Penetration flaw detection agent for stable development in high-temperature environment and preparation method of penetrant flaw detection agent

Abstract

The invention relates to the field of nondestructive testing, and discloses a penetrant flaw detection agent for stable development in a high-temperature environment and a preparation method of the penetrant flaw detection agent. A cosolvent; a nano titanium dioxide imaging agent; a fluorinated surfactant; high temperature resistant polyamide; the aromatic ether solvent is diphenyl ether or diphenyl ether, and the boiling point range of the aromatic ether solvent is 250-270 DEG C; the cosolvent is triethylene glycol monoether, and the boiling point range of the cosolvent is 250-280 DEG C. A high-temperature stable liquid matrix mainly comprising an aromatic ether solvent is adopted, through the synergistic effect of a combined cosolvent, it is ensured that the penetrant flaw detection agent still has low volatility and high chemical stability in a high-temperature environment, and compared with a low-boiling-point solvent scheme generally adopted in the prior art, the penetrant flaw detection agent has the advantages of low volatility and high chemical stability. According to the invention, the problem of work failure of the penetrant flaw detection agent caused by solvent volatilization is avoided, and the applicability and reliability in high-temperature crack detection are improved.

Description

Technical Field

[0001] The invention relates to the technical field of nondestructive testing, in particular to a penetrant flaw detection agent for stable imaging in a high temperature environment and a preparation method thereof. Background Art

[0002] As a non-destructive testing method, penetrant testing technology has been widely used in the detection of surface cracks and defects in industrial equipment, especially in the fields of aerospace, nuclear industry and metallurgy. Existing penetrant testing agents are usually composed of low-boiling point or medium-boiling point solvents, developer particles and surfactants. With their simple and efficient operation process, they have become an important tool for detecting microcracks. Especially under normal temperature conditions, these flaw detection agents can play a good imaging effect. However, when the application environment gradually changes to high temperature conditions, the performance of the flaw detection agent is often difficult to maintain consistency. Although some technologies have improved the scope of application of flaw detection agents by using modified developers or improving solvent performance, the stability of the overall performance still needs to be further optimized.

[0003] Under high temperature environment, the flaw detection agents of the prior art expose some limitations. First, since the solvent matrix mostly adopts medium and low boiling point solvents, which evaporate quickly and have poor chemical stability, it is difficult for the flaw detection agent to maintain sufficient penetration time under high temperature conditions, thus affecting the imaging integrity of the cracks. Secondly, the dispersibility and stability of the developer particles in the solvent matrix are poor, and it is easy to cause uneven imaging effects due to agglomeration or sedimentation, especially in the deep crack imaging. There are significant deficiencies. In addition, the fixation design of the developer in the crack is relatively weak, and the developer is prone to detachment under high temperature environment, resulting in poor durability of the imaging effect. At the same time, the use of non-fluorinated surfactants in existing flaw detection agents is difficult to provide sufficient capillary penetration capacity under high temperature conditions, and the permeability and imaging effects in the crack depth direction are often unsatisfactory. Therefore, how to further optimize the high temperature stability and imaging performance of the flaw detection agent on the basis of maintaining the advantages of the prior art is still an important technical problem facing the field of penetrant flaw detection. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a penetrant flaw detection agent for stable development in a high temperature environment and a preparation method thereof, which solves the problem that the existing penetrant flaw detection agents have unstable development effects due to solvent volatilization, uneven dispersion of the developer, insufficient penetration into the cracks and poor fixation of the imaging particles in a high temperature environment.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A penetrant flaw detection agent for stable imaging in a high temperature environment, comprising the following component materials: Aromatic ether solvent: 65 to 80 parts; Cosolvent: 8 to 12 parts; Nano titanium dioxide developer: 4 to 8 parts; Fluorinated surfactant: 2 to 5 parts; High temperature resistant polyamide: 3 to 6 parts.

[0006] Furthermore, the aromatic ether solvent provides a high temperature stable liquid matrix, and its high boiling point characteristic (250-270°C) reduces the volatility of the flaw detection agent and enhances the fluidity of the penetrant in high temperature cracks.

[0007] Cosolvents such as triethylene glycol monoether can enhance the solubility of the developer, improve the dispersibility, and increase the uniformity of the solvent system.

[0008] Nano-titanium dioxide developer achieves high-contrast crack imaging through its excellent light scattering ability, and its nano-scale particle size (30-50nm) ensures that it can enter micron-sized cracks.

[0009] Fluorinated surfactants reduce the surface tension of the flaw detector, allowing the flaw detector to penetrate deeper into the crack and form an adsorption layer on the crack surface, thereby improving the crack imaging effect.

[0010] The high temperature resistant polyamide is used to fix the distribution of the imaging particles in the high temperature cracks to prevent the diffusion and failure of the imaging particles in the high temperature environment.

