Easy to open aluminum can inner coating integrity tester

Electrolyte filling: Inject 1% sodium chloride solution into the easy to open aluminum can to be tested. This step is to simulate an acidic environment, as many beverages are acidic. This simulation can more accurately reflect the actual use of the inner coating film. Sodium chloride solution, as an electrolyte, can form a conductive medium, preparing for subsequent voltage application and current monitoring.

Voltage application: A fixed voltage is applied inside and outside the aluminum can through electrodes, usually at 6.3V. Under normal circumstances, the inner coating acts as an insulating layer, preventing current from passing through.

Current monitoring: If the inner coating is intact, the current value will be extremely low, usually ≤ 30mA. This is because the complete inner coating prevents the passage of current, and only extremely weak currents can pass through. However, once there is damage to the inner coating, such as pinholes, cracks, and other defects, the metal substrate will be exposed, and current will form a path through these defects, resulting in a significant increase in current value, which may reach several hundred milliamps. By monitoring the changes in current values, it is possible to determine whether the inner coating is intact.