Text/Da Zhuang Laboratory
For the electrochemical study of the corrosion behavior of 9Cr heat-resistant steel with different Si element content in acidic environment, electrochemical workstation or electrochemical test equipment was used to change the electrode potential at a certain rate and record the current response.
In the acidic environment, the polarization curves of samples with different Si element content can be obtained by scanning potential and different scanning rates, and the corrosion behavior of the specimen, such as corrosion rate and corrosion mechanism, can be understood by analyzing the inflection point and polarization resistance of the polarization curve.
AC impedance spectroscopy, in an acidic environment, samples with different Si element content are used as working electrodes, and the reference electrode and counting electrode form an electrochemical cell, under the condition of constant potential, a small amplitude of sinusoidal AC voltage disturbance is applied to record the current response on the working electrode.
By performing the Fourier transform on the current-voltage response, the impedance spectrum in the frequency range is obtained, and the characteristic frequencies in the impedance spectrum, such as charge transfer resistance, electric double-layer capacitance and other parameters, can be analyzed, and the electrochemical behavior and corrosion mechanism of the sample can be studied.
Tafel slope analysis, obtain enough current-potential data points through polarization curve or AC impedance spectrum, plot the relationship between current density and potential according to Tafel equation, can calculate corrosion rate, and compare the differences between samples with different Si element content.
The above method can reveal the electrochemical behavior of 9Cr heat-resistant steel deposition metal lead bismuth with different Si element content in acidic environment, and help to understand its corrosion performance, and attention should be paid to selecting the appropriate acid solution, controlling temperature and pH value, and ensuring the accuracy and stability of experimental equipment during the experiment.
First, the effect of Si content on the corrosion performance of 9Cr heat-resistant steel deposition metal lead bismuth corrosion performance and mechanism analysis
Si content is one of the important factors affecting the corrosion performance of 9Cr heat-resistant steel deposition metal lead bismuth, Si element is generally considered to improve the oxidation, corrosion resistance and wear resistance of the alloy, Si reacts with oxygen and sulfur to form a high melting point silicate, forming a dense silicon oxide (SiO2) protective film, thereby resisting the corrosion of the medium.
Si can also form a solid solution with Fe, improve the mechanical properties of the alloy, Si content has a certain effect on the corrosion performance of lead bismuth in 9Cr heat-resistant steel deposited metal, with the increase of Si content, the corrosion rate of lead bismuth of the deposition metal decreases, and the silicon content in the corrosion products formed will also increase.
Regarding the influence mechanism of Si on the corrosion properties of lead bismuth, Si elements can inhibit the precipitation and growth of calcifications, manganese carbides and other inclusions in the deposition metal, thereby improving the compactness and uniformity of the deposition metal, preventing the medium from invading the interior, and protecting the deposition metal from corrosion.
Si elements react with lead and bismuth in lead bismuth corrosion medium to form composite oxides, and work with other elements (such as Cr, Mo, etc.) to enhance the corrosion resistance of the deposition metal, Si elements by accelerating the formation of stable phase (such as Laves phase), inhibit the formation of disordered crystals, thereby preventing the medium from invading the interior and improving the compactness and corrosion resistance of the deposition metal.
Si content can have an impact on the corrosion performance of lead bismuth in 9Cr heat-resistant steel deposition, the specific mechanism of action may involve many factors, in order to better improve the lead bismuth corrosion performance of deposition metal, it is necessary to comprehensively consider the selection of Si content and other factors such as welding parameters and alloying element composition.
Second, the corrosion behavior of predominated metal lead bismuth in heat-resistant steel with different Si element content of 9Cr in high temperature environment
Si content is one of the important factors affecting the corrosion behavior of 9Cr heat-resistant steel deposition metal lead bismuth in high temperature environment, and some studies have compared the corrosion behavior of 9Cr heat-resistant steel deposition metal lead bismuth in high temperature (500°C and 550°C) lead bismuth liquid environment with different Si element content (usually 0, 0.5, 1 and 2 wt.%).
With the increase of Si content, the corrosion rate of lead bismuth of the deposition metal gradually decreases, and the silicon content in the corrosion product also gradually increases, and the difference in the corrosion behavior of 9Cr heat-resistant steel deposition metal lead bismuth in high temperature environment with different Si element content may involve many factors.
Si element can inhibit the precipitation and growth of inclusions in the deposition metal, thereby improving the compactness and uniformity of the deposition metal, preventing the medium from invading the inside, protecting the deposition metal from being corroded, Si element reacts with lead and bismuth in the lead-bismuth corrosion medium to form composite oxides, and works with other elements (such as Cr, Mo, etc.), thereby enhancing the corrosion resistance of the deposition metal.
Si element accelerates the formation of Laves phase to form a more complete solidification structure, thereby inhibiting the formation of disordered crystals, improving the compactness and corrosion resistance of the deposition metal, in view of the fact that Si element can significantly improve the corrosion resistance of 9Cr heat-resistant steel deposition metal lead bismuth in high temperature environment, its application prospects are very extensive.
When welding 9Cr heat-resistant steel deposited metal lead-bismuth, the content of Si elements should be reasonably controlled according to the actual situation to obtain the best corrosion resistance in a high temperature environment.
Different Si element content has a significant effect on the corrosion resistance of 9Cr heat-resistant steel deposition metal lead bismuth, with the increase of Si element content, the corrosion rate of 9Cr heat-resistant steel deposition metal lead bismuth gradually decreases, higher Si content can form a dense oxide layer, prevent the invasion of corrosion medium, thereby providing better corrosion resistance.