[0011] Preferably, the aromatic ether solvent is biphenyl ether or diphenyl ether, and its boiling point ranges from 250°C to 270°C.

[0012] Furthermore, biphenyl ether and diphenyl ether have a higher boiling point (250℃~270℃) and lower volatility, which ensures that the solvent is not easy to volatilize and decompose in a high temperature environment, maintaining the working stability of the flaw detection agent. At the same time, the rigid structure of aromatic ether molecules can reduce the thermal vibration of the molecular chain under high temperature conditions, further enhancing its chemical stability, so that the flaw detection agent can maintain its liquid properties for a long time in a high temperature environment, facilitating the filling and penetration of cracks.

[0013] Preferably, the co-solvent is triethylene glycol monoether, and its boiling point ranges from 250°C to 280°C.

[0014] Furthermore, triethylene glycol monoether is used as a cosolvent, and its polarity helps dissolve the nanoparticles in the developer, reduces their tendency to agglomerate, and ensures the uniform dispersion of the developer particles in the solvent matrix. In addition, the high boiling point of triethylene glycol monoether (250°C to 280°C) enables it to maintain a liquid state in a high temperature environment, further enhancing the overall thermal stability of the flaw detection agent.

[0015] Preferably, the particle size of the nano titanium dioxide developer is 30 nm to 50 nm, and is modified by a silane coupling agent.

[0016] Furthermore, nano-titanium dioxide particles have good light scattering properties, which can enhance the contrast of crack imaging. Nanoparticles with a particle size of 30nm to 50nm have appropriate Brownian motion ability, which can maintain uniform dispersion in the solvent while adapting to the micron scale of the crack. In addition, after the titanium dioxide developer is modified by a silane coupling agent, its surface lipophilicity is enhanced, and its compatibility with aromatic ether solvents is improved, avoiding particle agglomeration, thereby ensuring the dispersibility and stability of the flaw detector developer.

[0017] Preferably, the fluorinated surfactant is a potassium hexafluorophosphate derivative, and its molecular structure comprises a hydrophilic group and a fluorinated segment.

[0018] Furthermore, the fluorinated segments in the fluorinated surfactants have lower surface energy, which can effectively reduce the surface tension of the penetrant flaw detector, thereby improving its capillary penetration ability and ensuring that the flaw detector fully penetrates the crack. The introduction of hydrophilic groups enhances the ability of molecules to adsorb on the crack surface, allowing the flaw detector to better fill the crack and maintain its position, further improving the crack imaging effect.

[0019] Preferably, the molecular weight of the high temperature resistant polyamide is 10,000 g / mol to 20,000 g / mol, and the glass transition temperature is 260° C. to 280° C.

[0020] Furthermore, the high molecular weight (10,000 g / mol to 20,000 g / mol) of high temperature resistant polyamide gives it good mechanical properties and thermal stability, and its glass transition temperature (260°C to 280°C) ensures that it will not soften or deform in high temperature environments. In the flaw detector, polyamide mainly fixes the developer particles in the cracks by physical adsorption or chemical bonding to avoid high temperature diffusion or detachment, thereby ensuring the long-term stability of the flaw detector.

[0021] A method for preparing a penetrant flaw detection agent for stable imaging in a high temperature environment comprises the following steps: S1. Add an aromatic ether solvent into a stirring kettle at a temperature of 100°C to 130°C, and control the stirring speed to 400rpm to 600rpm; S2, adding a co-solvent to the aromatic ether solvent, stirring for 20 min to 40 min to form a uniform solvent matrix; S3, adding a portion of nano titanium dioxide developer to the solvent matrix, using an ultrasonic disperser with a frequency of 35kHz to 45kHz and a power of 400W to 600W to disperse for 40min to 60min to obtain a mixture A; S4. Add a fluorinated surfactant to mixture A at 50°C to 70°C and stir for 20min to 30min to obtain mixture B; S5. Add part of the high temperature resistant polyamide to the mixture B at 60°C to 80°C, and stir for 30min to 50min using a high-speed stirrer at a speed of 5000rpm to 7000rpm to obtain a final mixture; S6. The final mixture is homogenized by a high shear mixer with a rotation speed of 6000 rpm to 8000 rpm for 40 min to 60 min, and the penetrant flaw detection agent is obtained after cooling to room temperature.

[0022] Furthermore, in steps S1 to S2, a liquid matrix with high temperature stability is constructed by mixing the solvent and the co-solvent, which provides a uniform dispersion environment for the subsequent addition of components.

[0023] The S3 step adopts an ultrasonic dispersion process, using the cavitation effect of sound waves in liquid to evenly disperse the nano-titanium dioxide particles into the solvent matrix to ensure that the developer particles do not agglomerate.

