flush thoroughly with water. Contaminated clothing must be removed and washed immediately before reuse. Chromic Acid in contact with organic materials, such as clothing will cause burns.

Inhalation: Remove the exposed patient to fresh air and consult a physician.

Ingestion: HARMFUL IF SWALLOWED. If swallowed, DO NOT INDUCE VOMITING. Give large quantities of water. Never give anything by mouth to an unconscious person. Call a physician for further treatment immediately.


The MAR CHROME PRO DOS-RL liquid is very stable, however, the solid MAR CHROME PRO DOS-RS can absorb moisture once the container has been opened. Storage between 10°C and 40°C is preferred. Prolonged storage at low temperature may cause solids to crystallize out of solution. Do not store in contact with organic or alkaline materials. Keep containers closed when not in use. Do not cross contaminate containers; always use clean scoops, buckets, and pumps.


Consult the MSDS’s for the MAR CHROME PRO DOS plating system for complete information.

Always contain the spillage, soak up the solutions with an inert absorbent and never use paper. Scoop into a suitable container for disposal. Refer to the applicable provincial and local regulations for the current response information.

The waste generated from any spill of the MAR CHROME PRO DOS products and the plating solution will contain levels of chromium in excess of permissible limits. Refer to your local and government regulations. These laws and regulations will determine the proper procedure for waste disposal.

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