The non-destructive measurement methods of thermal spray coating thickness mainly include the following. Different non-destructive measurement methods are suitable for different types of coating and measurement requirements. When measuring the thickness of thermal spray coating, the appropriate measurement method should be selected according to the specific coating materials and experimental requirements, and the relevant operating procedures and standards should be followed. In addition, when using non-destructive measurement methods, the accuracy of the instrument and the reliability of the measurement results should be ensured, and calibration and verification should be carried out if necessary.

X-ray diffraction (XRD) : The thickness of the coating can be determined by measuring the X-ray diffraction pattern of the thermal spray coating and analyzing the position and intensity of the diffraction peak. This method is suitable for measuring the thickness of metal or ceramic coatings.

Ultrasonic thickness measurement: an ultrasonic detector is used to scan the thermal spray coating, and the thickness of the coating is calculated by measuring the propagation time of the ultrasonic wave and the reflected signal. This method is suitable for measuring the thickness of metal coatings and some ceramic coatings.

Laser scanning measurement: using a laser scanner or laser range finder to scan the coating surface, measure the distance between the laser and the coating, and calculate the thickness of the coating according to the scanning results. This method is suitable for thinner coatings and flat surfaces.

Method for nondestructive measurement of thermal spray coating thickness

Magnetic induction method: The magnetic field intensity or magnetic induction intensity of the coating surface is measured by magnetic induction measuring instrument, and the thickness of the coating is deduced by calibration curve or related algorithm. This method is suitable for measuring the thickness of magnetic coatings.

Infrared thermal imaging: The heat distribution image of the coating surface is recorded by the infrared thermal imager, and the thickness of the coating is inferred from the change of the heat distribution. This method is suitable for coatings with thermal barrier effects, such as thermal barrier coatings.

Magnetic induction method is a common non-destructive measurement method used to measure the thickness of magnetic coating. The following are the general test steps and precautions of magnetic induction method:

Test procedure:

Prepare test instruments: magnetic induction measuring instrument, calibration sample, magnetic coating sample.

Calibration of the magnetic induction meter: calibration is performed using a calibration sample to determine the sensitivity and zero point of the instrument.

Prepare the magnetic coating sample: Make sure the coating surface is flat and clean, and ensure that the magnetic properties of the coating are good.

Place the magnetic induction meter close to the coating surface and maintain a suitable distance.

Start the magnetic induction measuring instrument and make the measurement and record the measurement results.

According to the calibration curve of the instrument or the related algorithm, the thickness of the magnetic coating is deduced.

Method for nondestructive measurement of thermal spray coating thickness

Notes:

Preparation of the sample surface: The coated surface should be smooth and clean without obvious bumps or contamination to ensure the accuracy of the measurement results.

Calibration of the instrument: Before making the measurement, make sure that the magnetic induction measuring instrument has been correctly calibrated to ensure the accuracy of the measurement results.

Selection of measurement position: Select the appropriate measurement position, and usually choose to take multiple measurements in different areas of the coating to obtain a more accurate average value.

Control of measuring distance: ensure that the distance between the magnetic induction measuring instrument and the coating surface is constant, avoid too close or too far, to ensure the stability of the measurement results.

Method for nondestructive measurement of thermal spray coating thickness

Repeatability and accuracy: Take multiple measurements and calculate the average to improve the repeatability and accuracy of the measurement results.

Calibration curve and algorithm: according to the specific type of magnetic induction measuring instrument and coating material, select the appropriate calibration curve or algorithm to calculate the measurement results.

Use of calibration samples: Check and replace calibration samples regularly to ensure the accuracy of the measuring instrument.

Safety precautions: In the operation process, pay attention to the safe use of the instrument and personal safety protection.

Specific test procedures and precautions may vary depending on the magnetic induction meter and coating material. Before conducting the test, it is recommended to refer to the operation manual of the magnetic induction meter and the relevant standards and procedures to ensure correct operation and accurate measurement.