NALTIC Industrials, LLC

GARDOBOND® C25 (ChromiCoat® L25)

For Boeing Spec BAC 5719 (alodine type) Liquid Chromate Conversion Coating for Aluminum.

A Product of BASF Chemetall US Inc. 
GARDOBOND® C25 (ChromiCoat® L25) is a liquid chromate conversion coating for aluminum.  Applied by immersion or spray.

Primary Application

GARDOBOND® C 25 (ChromiCoat® L25) provides excellent paint adhesion and improved corrosion resistance. GARDOBOND® C25 (ChromiCoat® L25) may be controlled to produce either colorless coatings for use under paint, or rich golden (alodine type) coatings. It is ideally suited for high speed, continuous strip-line operations and is easily metered through automated equipment. For some operations, and particularly high production ones, GARDOBOND C 25/1 (ChromiCoat T3) is recommended for replenishment of GARDOBOND® C25 (ChromiCoat® L25) solutions.

GARDOBOND® C25 (ChromiCoat® L25) meets the following:

Military Specifications: MIL-DTL-81706B, Class 1A and Class 3, Form I (Liquid), Method C (Immersion) and MIL-DTL-5541F.
GARDOBOND® C25 (ChromiCoat® L25) is listed on the Qualified Products List QPL-81706.
GARDOBOND® C25 (ChromiCoat® L25) is also listed on Boeing Process Specification BAC 5719 for Type I (immersion) and Type II (manual application).

 

CHEMICAL CHARACTERISTICS for GARDOBOND C 25 (ChromiCoat L25)

FEATURE

CHARACTERISTIC

Chemical compositionHexavalent chromium, fluoride, nitric acid, accelerators
Physical formDark (alodine) brown liquid
OdorAcrid
Specific gravity1.142 g/mL at 20 °C (68 °F)
Bulk density9.5 pounds/gallon at 20 °C (68 °F)
viscosity2 – 6 cps, Brookfield Spindle 1, 60 rpm
Foaming tendencyNone
Flash pointNone
behavior in hard waterNot recommended
RinsabilityGood
Biodegradablenot applicable, non-surfactant material
Phosphorous-freeYes
Regular working concentrations0.5 to 5% by volume
Regular working temperatures80 – 120 °F (27 – 49 °C)
pH at working concentrations1.6 – 2.0

Approvals:

GARDOBOND C 25 (ChromiCoat L25) meets the following: Military Specifications: MIL-DTL-81706B, Class 1A and Class 3, Form I (Liquid), Method C (Immersion) and MIL-DTL-5541F.

GARDOBOND C 25 (ChromiCoat L25) is listed on the Qualified Products List QPL-81706.

GARDOBOND C 25 (ChromiCoat L25) is also listed on Boeing Process Specification BAC 5719 for Type I (immersion) and Type II (manual application).

Application Procedure:

Operating temperatures and working concentrations for applying Oakite ChromiCoat L25 are largely determined by the type of coating desired and the application method employed.

Preparing the Solution: Use only deionized or reverse osmosis water. Hard water salts diminishes GARDOBOND C 25 (ChromiCoat L25) performance by complexing active ingredients, preventing optimum pH reducing the coating’s corrosion resistance. Therefore, deionized (DI) or reverse osmosis (RO) water should be used.

Applying GARDOBOND C 25 (ChromiCoat L25) on Aluminum by Immersion, for general applications:
1. Remove organic soils with an alkaline cleaner.
2. Rinse in cold running water; two separate rinses are desirable.
3. If necessary for oxide removal or for finished part appearance, etch in a Chemetall Oakite product such as Etchant A45.
4. Rinse in cold running water; two separate rinses are desirable.
5. If necessary, desmut in a Chemetall Oakite deoxidizer.
6. Rinse in cold running water; two separate rinses are desirable.
7. Immerse in a solution of Oakite ChromiCoat L25. Concentrations, temperatures, and immersion times are listed below according to the type of coating desired.

