Methods for determining the thickness of the galvanized coating include a variety of precise measuring techniques and instruments to ensure that the quality of the galvanized coating meets the standards. The environmental requirements of the laboratory must be strict to avoid external interference affecting the test results. The laboratory room should have stable temperature and humidity control and appropriate space layout to ensure the accuracy and repeatability of the test. Overall, the correct assay method and a standardized laboratory environment are key factors in ensuring the quality of the galvanized coating.
1. Determination method of galvanized layer thickness
The non-destructive method is used to determine the thickness of the galvanized layer.
Magnetic method: Thickness measurement using the influence of magnetic materials on magnetic fields. The advantages are simple operation, fast speed, suitable for iron-based substrates; The disadvantage is that it is not suitable for non-magnetic materials.
Eddy current method: Thickness is measured by detecting changes caused by eddy currents in the galvanized layer. The advantage is that it is suitable for non-magnetic materials and has high precision; The disadvantage is that it is sensitive to thin coatings.
X-ray fluorescence: X-rays are used to excite the elements in the galvanized layer and measure the fluorescence intensity of their emission to determine the thickness. The advantage is that it is suitable for a variety of substrates; The disadvantage is the high cost of equipment.
Ultrasonic: Thickness is measured by the difference in the propagation velocity of ultrasonic waves in the coating and the substrate. The advantage is that it is suitable for a variety of substrates and has a large detection depth; The disadvantage is that it is affected by the surface roughness.
Destruction Law：
Weighing method – the thickness is calculated by measuring the mass and area of the galvanized layer. The advantage is high accuracy; The downside is that the operation is destructive.
Metallurgical microscopy – direct measurement of coating thickness by microscopic observation of the cross-section of the cut sample. The advantage is that it is intuitive and precise; The disadvantage is that the operation is complex and requires sample pretreatment.
Second, the requirements of the laboratory for the use of space
Type of laboratory
Chemistry laboratories – ensure adequate water supply and drainage, single-phase and three-phase power supplies, exhaust facilities and acid and alkali corrosion-resistant test benches. If possible, piped gas can be installed.
Precision instrument room - fireproof, moisture-proof, shock-proof, dust-proof, maintain stable temperature (18-25°C) and humidity (60%-70%). The ground should be terrazzo or anti-static ground, and the equipment should have a special ground wire. Equipped with exhaust hood and fire prevention facilities, cylinders should be stored in a special room.
Auxiliary room - such as the drug storage room should be fireproof and explosion-proof, and use explosion-proof lamps, suitable for storing a small amount of medicines.
Lab prerequisites
Organizational management and quality management system: Covering technical data management, equipment maintenance, sample management, etc.
Instrument and equipment requirements: It needs to be checked and calibrated regularly, and the fault should be repaired in time.
Laboratory environmentThe environment should be clean and tidy, and the equipment layout should be convenient for experiments and maintenance.
Test Method Requirements: Method steps should be documented and evaluated.
Original record requirements: Records should be true and accurate, and should not be tampered with or written in pencil.
Lab report requirements: The report should clearly indicate the criteria, conclusions and test details.
Specimen management: The specimen should be numbered and kept properly, and the number and date of the experiment should be recorded.
Technical team: Technicians with reasonable knowledge structure and physical condition.
Chemical reagent management
Separate storageFlammable, highly toxic, highly corrosive, explosive and strong oxidant reagents should be stored separately, and attention should be paid to storage conditions such as temperature and ventilation.
3. Summary
There are various methods for determining the thickness of galvanized coatings, each with its own unique application scenarios and advantages and disadvantages. Non-destructive methods, such as magnetic, eddy current, X-ray fluorescence, and ultrasonic, are suitable for rapid, on-site testing and can effectively avoid damage to the sample, but their equipment cost and operational complexity vary. Magnetic and eddy current methods are commonly used for thickness measurement on ferrous and non-ferrous substrates, while X-ray fluorescence is suitable for applications where high precision is required, and ultrasonic methods are suitable for measuring thicker coatings. In contrast, destruction methods such as weighing and metallurgical microscopy provide higher measurement accuracy but can damage the sample, making them suitable for laboratory analyses that require high detail in the structure of the coating.
The requirements of the laboratory room emphasize the rigor of environmental control to ensure the accuracy of test results and the normal operation of the equipment. Laboratories need to have a stable temperature and humidity control system to avoid interference from the external environment on the experimental results. The equipment should be placed reasonably to ensure the smooth progress of the experimental process. At the same time, the laboratory should be equipped with necessary safety facilities, such as ventilation systems and fire extinguishers, to ensure the safety of staff. When selecting equipment, consider its compatibility with the laboratory environment to improve productivity and reduce environmental impact.