[0024] The addition of the fluorinated surfactant in step S4 reduces the surface tension of the liquid matrix and forms an adsorption layer on the crack surface.

[0025] In step S5, the high temperature resistant polyamide is uniformly mixed by high speed stirring, so that the position of the developer particles is fixed to prevent diffusion.

[0026] The high shear homogenization treatment in step S6 further improves the distribution uniformity of the flaw detection agent components, making its performance more stable.

[0027] Preferably, in step S3, the particle size of the nano-titanium dioxide developer is controlled within the range of 30 nm to 50 nm by dynamic light scattering detection, and the coefficient of variation of the particle size distribution is less than 5%.

[0028] Preferably, in step S4, the concentration of the fluorinated surfactant added is controlled to be 0.008 mol / L to 0.015 mol / L.

[0029] Preferably, in the step S6, after high shear homogenization treatment, the component distribution error of the penetrant flaw detection agent is less than 3%.

[0030] The present invention provides a penetrant flaw detection agent for stable imaging in a high temperature environment and a preparation method thereof. Beneficial effects: 1. The present invention adopts a high-temperature stable liquid matrix mainly composed of aromatic ether solvents, and through the synergistic effect of the combined co-solvent, ensures that the penetrant flaw detector still has low volatility and high chemical stability in a high-temperature environment. Compared with the low-boiling point solvent solution commonly used in the prior art, the present invention avoids the problem of penetrant flaw detector failure caused by solvent volatilization, and improves the applicability and reliability in high-temperature crack detection.

[0031] 2. The present invention effectively solves the problem of easy agglomeration of developer particles in a liquid matrix by modifying the surface of the nano-titanium dioxide developer with a silane coupling agent and combining it with ultrasonic dispersion technology. Compared with the technical solution in the prior art that directly uses nano-particle developers, resulting in uneven dispersion and unstable imaging effects, the present invention optimizes the dispersion performance of the developer and ensures that the clarity and contrast of crack imaging are greatly improved.

[0032] 3. The present invention utilizes fluorinated surfactants to significantly reduce the surface tension of the flaw detection agent and enhance the adsorption performance of the crack surface. Compared with the flaw detection agent scheme in the prior art that does not fully consider capillary penetration and surface adsorption behavior, the present invention enables the flaw detection agent to penetrate deeper into micron-sized cracks, significantly improving the penetration and coverage ability of the flaw detection agent in complex crack defects.

[0033] 4. The present invention achieves effective fixation of developer particles in high-temperature crack detection scenarios by introducing high-temperature resistant polyamide. Compared with the shortcomings of the prior art that developer particles are easily diffused or detached in high-temperature environments, the present invention maintains the stability of the developer in the cracks, ensures that the developing effect is not affected by high-temperature conditions, and broadens the application field of flaw detection agents in high-temperature complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a flow chart of the preparation method steps. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Please see attached Figure 1 , Example 1: Preparation process: Take 70 parts of diphenyl ether and add it into a stirring kettle, keep the temperature at 110°C, and set the stirring speed to 500 rpm. Then add 10 parts of triethylene glycol monoether and continue stirring for 30 minutes. Stop stirring after observing that the mixed solution is uniform and transparent to obtain a solvent matrix.

[0037] 6 parts of nano titanium dioxide were added to the solvent matrix and dispersed using an ultrasonic disperser (frequency 40 kHz, power 500 W). The dispersion time was set to 50 min and the liquid temperature was maintained at 80° C. After the dispersion was completed, the particle size was detected to be 30 nm to 50 nm, and the coefficient of variation was less than 5%, thereby obtaining a mixture A.

[0038] Transfer mixture A to a new stirring kettle, heat to 60°C, slowly add 3 parts of fluorinated surfactant at 400 rpm, and stir for 25 minutes to obtain mixture B. Then add 4 parts of high-temperature resistant polyamide at 70°C, control the speed at 6000 rpm, continue stirring for 40 minutes, and stop after observing that the mixed solution is uniform and stable.

[0039] Finally, the mixture was processed by a high shear homogenizer with a rotation speed set to 7000 rpm and a homogenization time of 50 min. After cooling to room temperature, the target flaw detection agent was obtained.

[0040] Embodiment 2: Preparation process: 65 parts of diphenyl ether were added into the reaction kettle, the temperature was controlled at 120°C, and the stirring speed was 450 rpm. Then 9 parts of triethylene glycol monoether were added, and stirring was continued for 35 minutes until the solution was mixed evenly and transparent, forming a high-temperature solvent matrix.

[0041] 5 parts of nano titanium dioxide developer were gradually added to the solvent matrix. The frequency of the ultrasonic disperser was adjusted to 35 kHz, the power was adjusted to 450 W, the dispersion time was set to 45 min, the temperature was maintained at 85° C. The particle size of the developer was detected to be between 30 nm and 45 nm, and the mixture A was obtained after ensuring uniform dispersion.