  • For standard color coatings (25 to 80 mg/ft2): use a concentration of 3% to 5% by volume, between 90 and 110 °F (32 – 43 °C) for 1 to 3 minutes at a pH range of 1.6 to 1.8.
  • For lightweight color coatings (15 to 25 mg/ft2): use a concentration of 1.5% to 3% by volume, between 80 and 100 °F (27- 38 °C) for 20 to 30 seconds at a pH of 1.6 to 1.8.
  • For colorless coatings (5 to 15 mg/ft2): use a concentration of 1/2 to 1% by volume, between 80 and 100 °F (27 – 38 °C) for 10 to 25 seconds at a pH range of 1.6 to 2.0. 

8. Rinse in cold running water; two separate rinses are desirable.
9. Dry at 140 °F (60 °C) maximum.

Applying GARDOBOND C 25 (ChromiCoat L25) on Aluminum by Immersion, for MIL-DTL-5541F, class 1A:
1. Clean with a non-etch alkaline detergent such as Oakite 61 B.
2. Rinse in 2 separate cold running water rinses.
3. GARDOBOND C 25 (ChromiCoat L25) at 3 – 5% by volume, between 90 and 100 °F (32 – 43 °C) for 3 minutes at a pH of 1.6 to 1.8.
4. Rinse in 2 separate cold running water rinses.
5. Dry at 140 °F (60 °C) maximum.
Process Technologies Tank Heater and Accessories Pricing

IMPORTANT
Avoid using etch or deoxidizer for aluminum alloy 2024T3 when meeting MIL-DTL-5541F coating applications. Yet if oxides must be removed, we recommend the chromium-based Oakite Deoxidizer 34L.

Applying GARDOBOND C 25 (ChromiCoat L25) in accordance with MIL-C-5541, Class 3, Form 1, Method C:
1. Clean with a non-etch alkaline detergent such as Oakite 61 B.
2. Rinse in 2 separate cold running water rinses.
3. Deoxidize with Deoxidizer 34L, 10% by volume, between 65 and 75 °F (18 – 24 °C), 2 minutes.
4. Rinse in 2 separate cold running water rinses.
5. GARDOBOND C 25 (ChromiCoat L25) at 2 – 3% by volume between 75 and 85°F (24 – 29 °C) for 15 seconds at a pH of 1.6 to 2.0.
6. Rinse in 2 separate cold running water rinses.
7. Dry at 140 °F (60 °C) maximum.

Solution Control: GARDOBOND C 25 (ChromiCoat L25) is controlled using Gardotest Procedure 137.
Sample Size: 5.0 mL              Factor: 0.56

Determine Fluoride Content:
For a nominal fee, send samples of solution to determine fluoride content to NALTIC Industrials’ lab.

Fluoride content may also be monitored using Gardotest Procedure 152. The bath pH is controlled with a calibrated pH meter. The probe should be calibrated with 2.0 and 4.0 buffer and contact with the GARDOBOND C 25 (ChromiCoat L25) should be limited for long probe life.

Replenishment
Concentration: For most applications, GARDOBOND C 25 (ChromiCoat L25) baths may be replenished with GARDOBOND C 25 (ChromiCoat L25). In applications with a high amount of surface area processed, with minimal drag-out, it may instead be necessary to replenish with GARDOBOND C 25/1 (ChromiCoat T3), which has a lower pH and higher fluoride content.

pH adjustment
If the pH of the GARDOBOND C 25 (ChromiCoat L25) bath rises above the 1.8 to 2.0 maximum, add 2.5 pint/100 gallons (350 mL/100 liters) of Gardobond Additive H 7140/1 to reduce the pH by 0.2 – 0.4 units. If the pH of the GARDOBOND C 25 (ChromiCoat L25) bath falls below 1.6, the pH may be increased with additions of Gardobond Additive H 7212 which is diluted 1:10 with DI or RO water. Add slowly with good mixing.

