High temperature corrosion detection

High temperature corrosion detection is a technology that evaluates the deterioration or damage process of materials caused by chemical or electrochemical reactions with surrounding media in high temperature environments. Its core purpose is to predict material life, optimize material selection, and ensure safe operation of equipment.

High temperature corrosion detection is a technology that evaluates the deterioration or damage process of materials caused by chemical or electrochemical reactions with surrounding media in high temperature environments. Its core purpose is to predict material life, optimize material selection, and ensure safe operation of equipment.

1、 Detection principle

High temperature corrosion is a phenomenon in which materials undergo chemical or electrochemical reactions with elements such as oxygen, sulfur, carbon, and nitrogen in the environment at high temperatures, resulting in material deterioration or damage. Its driving force comes from the Gibbs free energy change in thermodynamics, and the oxidation rate significantly accelerates with increasing temperature. For example, metals react with oxygen at high temperatures to produce oxides, or react with sulfides to produce sulfide corrosion products, which accelerate material loss.

2、 Testing method

There are various methods for high-temperature corrosion detection, covering non-destructive and destructive techniques:

Non destructive testing:

Ultrasonic thickness measurement method: By measuring the propagation time of ultrasonic waves in the material, the remaining wall thickness is calculated to evaluate the degree of corrosion. Suitable for regular inspection of equipment such as pipelines and storage tanks.

Electrochemical corrosion potential method: measures the potential change of materials in corrosive media to determine the corrosion tendency. Commonly used in laboratory simulation environments or on-site rapid screening.

Electrochemical impedance spectroscopy: By analyzing the impedance changes of materials under alternating current, information on corrosion rate and mechanism can be obtained. Suitable for studying the dynamic changes in corrosion processes.

Linear polarization method: Measure the current response of materials at small polarization potentials, calculate the corrosion current density, and evaluate the corrosion rate. Easy to operate, suitable for on-site testing.

Destructive testing:

Sampling analysis method: Samples are taken from equipment for laboratory analysis, such as scanning electron microscopy (SEM) to observe corrosion morphology, energy dispersive spectroscopy (EDS) to analyze corrosion product composition, X-ray diffraction (XRD) to determine phase structure, etc. Suitable for precise assessment of local corrosion conditions.

High temperature corrosion test: Place the sample in a high-temperature corrosive environment (such as high-temperature oxidizing atmosphere, sulfur-containing atmosphere, molten salt environment, etc.), maintain it for a certain period of time, remove it, observe the corrosion morphology on the surface of the sample, measure parameters such as corrosion layer thickness and weight changes, and evaluate the corrosion resistance of the material.

3、 Testing equipment

High temperature corrosion detection requires the use of professional equipment to simulate working conditions:

High temperature and high-pressure reactor: used to simulate high-temperature and high-pressure corrosive environments, evaluate the corrosion resistance of materials in supercritical fluids, high-temperature and high-pressure gases, or liquid media. Equipment is usually equipped with temperature and pressure control systems, as well as mixing systems, to ensure stable experimental conditions.

High temperature static water oxygen environment corrosion tester: designed for high-temperature and high water vapor partial pressure environments such as turbine engines, it simulates the process of water vapor oxidation corrosion and evaluates the thermochemical stability of materials. The equipment can independently adjust steam flow rate, vaporization temperature, and gas preheating and mixing to achieve constant humidity gas generation.

High temperature furnace: used for high-temperature oxidative atmosphere testing, such as placing metal samples in a muffle furnace and placing them at a specific temperature and oxygen concentration for several hours to several hundred hours. By comparing the weight of the samples before and after the test, the corrosion rate can be calculated.

Electrochemical workstation: Testing samples in high temperature environments, analyzing the corrosion mechanism and rate of materials by measuring polarization curves, electrochemical impedance spectra, etc.

4、 High temperature corrosion detection technology is widely used in multiple industrial fields:

Petrochemical industry: Evaluate the corrosion resistance of oil and gas pipelines, storage tanks, reactors and other equipment in high-temperature and high-pressure corrosive media, and prevent corrosion leakage accidents.

Power industry: Detect the corrosion status of components such as boiler pipes and turbine blades in high-temperature steam environments to ensure the safe and stable operation of power generation equipment.

Aerospace: Simulate high-altitude, low-temperature, low-pressure, and corrosive environments, test the corrosion resistance of aerospace materials, optimize material selection and coating design.

Marine engineering: Evaluate the corrosion risks of offshore platforms, subsea pipelines, and other facilities in high-temperature seawater environments, and develop anti-corrosion measures.