[0042] The mixture A was slowly cooled to 50°C, and 2.5 parts of fluorinated surfactant were gradually added. The stirring speed was set to 500 rpm, and the stirring time was 30 minutes to obtain a mixture B. At 60°C, 3.5 parts of high temperature resistant polyamide were added to the mixture B, and stirred for 50 minutes using a high-speed stirrer with a rotation speed of 5500 rpm to form a final mixture.

[0043] Finally, the mixture was homogenized by a high shear mixer (rotation speed 6500 rpm) for 40 min and cooled to room temperature to obtain a finished penetrant flaw detection agent.

[0044] Embodiment 3: Preparation process: 75 parts of diphenyl ether were added into a 500 L large stirred tank, the temperature was controlled at 130°C, and the stirring speed was 400 rpm. Then 8.5 parts of triethylene glycol monoether were added, and stirred for 25 minutes until the mixture was uniformly mixed to form a solvent matrix.

[0045] 6.5 parts of nano titanium dioxide developer were gradually added to the solvent matrix, and dispersed for 60 minutes using an ultrasonic disperser with a frequency of 45 kHz and a power of 600 W. The temperature was maintained at 80° C. After the dispersion was completed, the particle size was detected to be 40 nm, and the coefficient of variation of the particle size distribution was 3%.

[0046] The dispersed mixture A was transferred to a new stirring container and the temperature was maintained at 70°C. 4.5 parts of fluorinated surfactant were slowly added dropwise at a speed of 500 rpm and stirred for 30 minutes until the solution was uniform to obtain a mixture B. The mixture B was heated to 80°C, 6 parts of high temperature resistant polyamide were added, and stirred for 40 minutes using a high-speed stirrer at a speed of 7000 rpm to form a final mixture.

[0047] Finally, the mixture was homogenized for 45 min using a high shear mixer (rotation speed 8000 rpm), and cooled to room temperature to obtain a finished penetrant flaw detection agent.

[0048] Comparative Example 1: (for Example 1) Note on the difference: In Comparative Example 1, the aromatic ether solvent in Example 1 is replaced with a low boiling point solvent (such as toluene). The remaining materials and process flow remain the same as in Example 1.

[0049] Preparation process: 70 parts of toluene were added into a stirring kettle, the temperature was controlled at 40°C, and the stirring speed was 500 rpm.

[0050] 10 parts of triethylene glycol monoether were added and stirred for 30 minutes to obtain a solvent matrix.

[0051] 6 parts of nano titanium dioxide were added and dispersed using an ultrasonic disperser (frequency 40 kHz, power 500 W). The dispersion time was set to 50 min and the temperature was maintained at 40° C. After the dispersion was completed, a mixture A was obtained.

[0052] At room temperature, 3 parts of fluorinated surfactant were added and stirred for 25 minutes to prepare a mixture B.

[0053] 4 parts of high temperature resistant polyamide were added, the rotation speed was set to 6000 rpm, and high-speed stirring was performed for 40 minutes to obtain a final mixture.

[0054] The product is directly cooled to room temperature without homogenization to obtain a penetrant flaw detection agent.

[0055] Comparative Example 2: (for Example 1) Note on the difference: In Comparative Example 2, the developer is changed to nano titanium dioxide particles without surface modification. The remaining materials, solvents and preparation steps are the same as those in Example 1.

[0056] Preparation process: Take 70 parts of diphenyl ether and add it into a stirring kettle. Keep the temperature at 110°C and set the stirring speed to 500 rpm.

[0057] 10 parts of triethylene glycol monoether were added and stirred for 30 minutes to obtain a solvent matrix.

[0058] 6 parts of nano titanium dioxide particles without surface modification were added, and dispersed for 50 minutes using an ultrasonic disperser (frequency 40 kHz, power 500 W) at a dispersion temperature of 80° C. to form a mixture A.

[0059] At 60°C, 3 parts of fluorinated surfactant were added and stirred for 25 minutes to prepare mixture B.

[0060] 4 parts of high temperature resistant polyamide were added, the rotation speed was controlled at 6000 rpm, and high-speed stirring was performed for 40 minutes to obtain a final mixture.

[0061] After being treated with a high shear homogenizer (rotation speed 7000 rpm) for 50 min and cooled to room temperature, a penetrant flaw detection agent was obtained.

[0062] Comparative Example 3: (for Example 2) Note on the difference: In Comparative Example 3, the fluorinated surfactant is replaced by a non-fluorinated surfactant (such as a polyethylene glycol-based surfactant). The remaining process steps are consistent with Example 2.