Equipment
The Chemetall Electrodeless Conductivity/Concentration Control System and Chemical Metering Pump can be used to monitor and automatically maintain the concentration of this product using conductivity. Please contact the Chemetall Process Equipment and Engineering Department for specific recommendations.

Other Important Considerations and Reminders
1. The quality of the water used to prepare solutions has an important influence on the quality of the final GARDOBOND C 25 (ChromiCoat L25) coating. For best results, deionized (DI) or reverse osmosis (RO) water is preferred for bath make-up, replenishment, and final rinsing.
2. Where extrusions are processed, a non-silicated alkaline detergent may be required.
4. The quality of the GARDOBOND C 25 (ChromiCoat L25) coating is largely influenced by concentration, pH, time, temperature, and bath agitation.
5. Cold water must be used when rinsing.
6. Coatings are relatively hard when dry but may be damaged if brushed or wiped while still wet.
7. Stainless steel alloy 316L or polypropylene tanks are recommended. Heaters should be constructed of alloy 316L.
8. Keep the concentrate as well as solutions of GARDOBOND C 25 (ChromiCoat L25) away from combustible, organic, or readily oxidizable materials. Avoid contact or mixing with chlorine-releasing materials.
9. Avoid the introduction of steel or ferrous alloys to the working solution.
10. GARDOBOND C 25 (ChromiCoat L25) baths are more active when made up fresh. It’s recommended to operate at the low end of the operating ranges (lower concentration, lower temperature, shorter time) with a fresh bath.

TRANSPORTATION for US DOT container size 55 gal 528 lbs.  (Also available in 4 Gallon Pail 41 lbs.)
· ADR/RID class: 8 Corrosive Liquid, Acidic, Inorganic N.O.S.
· NMFC: 44155 S3
· UN-Number: 3264
· Packaging group: II
· Hazard label 8
· Description of goods: Chromic Acid Solution

Safety and Handling:

Prior to handling and use of Chemetall products see the Safety Data Sheet/ This should be read and understood by all personnel in contact with the product.

KEEP OUT OF REACH OF CHILDREN

Disposal:

Any disposal of Chemetall products should be in accordance with all applicable federal, state, and local regulations.

The process solution can contain components other than those present in the product as supplied. Analysis of the process solution may be required prior to disposal.

Storage:

Indoor storage at temperatures between 40 °F and 100 °F is recommended. All containers should be tightly closed when not in use.

SUGGESTION OF OTHER PRODUCTS YOUR COMPANY MAY USE

• CLEANERS
• ETCHANTS
• DEOXIDIZERS
• RUST PREVENTIVES
• METALWORKING FLUIDS (coolants and lubricants)
• WASTE WATER TREATMENT CHEMICALS
• FLOOR CLEANERS AND MAINTENANCE PRODUCTS
• PROCESS EQUIPMENT/CONTROL SYSTEMS

DISTRIBUTED BY NALTIC INDUSTRIALS AN AUTHORIZED DISTRIBUTOR FOR THE USA

Chemetall US, Inc. (“Chemetall”) warrants that products described within its official technical papers will conform with its published specifications. The products supplied by Chemetall and information related to them are intended for use by buyers having necessary industrial skill and knowledge. Buyers should undertake sufficient verification and testing to determine the suitability of the Chemetall materials for their own purpose. Since buyer’s conditions of use of products are beyond Chemetall’s control, Chemetall does not warrant any recommendations and information for the use of such products.

CHEMETALL DISCLAIMS ALL OTHER WARRANTIES INCLUDING THE IMPLIED WARRANTY OF MERCHANTABILITY AND FITNESS FOR ANY PARTICULAR PURPOSE IN CONNECTION WITH THE USE OF ITS PRODUCTS.

Please contact us directly for a complete and official Chemetall Technical Data Sheet and/or MSDS in PDF. 
Contact us: Office (888) 891-0077
email: 411@naltic.com

Headquarters
NALTIC Industrials, LLC
299 S Main St Suite 1300
Salt Lake City, UT 84111
USA