Handheld XRF (X-ray Fluorescence Spectrometer) uses X-ray excitation characteristic spectroscopy analysis technology to achieve synchronous non-destructive testing of coating thickness and composition. Its core principle and operating process are as follows:
1、 Technical principles
X-ray excitation and fluorescence generation
The instrument emits high-energy X-rays to irradiate the surface of the sample, knocking out electrons in the inner layer of the coating or substrate atoms, forming holes. When the outer electron transitions to fill the hole, it releases characteristic X-ray fluorescence, whose energy corresponds one-to-one with the atomic number of the element (such as nickel, gold and other coating elements have specific energy peaks).
Correlation analysis between thickness and composition
Thickness measurement: The degree of absorption of incident X-rays by the coating is related to its thickness. The thicker the coating, the weaker the fluorescence signal generated by the substrate material (because X-rays are absorbed more by the coating). By measuring the intensity ratio of characteristic fluorescence between the coating and substrate, combined with mathematical models such as standard curve method or theoretical parameter method, the thickness of the coating can be inferred.
Composition analysis: The characteristic X-ray energy released by different elements is different. After the detector captures the spectrum, the element type and relative content are identified through spectral analysis software.
2、 Operation process
Sample preparation
Ensure that the surface to be tested is clean, free of grease or contaminants, and avoid interfering with the test results.
instrument calibration
Perform initial calibration using standard samples (such as coating sheets of known thickness), match the preset curve of the coating substrate combination (such as nickel iron, gold copper), or calculate directly using the FP method (basic parameter method).
Measurement and Data Analysis
Lightly touch the probe onto the surface of the sample, start the measurement program, and the instrument will automatically emit X-rays and collect reflected signals.
The software processes fluorescence spectra and generates thickness values (usually ranging from 0.005-50 μ m, depending on the material) and composition reports within 30 seconds.
Support multi-layer coating analysis (up to 5 layers) to adapt to complex structures.
3、 Technical advantages
Non destructive and fast: No need to damage the sample, single measurement only takes tens of seconds, suitable for real-time quality control on production lines.
High precision: resolution up to 0.005 μ m, dynamic range covering nanometer to micrometer thickness.
Portable and flexible: The handheld design can test large or irregular samples (such as curved surfaces, concave convex surfaces) without the need for cutting and inspection.
Multifunctionality: Synchronize output of thickness and composition data, supporting substrates such as metal, plastic, ceramics, as well as various types of coatings such as gold plating and nickel plating.