[0063] Preparation process: 65 parts of diphenyl ether were added into the reaction kettle, the temperature was controlled at 120°C, and the stirring speed was 450 rpm.

[0064] 9 parts of triethylene glycol monoether were added and stirred for 35 minutes to form a high temperature solvent matrix.

[0065] 5 parts of nano titanium dioxide developer were added, and dispersed for 45 minutes using an ultrasonic disperser (frequency 35 kHz, power 450 W) at a dispersion temperature of 85° C. to obtain a mixture A.

[0066] At 50° C., 3 parts of a polyethylene glycol-based surfactant were added and stirred for 30 minutes to form a mixture B.

[0067] 3.5 parts of high temperature resistant polyamide were added, the rotation speed was controlled at 5500 rpm, and high-speed stirring was performed for 50 minutes to obtain a final mixture.

[0068] The product was homogenized by a high shear mixer (rotation speed 6500 rpm) for 40 min and cooled to room temperature to obtain a flaw detection agent.

[0069] Comparative Example 4: (for Example 2) Note on the difference: In Comparative Example 4, high temperature resistant polyamide was not added. The remaining solvent ratio, developer dispersion process, and surfactant selection were the same as those in Example 2.

[0070] Preparation process: 65 parts of diphenyl ether were added into the reaction kettle, the temperature was controlled at 120°C, and the stirring speed was 450 rpm.

[0071] 9 parts of triethylene glycol monoether were added and stirred for 35 minutes to form a uniform solvent matrix.

[0072] 5 parts of nano titanium dioxide developer were added, and dispersed for 45 minutes using an ultrasonic disperser (frequency 35 kHz, power 450 W) at a dispersion temperature of 85° C. to obtain a mixture A.

[0073] At 50° C., 3 parts of fluorinated surfactant were added and stirred for 30 minutes to obtain a mixture B.

[0074] Without adding high temperature resistant polyamide, the mixture was directly stirred by a high-speed stirrer (rotation speed 5500 rpm) for 40 min to obtain a final mixture.

[0075] The mixture was homogenized by a high shear mixer (rotation speed 6500 rpm) for 40 min and cooled to room temperature to obtain a flaw detection agent.

[0076] Comparative Example 5: (for Example 3) Note on the difference: In Comparative Example 5, the ratio of diphenyl ether to triethylene glycol monoether was adjusted, with diphenyl ether reduced to 60 parts and triethylene glycol monoether increased to 15 parts. The remaining process steps were the same as those in Example 3.

[0077] Preparation process: 60 parts of diphenyl ether were added to a 500 L stirring kettle, the temperature was set to 130° C., and the stirring speed was 400 rpm.

[0078] 15 parts of triethylene glycol monoether were added and stirred for 25 minutes to form a solvent matrix.

[0079] 6.5 parts of nano titanium dioxide developer were added, and an ultrasonic disperser with a frequency of 45 kHz and a power of 600 W was used to disperse the mixture for 60 minutes at a dispersion temperature of 80° C. to form a mixture A.

[0080] The mixture A was transferred to a new stirring container and the temperature was maintained at 70° C. 4.5 parts of a fluorinated surfactant was added and stirred for 30 minutes to obtain a mixture B.

[0081] 6 parts of high temperature resistant polyamide were added, the rotation speed was controlled at 7000 rpm, and high-speed stirring was performed for 40 minutes to form a final mixture.

[0082] The mixture was homogenized by a high shear mixer (rotation speed 8000 rpm) for 45 min and cooled to room temperature to obtain a flaw detection agent.

[0083] Comparative Example 6: (for Example 3) Note on the difference: In Comparative Example 6, the frequency and power parameters of the ultrasonic dispersion process were not set in the ranges of Example 3, but were changed to 30 kHz and 350 W. The remaining materials and process flow were the same as those in Example 3.

[0084] Preparation process: 75 parts of diphenyl ether were added into a 500 L stirring kettle, and the temperature was controlled at 130° C. and the stirring speed was 400 rpm.

[0085] 8.5 parts of triethylene glycol monoether were added and stirred for 25 minutes to form a solvent matrix.

[0086] 6.5 parts of nano titanium dioxide were added, and an ultrasonic disperser (frequency 30 kHz, power 350 W) was used to disperse the mixture for 60 min at a dispersion temperature of 80° C. to obtain a mixture A.

[0087] Mixture A was transferred to a new stirring container and the temperature was maintained at 70° C. 4.5 parts of a fluorinated surfactant was added and stirred for 30 minutes to obtain mixture B.

[0088] 6 parts of high temperature resistant polyamide were added, the rotation speed was controlled at 7000 rpm, and high-speed stirring was performed for 40 minutes to form a final mixture.

[0089] The mixture was homogenized by a high shear mixer (rotation speed 8000 rpm) for 45 min and cooled to room temperature to obtain a flaw detection agent.

