The composition of metal is the main factor that determines the performance of materials. Understanding the composition and performance of metal can better apply materials to products. At the same time, by analyzing the composition of metal materials, we can understand the composition of materials and monitor the product quality. In addition, by analyzing the products with problems, we can also understand the causes and eliminate hidden dangers.

Several commonly used metal material detection methods

A. Spectrophotometry

B. Capacity analysis method

C. Spark direct reading spectrometry

D. Atomic absorption spectrometry

E. Inductively coupled plasma spectrometry

F. X-ray fluorescence spectrometry

G. Carbon and sulfur analysis in materials

H. Oxygen and nitrogen analysis method in materials

Spectrophotometry

Spectrophotometry is a method for qualitative and quantitative analysis of a substance by measuring its absorbance at a specific wavelength or within a certain wavelength range. Only one element can be parsed at a time.

Volumetric analysis

Volumetric analysis is to add a reagent solution with known accurate concentration (called standard solution) to the solution of the substance to be measured until the chemical reaction is complete, and then calculate the content of the component to be measured according to the concentration and volume of the reagent solution used. This method is applicable to the test of various substances with a content of more than 1%.

Direct spark reading spectrometry

Spark direct reading spectrometer is a fast quantitative analysis instrument for analyzing the composition of ferrous and non-ferrous metals. It is widely used in metallurgy, machinery and other industrial sectors. Online analysis before smelting furnace and product inspection in central laboratory are one of the effective means to control product quality. This method can be used for multi-element analysis at the same time, but it has requirements on the shape and size of the sample.

Atomic absorption spectrometry

Atomic absorption spectrometry is an instrument analysis method for determining the content of the element in the sample based on the resonance absorption of the ground-state atom of the element in the sample vapor phase to the characteristic narrow-band radiation of the atom emitted by the light source, and its absorbance is proportional to the ground-state atom concentration of the element in the vapor phase within a certain range.

Inductively coupled plasma spectrometry

Inductively coupled plasma emission spectrometry is the most widely used method at present. The principle is that when the sample aerosol enters the plasma flame, most of it immediately decomposes into excited atomic and ionic states. When these excited particles are recovered to a stable ground state, they should emit a certain amount of energy (expressed as a spectrum of a certain wavelength), and measure the specific spectral lines and intensity of each element. Compared with the standard solution, we can know the type and content of the elements contained in the sample. The advantages of this method are wide range of testing, high sensitivity, fast analysis speed and high accuracy. It can be used to test batches of samples under a single line, and to test multiple elements at the same time.

X-ray fluorescence spectrometry

X-ray fluorescence spectrometry is mostly used to determine metal elements, and is also a common method to determine the composition of metal materials. The test principle is that when the X-ray energy of the irradiated atomic nucleus is in the same order of magnitude as the energy of the inner electron of the atomic nucleus, the inner electron of the nuclear resonance absorbs the radiation energy of the ray, and then a hole is left in the inner electron orbit. The outer electron in the high-energy state jumps back to the hole in the low-energy state, and the excess energy is released in the form of X-ray, The X-ray generated is the X-ray fluorescence spectrum line representing the characteristics of each element. Its energy is equal to the energy level difference of the shell electrons in the atom, that is, the atomic specific electron interlayer transition energy. As long as the wavelength of a series of X-ray fluorescence lines is measured, the species of elements can be determined; The content of this element can be determined by measuring the spectral line strength and comparing it with the standard sample.

Carbon and sulfur analysis in materials

In metal materials, especially steel, carbon and sulfur are the main test elements, and the above methods cannot directly quantify carbon and sulfur. Therefore, carbon and sulfur elements need to be tested by carbon and sulfur analyzer. After purification, the carrier gas (oxygen) is introduced into the combustion furnace (resistance furnace or high-frequency furnace). The sample is oxidized by oxygen at high temperature in the combustion furnace, so that the carbon and sulfur in the sample are oxidized to CO2, CO and SO2. The generated oxide is loaded into the sulfur detection tank by oxygen after passing the dust removal and water removal purification device. After that, the mixed gas containing CO2, CO, SO2 and O2 enters into the heated catalyst furnace, where the catalyst furnace undergoes catalytic conversion of CO → CO2, SO2 → SO3. After entering the sulfur removal reagent tube, the mixed gas is introduced into the carbon detection tank to determine carbon.

Analysis of oxygen and nitrogen in materials

The oxygen and nitrogen analyzer decomposes the sample by pulse heating through the oxygen and nitrogen analyzer in an inert atmosphere, and determines the content of oxygen and nitrogen in various steel, non-ferrous metals and new materials by infrared detector and thermal conductivity detector. It has the characteristics of high accuracy and low detection limit. It is applicable to the accurate determination of oxygen and nitrogen content in black, non-ferrous, ceramic, rare earth and magnetic materials in gold, machinery, scientific research, chemical industry, commodity inspection and quality inspection and other industries.