ASTM B380 Standard Test Method for Corrosion Testing of Decorative Electrodeposited Coatings by the Corrodkote Procedure

The ASTM B380 standard, in conjunction with the industry-accepted salt spray test standard ASTM B117, provides manufacturers with essential guidelines for corrosion testing of decorative electrodeposited coatings. By adhering to these standards and utilizing reliable testing methods, manufacturers can ensure their coatings meet the required corrosion resistance standards. Corrosion testing plays a vital role in ensuring the durability and quality of decorative electrodeposited coatings.

The ASTM B380 standard provides guidelines for conducting corrosion tests using the Corrodkote procedure. Incorporating these procedures and tests can ultimately lead to the production of more durable and reliable coatings that can withstand harsh environmental conditions. The test method outlined in this study involves the application of a slurry containing corrosive salts onto test specimens. The slurry is allowed to dry on the surfaces of the specimens before they are exposed to a high relative humidity for a specific duration. This procedure aims to evaluate the resistance of the coated specimens to corrosion under simulated environmental conditions.

The salt spray test is a commonly used method to evaluate the corrosion resistance of coatings. By subjecting the specimens to both the corrosive slurry and elevated humidity, this test provides a comprehensive examination of their durability and performance. The results obtained from this method can aid in the assessment and comparison of different protective coatings or materials, enabling researchers and engineers to make informed decisions regarding their suitability for various applications.

ASTM B380 Standard Test Method for Corrosion Testing of Decorative Electrodeposited Coatings by the Corrodkote Procedure
Type and Description WEW-YW-60D WEW-YW-90D WEW-YW-110D WEW-YW-120D WEW-YW-130D WEW-YW-160D WEW-YW-200D
Inner Dimension(mm) 600*450*400 900*600*500 1000*750*500 1200*800*500 1300*850*600 1600*1000*600 2000*1000*600
Outer Dimension(mm) 1070*600*1180 1410*880*1280 1600*1050*1200 1700*1150*1200 1800*1200*1300 2300*1250*1450 2800*1350*1450
Test Room Size (Liters) 108 Liters 270 Liters 420 Liters 500 Liters 650 Liters 1000 Liters 1200 Liters
Power Supply AC 220V, 50Hz AC 220V, 50Hz AC 220V, 50Hz AC 220V, 50Hz AC 220V, 50Hz AC 380V, 50Hz AC 380V, 50Hz
Power Current 1Phase, 1.5 kW 1Phase, 2.0 kW 1Phase, 2.5 kW 1Phase, 2.9 kW 1Phase, 3.5 kW 3Phase, 5.0 kW 3Phase, 6.5 kW
Lid Opening Method Manual Opening Manual Opening Manual Opening Manual Opening Pneumatic Air-Operated Pneumatic
Brine Tank Volume 15 Literes 25 Literes 30 Literes 30 Literes 35 Literes 40 Literes 45 Literes
Test Room Temp Range Ambient Temperature +5℃ – +30℃, Ventilation is recommended, if the temperature exceeds +30℃, it is recommended to adjust the room temperature by suitable means. Ambient humidity should be controlled below 80%RH.
Test Room Temp Range RT+10℃ – +55℃ RT+10℃ – +58℃ RT+10℃ – +55℃ RT+10℃ – +58℃ RT+10℃ – +55℃ RT+10℃ – +58℃ RT+10℃ – +55℃
Saturated Barrel  RT+10℃ – +70℃ (Purpose: Heating and filtering of compressed air to reduce nozzle crystallisation.)
Temp Performance Temperature Uniformity: ≤2℃ Temperature Fluctuation: ≤ ±0.5°C Temperature Uniformity: ≤2℃ Temperature Fluctuation: ≤ ±0.5°C Temperature Uniformity: ≤2℃ Temperature Fluctuation: ≤ ±0.5°C Temperature Uniformity: ≤2℃
Salt Mist Settling Rate 1~2 ml/80 cm2/h (Take 16 Hours To Test The Average Value) 1~2 ml/80 cm2/h 1~2 ml/80 cm2/h (Take 16 Hours To Test The Average Value)
Spray Method Continuous, Intermittent,  Programmable Tests Continuous, Intermittent,  Continuous, Intermittent,  Programmable Tests Continuous, Intermittent,  Continuous, Intermittent, 
Safety Devices Low Water Level Alarm Over-Temperature Alarm (Mechanical Over-Temperature Protection + Electronic Over-Temperature Protection Double Over-Temperature Protection) Low Air Pressure Alarm
Air Requirements Inlet Pressure Above 0.4Mp. Two-Stage Pressure Regulation. Spray Pressure 0.07~0.17mp (Adjustable) Inlet Pressure Above 0.4Mp. Two-Stage Pressure Regulation. Spray Pressure 0.07~0.17mp (Adjustable) Inlet Pressure Above 0.4Mp.
Sample Holder One Set Each Of V-Groove And O-Round Bar (Combined To Form An Angle Of 20°±5%). Special Samples Support Customisation. Load Capacity According To The Actual Situation
Standard Configuration 1 Set Of V-Type/O-Type Shelves, 2 Bottles Of Test Drug Sodium Chloride (500g/Bottle), 1 Plastic Anti-Rust Bucket (5l Capacity), 1 Nozzle