[0090] Test experiment: Experiment 1: Volatility test under high temperature conditions Experimental description: Purpose: Evaluate the volatility of penetrant flaw detection agents in high temperature environments (400°C), verify the thermal stability of the solvent matrix, and examine the effects of different solvent systems on the volatility characteristics of the flaw detection agent.

[0091] Experimental steps: Sample preparation: Weigh 5 g of each of the flaw detection agent samples in Example 1, Comparative Example 1 and Comparative Example 5, put them into a high-temperature crucible that was cleaned and dried in advance, and mark them as A1 (Example 1), B1 (Comparative Example 1), and C1 (Comparative Example 5).

[0092] High temperature treatment: Place the crucibles in a high-temperature furnace one by one, set the temperature to 400°C, and keep the temperature constant. Start timing after the high-temperature furnace is preheated to the target temperature.

[0093] Quality Measurement: Every 30 minutes, the mass of the sample was recorded with an electronic balance, with the data accurate to 0.01 g. Before each measurement, the crucible was taken out of the furnace and quickly cooled to room temperature to avoid errors.

[0094] The recording was continued for 2 h until the experiment was completed, and the residual mass of the samples during the process was recorded.

[0095] Results summary: Calculate the mass residual rate of the sample every 30 minutes using the formula: Experimental data: Experimental summary: The flaw detection agent in Example 1 exhibits significant high-temperature stability, with a mass residual rate of 94% within 2 hours, and has superior volatility performance compared to Comparative Examples 1 and 5. Mechanism analysis shows that this difference mainly comes from the high boiling point characteristics of diphenyl ether as a solvent matrix. The boiling point of diphenyl ether is between 250°C and 270°C, and the rigid structure within the molecule can effectively resist volatilization under high temperature conditions. The toluene used in Comparative Example 1 has a lower boiling point (110°C) and evaporates rapidly under high temperature conditions, resulting in a significant decrease in the mass residual rate. Although diphenyl ether is used in Comparative Example 5, the increase in the proportion of co-solvent reduces the thermal stability of the overall system.

[0096] The intermolecular forces of different solvents directly affect the evaporation rate of the flaw detection agent. In Example 1, diphenyl ether and triethylene glycol monoether work synergistically to form a liquid matrix with lower volatility. This synergy comes from the formation of intermolecular hydrogen bonds and polarity matching. In contrast, due to the lack of such intermolecular forces, the thermal vibration of the solvent molecules in Comparative Example 1 is enhanced, and it is easy to escape to the gas phase, resulting in increased volatility. Similarly, the co-solvent content in Comparative Example 5 is too high, which destroys the rigid network of diphenyl ether and weakens the intermolecular forces.

[0097] At the same time, the experimental data show that in high-temperature crack detection, the choice of solvent matrix has a key influence on the actual performance of the flaw detection agent. Example 1 controls the volatility at the lowest level through a stable solvent network. The excessively fast volatilization of the toluene-based comparative example 1 may shorten the penetration time of the flaw detection agent in the crack and cause incomplete imaging. Although the volatilization rate in comparative example 5 is slightly better than that in comparative example 1, the overall stability of the system is reduced, and long-term use may cause the problem of separation of the flaw detection agent components. This difference reflects the innovation of the present invention in the design of the solvent matrix, and also clarifies its practical application advantages.

[0098] Experiment 2: Developer Dispersion Test Experimental description: Purpose: The dispersion uniformity and particle size distribution of the developer in the penetrant flaw detection agent were tested, and the influence of the surface modification of the developer was investigated.

[0099] Experimental materials and equipment: Samples: Example 1, Comparative Example 2.

[0100] Dynamic light scattering (DLS), particle size measurement range: 10nm~1000nm, detection accuracy ±1nm.

[0101] 10mL glass sample bottle, ultrasonic cleaning machine (to remove residue).

[0102] Data analysis software: particle size distribution and coefficient of variation calculation tool.

[0103] Experimental steps: Sample preparation: Take 10 mL of the flaw detection agent samples of Example 1 and Comparative Example 2 respectively, put them into clean glass sample bottles, and shake them thoroughly to mix them so that the samples are evenly distributed.

[0104] Particle size measurement: The particle size was detected using a dynamic light scattering instrument. The temperature was set at 25°C. The light scattering intensity of the sample was tested. The measurement was repeated three times, and the particle size distribution data was recorded each time.

[0105] The average particle size and particle size distribution range of the nano-imaging agent in the sample were analyzed, and the coefficient of variation of the particle size (CV%=standard deviation / average particle size×100%) was calculated.

[0106] Results recorded: The ratio of the number of developer particles within the particle size distribution range of Example 1 and Comparative Example 2 (the ratio of particles within the range of 30-50 nm) and the uniformity of the particle size distribution are compared.

