Overview
The abrasion resistance tester is an instrument used to evaluate the wear resistance of coating surfaces, and its working principle is to allow standard abrasives to fall freely to the coating surface at a certain height and flow rate, and quantify the wear resistance of coatings by measuring the amount of abrasive required to wear a certain thickness of coating or achieve a specific wear state. This test method is widely used in the coating industry because of its easy operation and good repeatability, especially suitable for quality control and performance research in the fields of building exterior wall coatings, industrial floor coatings, and wood coatings.
Test principle
The test is based on the erosion and cutting effects of abrasives on the coating surface. Abrasives are usually made of standard quartz sand, and their particle size, shape and hardness must meet the requirements of relevant standards. The abrasive falls vertically from a fixed-height funnel through a catheter at a constant flow rate to the surface of the obliquely placed specimen. Abrasion resistance is typically expressed in terms of the mass (grams) or volume (liters) of the abrasive required for a coating with a unit thickness of wear, such as microns, and is calculated as follows:
Abrasion resistance = V / Δd
where V is the volume of abrasives consumed (liters) and Δd is the thickness of the coating wear (microns). The higher the value, the better the wear resistance of the coating. Key test parameters include abrasive type, sand height, flow rate, specimen tilt angle, and ambient temperature and humidity, all of which need to be strictly followed by standards to ensure comparable results.
Specific applications:
The sand wear resistance test provides important data support for coating research and development, quality inspection and engineering selection. During the R&D phase, the wear resistance of the product can be optimized by comparing the wear resistance data of coatings with different formulations (e.g., resin type, filler type, curing conditions). In production quality control, this test is used to check the consistency of batch products. In engineering applications, test data helps select the right coating product for specific environments such as floors in high-traffic areas, frequently cleaned facades, etc.
Examples of application areas are as follows:
| architectural coatings | Evaluate the resistance of exterior wall coatings to wind and sand erosion |
| Industrial floor coatings | Inspect the friction resistance of vehicle tires and goods on the floor of workshops and warehouses |
| Wood coatings | Test the resistance of floor varnishes or coloured paints to daily walking and mopping abrasion |
| Marine and bridge coatings | Assist in evaluating the performance of protective coatings against environmental particulate erosion |
Relevant standards
A number of domestic and foreign standards have stipulated the sand wear resistance test method, and the coating industry often refers to the following standards. Different standards have detailed differences in sample preparation, abrasive specifications, test procedures and result expression, and should be determined according to the end use of the product or customer requirements when selecting.
| ASTM D968 | The standard test method for testing the wear resistance of organic coatings by the sand falling method |
| ISO 15184 | Colored Paints and Varnishes - Determination of film wear resistance using the sand falling method |
| GB/T 23988 | Determination of wear resistance of coatings Sand falling method |
| JIS K5600-5-7 | General Test Method for Coatings - Abrasion Resistance (Sand Falling Method) |
Notes:
The accuracy and reproducibility of the test results are affected by multiple factors. The uniformity of the abrasives is critical and needs to be screened and replaced regularly. The specimen should be prepared to ensure that the coating thickness is uniform, completely cured and the surface is flat. Ambient temperature and humidity can affect the physical state of some coatings, and condition conditioning and testing under standard conditions are recommended. During operation, ensure that the sand falling duct is vertical and the flow rate is stable, and the multi-point test on the surface of the specimen is averaged. In addition, the test primarily simulates specific types of wear, and the coating may be subjected to more complex composite effects in real-world applications, which need to be interpreted in conjunction with other performance tests.
Conclusion
As an effective testing tool, the sand abrasion tester provides a quantitative means for the coating industry to evaluate the wear resistance of products. Standardized testing provides comparable data to guide product development, quality control, and application selection. Only by understanding its principles, strictly controlling test conditions, and analyzing data in combination with actual application scenarios can we give full play to the role of this instrument in improving the performance and reliability of coating products.
References
ASTM International. ASTM D968 - Standard Test Methods for Abrasion Resistance of Organic Coatings by Falling Abrasive.
International Organization for Standardization. ISO 15184 - Paints and varnishes - Determination of film hardness by pencil test.
National Standardization Administration of China. GB/T 23988 - Determination of abrasion resistance of coatings - Sand falling method.
Japanese Standards Association. JIS K5600-5-7 - Testing methods for paints - Part 5: Mechanical property of film - Section 7: Abrasion resistance (Falling abrasive method).