The corrosion products formed during corrosion of 9Cr heat-resistant steel deposition metal lead bismuth with different Si content also differed, and samples with higher Si content contained more silicon compounds in the corrosion products, which may help to further enhance the corrosion resistance of the material.
Effect of different Si content on corrosion resistanceSi element participates in the oxidation reaction, forming a dense silica layer, which blocks the further erosion of the corrosive medium.
Si elements can form composite oxides or silicides with lead bismuth and work with other alloying elements to enhance the corrosion resistance of the material, and Si elements promote the formation of stable phases (such as Laves phase), inhibit the formation of disordered crystals, and improve the compactness and corrosion resistance of the material.
Higher Si element content of 9Cr heat-resistant steel deposition metal lead bismuth performance is better in terms of corrosion resistance, in the specific application, need to comprehensively consider other factors, welding process, material composition, etc., to determine the best Si element content, further improve the corrosion resistance of 9Cr heat-resistant steel deposition metal lead bismuth metal.
Third, the modification effect of Si element addition on the corrosion resistance behavior of lead bismuth in 9Cr heat-resistant steel deposit
The addition of Si element has a modifying effect on the corrosion resistance behavior of 9Cr heat-resistant steel deposition metal lead bismuth, and Si element can react with lead and bismuth in lead bismuth corrosion medium and form composite oxides or silicides, thereby improving the corrosion resistance of the material.
At the same time, Si elements also help to form a dense silicon oxide layer, prevent the invasion of corrosive media, thereby further improving the corrosion resistance of the material, Si elements can promote the formation of stable phase (such as Laves phase), inhibit the formation of disordered crystals, thereby improving the microstructure of the material, improving the compactness and corrosion resistance of the material.
The addition of Si elements can inhibit the precipitation and growth of inclusions in the deposited metal, thereby improving the uniformity and compactness of the material, preventing the erosion of the corrosive medium at the inclusion, thereby improving the corrosion resistance of the material.
The addition of Si element has obvious modification effect on the corrosion resistance behavior of 9Cr heat-resistant steel deposition metal lead bismuth, reasonable control of Si element content can effectively improve the corrosion resistance of the material, and can improve the microstructure and uniformity of the material, improve its overall performance, in practical applications, should reasonably control the Si element content to achieve the best corrosion resistance.
The alloy design based on Si elements can optimize the corrosion performance of 9Cr heat-resistant steel deposition metal lead bismuth, alloying design, by adding appropriate amount of Si elements and other alloying elements, such as Cr, Mo, etc., can form alloyed deposition metal to improve its corrosion resistance.
These alloying elements can react with lead bismuth to form stable oxides or silicides, forming a dense protective layer, hindering the invasion of corrosive media, and increasing the content of Si elements: increasing the content of Si elements can further enhance the corrosion resistance of the material, and higher Si content helps to form more silicon compounds and further improve the corrosion resistance of the material.
Control the content of other alloying elements: In addition to Si elements, it is also important to control the content of other alloying elements, for example, the appropriate amount of Cr and Mo content can improve the corrosion resistance of the alloy, at the same time, it is also necessary to balance the content of various alloying elements to ensure the stability and compactness of the alloy structure to improve the overall corrosion resistance.
Optimization of the deposition process: In practical applications, the appropriate welding process is also very important. Optimizing the deposition process can reduce the formation of defects and inclusions, improve the compactness and uniformity of the deposition layer, and thus improve the corrosion properties of the material.
The alloy design based on Si elements can optimize the corrosion properties of 9Cr heat-resistant steel deposition metal lead-bismuth by reasonably controlling the content of Si elements, other alloying elements and optimizing the deposition process. In practical applications, it is necessary to consider the above factors comprehensively and verify experimentally to obtain the best corrosion resistance.
4. Experimental and simulation study on corrosion behavior of predominated metal lead bismuth in acidic environment of heat-resistant steel with different Si element content of 9Cr
The corrosion behavior of 9Cr heat-resistant steel with different Si content in acidic environment can be studied by combining experiments and simulations. The following are possible experimental and simulation methods:
Experimental method: prepare a deposition metal lead-bismuth sample of 9Cr heat-resistant steel with different Si element content, expose the sample to an acidic environment, such as concentrated nitric acid or sulfuric acid solution, and set different temperature and immersion time conditions.
Regularly take out the sample, observe the corrosion morphology, measure the corrosion rate and other indicators, use electrochemical methods, such as polarization curve, AC impedance, etc., to study the electrochemical behavior and corrosion mechanism of the sample, and compare the corrosion behavior of samples with different Si element content in acidic environment.
Simulation method: Using computer software, such as finite element analysis software, to establish a model of 9Cr heat-resistant steel deposited metal lead-bismuth. Set simulation conditions, including Si content, temperature in acidic environment, solution composition, etc.
Corrosion simulation, calculate the corrosion rate, corrosion morphology and electrochemical behavior of the sample in the acid environment, analyze the simulation results, compare the influence of different Si element content on corrosion behavior, and the method of combining experiments and simulations can verify and supplement each other to help understand the corrosion behavior of 9Cr heat-resistant steel deposition metal lead bismuth with different Si element content in acidic environment.
By synthesizing the results of experiments and simulations, recommendations can be made to optimize the Si content to improve the acid-resistant corrosion performance of the material, please note that when conducting experiments and simulations, it is necessary to follow the relevant safety practice specifications and ensure the accuracy and reliability of the experiments and simulations.