[0107] Experimental data: Experimental summary: The dispersibility of the developer showed significant differences in the two samples. The particle size distribution of Example 1 was more concentrated, with a lower coefficient of variation, and the proportion of particles in the range of 30nm to 50nm was significantly higher than that of Comparative Example 2. This shows that the developer modified with a silane coupling agent is more uniformly dispersed in the solvent matrix, and the agglomeration between particles is effectively suppressed. However, in the unmodified developer in Comparative Example 2, particles are prone to agglomeration, resulting in a shift in the particle size distribution to a larger range and a significant decrease in uniformity. This difference comes from the change in the surface energy of the developer after modification with the coupling agent, and the dispersion of the developer in the solvent is enhanced.

[0108] The dynamic light scattering data further revealed the importance of controlling the particle size of the developer within the range of 30nm to 50nm. In Example 1, more than 92% of the developer particles were distributed within this range, and were able to enter tiny cracks during the flaw detection process, giving full play to the imaging effect. However, the dispersion effect in Comparative Example 2 was poor, the proportion of large-size particles increased, and it was difficult to enter the cracks, limiting the imaging performance. This phenomenon is closely related to the synergistic relationship between the ultrasonic dispersion efficiency. The introduction of the coupling agent optimizes the efficiency of the acoustic cavitation effect, and effectively weakens the interaction force on the particle surface.

[0109] The dispersion problem of the unmodified developer also brings other potential effects, such as the fluctuation of the viscosity of the liquid matrix. This volatility was not eliminated in Comparative Example 2, resulting in poor dispersion stability of the flaw detection agent. However, the developer treated by modification in Example 1 improves the intermolecular force, greatly improves the dispersion uniformity, and ensures the distribution consistency of the developer and the stability of performance in long-term use. These results clearly reflect the key role of the surface modification of the developer in the technical solution of the present invention.

[0110] Experiment 3: Capillary penetration test Experimental description: Purpose: The capillary penetration performance of penetrant inspection agents in micron-sized cracks was evaluated, and the effect of surfactant types on penetration depth was investigated.

[0111] Experimental materials and equipment: Standard crack test panel (10μm width, 1mm depth).

[0112] Samples: Example 2, Comparative Example 3.

[0113] Optical microscope (100× magnification).

[0114] 10mL volumetric flask, temperature control equipment (room temperature maintained at 25°C).

[0115] Experimental steps: Crack test panel preparation: Cracks were made on the metal test panels using standard crack processing equipment, with a crack width of 10 μm and a depth of 1 mm, and the test panels were cleaned to ensure that there was no oil contamination.

[0116] Sample processing: Take 10 mL of the flaw detection agent samples of Example 2 and Comparative Example 3 respectively, shake them evenly at room temperature, and place the samples in a constant temperature environment (25° C.) for later use.

[0117] Experimental operation: Immerse the test plate vertically into the flaw detection agent sample, the crack area is completely immersed, and the immersion depth is 10mm.

[0118] The soaking time is set to 30 minutes, and the mixture is kept still during this period to ensure that the capillary penetration effect is fully exerted.

[0119] After immersion, take out the test panel and let it dry naturally in the air for 10 minutes.

[0120] Data collection: Use an optical microscope to observe the crack imaging, measure the penetration depth of the flaw detector in the crack, and record the penetration length.

[0121] The crack penetration depth was measured 5 times for each sample and the average value was taken.

[0122] Experimental data: Experimental summary: The capillary penetration depth in the crack directly demonstrates the significant difference in the performance of the two flaw detection agents. The flaw detection agent in Example 2 has a higher penetration depth, with an average value of 0.86 mm, while the comparative example 3 is only 0.63 mm. The key to this performance difference lies in the choice of surfactant. In Example 2, a fluorinated surfactant is used, which can significantly reduce the surface tension of the flaw detection agent and improve its capillary penetration ability in the crack. In contrast, the non-fluorinated surfactant in comparative example 3 failed to significantly reduce the surface tension, and the penetration effect was significantly limited. This phenomenon shows that the molecular structure of the surfactant plays a decisive role in the performance of the flaw detection agent.

[0123] The low surface energy characteristics of the fluorinated surfactant enable the flaw detector to form a better wetting effect on the crack interface. Combined with the microstructure of the crack wall, the flaw detector can form a stronger capillary rise force in the crack, thereby enhancing the penetration effect. However, the polarity of the polyethylene glycol-based surfactant in Comparative Example 3 is not suitable for such interfacial wetting, the capillary effect is weakened, and the penetration depth is therefore limited. Through microscopic observation, it can be clearly seen that the flaw detector of Example 2 can penetrate deep into the bottom of the crack, while the flaw detector of Comparative Example 3 mostly stays in the crack entrance area.