ASTM B117 is the established salt spray test standard developed by the American Society for Testing and Materials (ASTM). It outlines the procedures, test conditions, and evaluation criteria for conducting salt spray tests. By subjecting coated samples to a controlled saltwater mist environment, this test simulates the harsh conditions coatings may face in real-world applications.

Salt spray testing, as per ASTM B117 and other standards, remains a crucial method to determine the durability and resistance of coatings in the face of corrosion. It simulates the corrosive effects that can occur over an extended period, helping manufacturers identify potential weaknesses and improve coating formulations. This testing method allows for better product development, ensuring coatings can withstand harsh conditions and prolong the lifespan of various substrates.

To effectively conduct salt fog testing, a salt mist test chamber is essential. These chambers create a controlled environment to expose specimens to a continuous mist of saltwater. The chamber maintains the required temperature, humidity, and concentration of saltwater solution, offering precise and repeatable testing conditions. Salt mist test chambers are crucial for evaluating the reliability and quality of coatings facing corrosive environments.

salt spray testing
5.1 The apparatus shall consist of a humidity chamber, specimen supports, provision for heating the chamber, and provisions for air circulation in the chamber. 5. Apparatus
5.2 Drops of moisture that might accumulate on the ceiling or cover of the chamber of specimen supports shall not be permitted to fall on the specimens being tested.
Note 2: Suitable apparatus may be constructed from salt-spray equip- ment by eliminating fog-spray nozzles, substituting water for the salt solution in the reservoir, adding a manifold for bubbling air through the water in the reservoir, and adding a fan for circulating the air in the chamber with the fan discharge directed across the surface of the water in the reservoir.
5.3 Materials of construction shall not affect the corrosiveness of the test.
6.1 Corrodkote Slurry: Prepare the Corrodkote slurry in a glass beaker by dissolving 0.035 g of reagent grade cupric nitrate (Cu(NO 3 ) 2 ·3H 2 O), 0.165 g ofACS reagent grade ferric chloride (FeCl 3 ·6H 2 O), and 1.0 g of ACS reagent grade ammonium chloride (NH 4 Cl) in 50 mL of water conforming to Specification D1193, Type IV. Stir 30 g of water-washed, ceramic-grade kaolin into the solution. Mix the slurry thor- oughly and allow it to stand for about 2 min so that the kaolin will become saturated. Mix the slurry thoroughly just before using. 6. Procedure
6.1.1 An alternative method of preparing the Corrodkote slurry is as follows. Weigh out 2.5 g of cupric nitrate (Cu(NO 3 ) 2 ·3H 2 O), and dissolve and dilute with distilled water in a volumetric flask to exactly 500 mL. Weigh out 2.50 g of ferric chloride (FeCl 3 ·6H 2 O), and dissolve and dilute with distilled water in a second volumetric flask to exactly 500 mL. (The ferric chloride solution shall be kept in a dark place and stoppered with a rubber or glass stopper when not in use.) (The ferric chloride solution shall not be more than 2 weeks old, since older solutions become unstable.) Weigh out 50.0 g of ammonium chloride (NH 4 Cl) and dissolve and dilute with distilled water in a volumetric flask to exactly 500 mL. Then measure out exactly 7.0 mL of the cupric nitrate solution, 33.0 mL of ferric chloride solution, and 10.0 mL of the ammonium chloride solution; place these in a beaker to which 30.0 g of kaolin is now added. Stir with a glass stirring rod.
6.2 Test Specimens: The type and number oftest specimens to be used, as well as the criteria for evaluation of the test results, shall be defined in the specifications covering the material or product being tested, or shall be mutually agreed upon by the manufacturer and the purchaser.
6.3 Preparation ofTest Specimens:  Metallic and metallic- coated specimens may be solvent cleaned before testing, using a suitable solvent such as alcohol, ethyl ether, acetone or petroleum ether. Solvents that are corrosive or will deposit protective films shall not be used.
6.4 Slurry Application: Apply the Corrodkote slurry to the specimen using a clean paint brush. Dip the brush in the Corrodkote slurry and with a circular motion, completely cover the specimen. Then smooth out the coating by brushing lightly in one direction. Allow the specimens to dry at room temperature and at a relative humidity less than 50 % for 1 h before placing them in the humidity chamber. Should it be desirable to cut test specimens from parts or from preplated, or otherwise coated steel sheet, the cut edges shall be protected by coating them with paint, wax, tape, or other effective media so that the development of a galvanic effect between such edges and the adjacent plated or otherwise coated-metal surfaces, is prevented.
