Basic definition and principle of XRD

1. X-ray diffraction (XRD) is a technique that uses the diffraction phenomenon generated when X-rays interact with crystalline materials to analyze the crystal structure, composition and physical properties of materials. Its principle is based on the Bragg equation: 2dsinθ=nλ

2. Workflow

1. Sample preparation: Powder samples need to be ground to micrometer level, pressed and placed on the sample table; block samples need to be polished.

2. X-ray irradiation: X-rays are incident on the sample, and the regularly arranged atoms in the crystal cause the X-rays to diffract.

3. Signal acquisition: The detector records the diffraction intensity at different θ angles and generates a diffraction spectrum (2θ is the horizontal axis and the intensity is the vertical axis).

4. Data analysis: Determine the crystal structure parameters by matching the spectrum with a standard database (such as a PDF card).

Measuring oxygen content in X-ray scattering analysis mainly serves three types of needs: accurate material characterization, elimination of test interference, and specific industrial quality control. The specific principles and applications are as follows:

1. As a key analysis object: characterization of material oxidation state ‌Oxide layer thickness and composition analysis Surface oxidation of metal materials (such as alloy wires) will form a nano-scale oxide layer. Through grazing incidence X-ray scattering (such as GIWAXS) or X-ray photoelectron spectroscopy (XPS) combined with ion etching, the thickness of the oxide layer and the chemical state of oxygen elements (such as distinguishing metal oxides from organic oxygen) can be quantitatively determined. ‌Nanomaterial structure analysis ‌ The nanoscale orderliness of oxygen-containing functional materials (such as perovskite films, metal oxide catalysts) directly affects the performance. ‌Small angle X-ray scattering ‌ (SAXS/GIWAXS) analyzes the material crystal quality and assembly structure through the electron density distribution involving oxygen atoms.

2. Eliminate the interference of oxygen on the test: improve quantitative accuracy ‌Light element scattering correction‌ Oxygen (atomic number 8) is a light element with a large X-ray scattering cross section. When it exists in the sample, it will obviously absorb/scatter the incident X-rays, resulting in distortion of the heavy element detection signal. By ‌pre-determining the oxygen content‌, a correction model can be established to optimize the element quantitative results. For example: When analyzing oxide samples by X-ray fluorescence spectroscopy (XRF), an ‌oxygen correction algorithm‌ is required to compensate for its absorption effect on characteristic X-rays1; The presence of oxygen in amorphous materials will change the morphology of the SAXS scattering curve and needs to be used as a variable in structure fitting. ‌Avoid substrate signal interference‌ In thin film material testing, oxygen-containing substrates (such as glass and ceramics) may produce strong scattering backgrounds. Accurate oxygen content data helps to distinguish between sample and substrate signals.

3. Quality control requirements for industrial scenarios ‌Material purity monitoring‌ Trace oxygen in target materials and metal powders will change the sputtering film properties (such as conductivity and adhesion), and the oxygen content needs to be monitored in real time by ‌XRF‌ or ‌oxygen analyzer‌. ‌Process Optimization‌ In high temperature processes such as welding and smelting, oxygen content directly affects product performance (such as weld strength and alloy toughness). Online oxygen monitoring can regulate the atmosphere, inhibit the generation of harmful oxides, and monitor welding shielding gas/molten metal online at the ppm level.

The OXY-GC-168 oxygen analyzer is an oxygen analyzer developed for harsh environment applications. It is a very reliable, compact and economical oxygen analyzer. This analyzer uses a fast-response LT zirconia sensor that can measure oxygen concentrations from 1ppm to 25%. Features such as fast response, high accuracy and no need for regular calibration make this analyzer a low-maintenance analyzer that can provide reliable performance for process control applications.