The standard “ISO 10289 Corrosion test methods for metallic and other inorganic coatings on metallic surfaces - Evaluation of test specimens and manufactured products subjected to corrosion testing”, developed by the International Organization for Standardization (ISO), describes the method for evaluating the condition of decorative and protective metallic and inorganic coated panels or articles exposed to corrosive environments for testing or other purposes.
This standard applies to test panels or components exposed to natural atmospheres, moving or static conditions, or subjected to accelerated testing.
This standard acknowledges that the degree of protection can be objectively assessed in accordance with this standard. However, the assessment of appearance depends on many subjective factors.
The edges of test panels or components may be protected with, for example, tape or wax (paraffin), provided that this is an accepted part of the test and is stated in the test report. This is required if the samples are cut from larger pieces and the uncoated edges are exposed.
This International Standard establishes a grading system for evaluating the deterioration of coatings and the base metal due to corrosion. The grading method described herein is applied to assess the appearance of the coating and the degree of corrosion on the critical surfaces of components subjected to performance testing.
The result of inspecting a surface is called a performance rating and is recorded as two separate ratings: a protection rating and an appearance rating.
When recording a surface rating, the types and severity of defects contributing to the rating must be specified, if this information is required. This information is recorded using accepted symbols for defects and their degree. Where only a protection rating is required, the appearance rating may be omitted.
Defects can affect both the degree of protection and the degree of appearance. In this rating system, the degree of protection is a simple numerical rating, while the degree of appearance may include specific defects along with a numerical rating indicating intensity. The table entitled "Protection and appearance ratings" given in the standard contains a list of defects.
Defects include crater corrosion, pinhole corrosion, general coating corrosion, corrosion products, bubbles, and all other defects affecting the coating. Some defects, such as bubbles, can occur between the coating, the base metal, the interface between the coating and the base metal, or between layers in the coating.
Other defects may contain minor corrosion but can have a significant impact on appearance, such as staining, discoloration, and cracks.
Defects on the base metal surface, such as scratches, porosity, non-conductive inclusions, rolling and mold marks, cold joints, and cracks, can negatively affect the performance of applied coatings, even when best surface treatment practices are followed. Such defects should be reported and graded separately.
Defects resulting from exposure, such as peeling or flaking of the coating, should be noted, as this indicates improper preparation of the base metal or incorrect application of the coating.
In short, the ISO 10289 standard provides a standardized method for evaluating and grading the condition of decorative and protective metallic and other inorganic coatings applied to metallic surfaces after exposure to corrosive environments. This method is valid if the exposure occurs in the following ways:
This standard focuses on evaluating test panels, test specimens, or actual manufactured products (components/products) that have been subjected to corrosion testing or real-world service. The evaluation acknowledges that coatings may behave differently depending on the base metal:
Two separate, related ratings are assigned:
The types of defects considered under this standard include: pitting, rusting/base metal corrosion, blistering, cracking, peeling, and staining.
The inspection method is visual examination, usually performed at specific distances or under controlled lighting. Sometimes it is supported by magnification or other aids.
A numerical scale of 0-10 is typically used as a rating system. Here, 10 represents no defects/excellent condition, while lower numbers indicate increasing severity.
Point diagrams, tables, and color photographs are used to help assign ratings objectively.
These standard appendices contain separate guidelines for cathodic and anodic coatings:
The test report includes details of the coating, exposure conditions, rating values, photographs or drawings if necessary, and any observations.
This standard provides comparable and repeatable results when different laboratories, manufacturers, or quality departments evaluate corrosion performance. It is commonly applied in the following sectors:
This standard complements existing corrosion testing methods (e.g., ISO 9227 salt spray and ISO 16701 cyclic corrosion) by providing a common language and criteria for evaluating the results of these tests.
Without a common grading method, different laboratories, manufacturers, suppliers, or customers could interpret the same corroded test piece very differently, leading to disputes, inconsistent quality claims, or unreliable product comparisons. This standard solves this by defining clear, numerical criteria that everyone uses in the same way.
This standard is considered important because it separates two critical aspects of performance:
This distinction is important because some coatings (such as cathodic coatings like chrome on steel) are excellent at maintaining appearance until they are damaged but offer very little protection, while anodic coatings (such as zinc on steel) sacrifice themselves to protect the substrate but may deteriorate more quickly.
For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the ISO 10289 standard.
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