6.5 Position ofSpecimens During Test:  The position of the specimens in the humidity chamber during the test is not critical as long as they do not touch each other and the supports do not touch the test areas that have been coated with the Corrodkote slurry.
6.6 Conditions in the Humidity Chamber:  The exposure zone ofthe humidity chamber shall be maintained at 38 6 2°C.
The relative humidity of the exposure zone of the chamber shall be maintained between 80 and 90 % shall not produce condensation on any of the parts.
Note 3: A fan or blower may be used in the chamber to maintain uniform temperature and humidity. The amount of air circulation in the chamber necessary to maintain these conditions must be determined for each chamber. An Abbeon certified hygrometer Model No. 167, or its equivalent 4 is a suitable instrument for measuring the relative humidity of the exposure zone of the humidity chamber.
6.7 Test Cycle: Exposure in the humidity chamber shall be continuous for periods up to 20 h. A single test period up to 20 h shall be considered as one cycle. Continuous operation implies that the humidity chamber be closed and operated continuously except for the short interruptions necessary to place or remove test specimens. Operations shall be so scheduled that these interruptions are held to a minimum. When more than one test cycle of 20 h or less is specified, the test specimen shall be treated as outlined in 6.9 after each test cycle. Fresh slurry shall be applied for each succeeding cycle. After the last test cycle, the test specimen shall be treated as outlined in 6.9.
6.8 Period ofTest: The period of each test cycle as well as the number of test cycles required, shall be as specified in the specifications for the material or product being tested, or as mutually agreed upon between the manufacturer and the purchaser.
6.9 Cleaning of Testing Specimens:  Treat the specimen after each test cycle as outlined in 6.9.1. After the last test cycle and if the specimen is to be inspected between test cycles, treat the specimens as outlined in 6.9.1 and 6.9.2.
6.9.1 Remove the specimen from the humidity chamber. Clean the specimen using fresh running water and a piece of clean cheesecloth or suitable synthetic sponge to remove all of the slurry. A mild abrasive such as a water paste of tripoli may be used to remove any adhering materials.
6.9.2 Since the cleaning operation described in 6.9.1 will remove any corrosion products, it will be necessary to rede- velop the points of failure. This may be done in several ways, such as exposure for 4 h in the salt spray cabinet described in Practice B117, exposure for 24 h in a humidity cabinet operated at 38°C and 100 % relative humidity with condensation, or some other method that will cause corrosion of the basis metal without any significant damage to the coating.
Note 4: Corrosion products visible on the test specimen with the slurry in place are not necessarily caused by points of failure in the coating. Particles of metal accidentally deposited on the test specimen before humidity exposure will also cause visible corrosion products.
salt spray fog apparatus
Corrosion testing methods are designed to assess the ability of coatings to withstand various corrosive environments. The suitability of a specific method depends on the coating type, intended application, and industry standards. Apart from the salt spray test, other prominent corrosion testing methods include the cyclic corrosion test, humidity test, and salt fog test. Corrosion Testing Methods
The salt fog test, also known as salt mist testing, is a subset of corrosion testing methods. It involves subjecting coated samples to an atomized saltwater fog, replicating the corrosive effects of coastal or marine environments. ASTM B117 provides detailed instructions on test parameters, sample preparation, and evaluation criteria, ensuring consistent and reliable results. This test is particularly useful for coatings applied in industries exposed to salt-laden atmospheres. Salt Fog Testing (ASTM B117)
ASTM B380 complements the salt spray test and provides specific guidelines for corrosion testing of decorative electrodeposited coatings using the Corrodkote procedure. By following these procedures, manufacturers can ensure that their products meet the required corrosion resistance standards. The ASTM B380 standard includes the preparation of test specimens, test conditions, and assessments to determine the severity of corrosion. ASTM Corrosion Testing

Nickel/chromium and copper/nickel/chromium electrodeposited coatings are highly sought after for their excellent decorative and protective properties, finding extensive applications in various industries. These coatings not only enhance the aesthetic appeal of objects but also provide an effective barrier against corrosion and wear. To ensure the consistent quality of electroplated articles, the Corrodkote test assumes a vital role in both manufacturing control and research and development.

By subjecting the coatings to the Corrodkote test, manufacturers can evaluate the corrosion resistance and durability of their electroplated products. This test serves as a standard method to ascertain the ability of the coatings to withstand harsh environmental conditions, such as exposure to moisture, chemicals, and salt sprays. Manufacturers can use the results of the Corrodkote test to monitor and refine their electroplating processes, ensuring that the finished articles meet the desired standards of quality, longevity, and performance.

Furthermore, the Corrodkote test is invaluable in the realm of research and development. It allows scientists and engineers to analyze and compare the corrosion resistance of different electrodeposited coatings under controlled conditions, aiding in the formulation of innovative plating techniques and the development of novel coating compositions. By investigating the performance of various electroplated coatings through the Corrodkote test, researchers can push the boundaries of electroplating technology, leading to advancements that enhance protection, aesthetics, and functionality.

7.1 After redevelopment of points of failure, as outlined in 6.9.2, make a careful and immediate examination for the extent of corrosion of the test specimen or for other failures as required in the specifications covering the material or product being tested or by agreement between the manufacturer and the purchaser. 7. Evaluation of Results
8.1 The report shall contain the following information, unless otherwise prescribed in the specifications covering the material or product being tested: 8. Report
8.1.1 The title, designation, and year ofissue ofthis method,
8.1.2 Readings of temperature within the exposure zone of the humidity chamber,
8.1.3 Readings of relative humidity within the exposure zone of the chamber,
8.1.4 Type of specimen and its dimensions or number, or description of part,
8.1.5 Exposure period for each cycle and number of cycles,
8.1.6 Results of all inspections, and
8.1.7 Method of redeveloping corrosion spots.
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