[0124] In addition, the adsorption properties of the surfactant also affect the penetration depth. The fluorinated surfactant forms a more stable adsorption layer on the crack wall, which helps the molecules of the flaw detector to move further into the crack. In Comparative Example 3, due to the poor stability of the adsorption layer, the movement path of the penetrant molecules in the crack is shorter, and deep imaging cannot be achieved. The experimental results clearly reflect the core role of surfactant optimization in the design of flaw detectors, and further verify the innovativeness of the technical solution of the present invention in solving the penetration problem.

[0125] Experiment 4: Image clarity test Experimental description: Purpose: The imaging effect of the flaw detection agent in crack detection is tested, and the influence of the dispersion and fixation of the developer on the imaging performance is evaluated by the imaging contrast.

[0126] Experimental materials and equipment: Standard crack test plate (crack width 10μm, depth 1mm, material: high temperature alloy).

[0127] Samples: Example 3, Comparative Example 4.

[0128] High temperature furnace (temperature control range: 400℃±2℃).

[0129] Optical microscope (magnification 100).

[0130] Image processing and analysis software (for grayscale contrast analysis).

[0131] Experimental steps: Crack test plate treatment: Take 3 standard crack test plates, put them into a high-temperature furnace, set the temperature to 400℃, and keep the temperature constant for 1 hour to simulate the high-temperature crack environment. Take them out and cool them to room temperature for use.

[0132] Imaging operation: The flaw detection agent samples of Example 3 and Comparative Example 4 were sprayed on the surface of the crack test plates respectively, with a coating amount of 2 mL per test plate to ensure that the crack area was completely covered with the flaw detection agent.

[0133] The developing time is set to 10 minutes. After the penetration and development of the flaw detection agent are completed, use a clean cloth to gently wipe off the excess flaw detection agent on the surface.

[0134] Imaging observation and data recording: An optical microscope was used to observe the imaging effect of the crack area, and the imaging images were taken. The grayscale values ​​of the crack area and the background area were calculated using image processing and analysis software.

[0135] The imaging contrast is calculated by dividing the grayscale of the crack area by the grayscale of the background area; Each sample was measured 3 times and the average imaging contrast was calculated.

[0136] Experimental data: Experimental summary: The test results of the imaging contrast show that the imaging effect of Example 3 is significantly better than that of Comparative Example 4. In Example 3, the developer particle size distribution is uniform, and it is fixed deep in the crack by the high-temperature resistant polyamide, ensuring the complete appearance of the crack morphology. This high imaging contrast effect comes from the stability of the developer in the crack. The introduction of the high-temperature resistant polyamide forms a physical fixing layer, which limits the movement of the developer particles in a high-temperature environment, so that its imaging performance is not affected by temperature fluctuations. In Comparative Example 4, due to the lack of fixing materials, the developer particles are loosely distributed in the cracks, resulting in a low grayscale value in the imaging area and a significantly insufficient contrast.

[0137] Through microscopic observation, the crack image in Example 3 is clear and the crack outline is clearly discernible, which is closely related to the synergistic effect of the developer dispersibility and permeability. The surface-modified developer forms a uniform distribution in the crack, so that the grayscale difference between the imaged area and the background area is significant. In Comparative Example 4, the crack image is discontinuous, the developer is mostly concentrated in the crack entrance area, and there is a lack of sufficient particle filling in the deep cracks. This result further verifies the role of high-temperature resistant polyamide in the control of developer distribution, which has an irreplaceable function for the internal crack image effect.

[0138] The difference in imaging performance is also affected by the stability of the flaw detector particles in the crack. The flaw detector developer of Example 3 has stronger adhesion in the crack, while the developer in Comparative Example 4 lacks polyamide fixation, and some imaging particles are separated from the crack wall due to the influence of high temperature thermal vibration and capillary pressure. This particle detachment phenomenon greatly reduces the imaging performance of Comparative Example 4, resulting in discontinuous crack imaging effect and high background grayscale. These experimental results show that the design in Example 3 can significantly improve the imaging effect of crack detection and show stronger adaptability in high temperature and complex environments.

[0139] Experiment 5: High temperature long-term stability test Experimental description: Purpose: The long-term stability of penetrant flaw detection agents in high temperature environments was tested, and the effects of different preparation processes and developer dispersion methods on viscosity retention and chemical stability were evaluated.

[0140] Experimental materials and equipment: Samples: Example 1, Example 3, Comparative Example 6.

[0141] High temperature sealed container (temperature controllable to 400℃±5℃).

[0142] Rotational viscometer (accuracy ±0.1 mPa·s).

[0143] Transparent sample bottle (high temperature resistant material).

[0144] Quantitative balance (accuracy ±0.01g).

[0145] Experimental steps: Sample preparation: 10 mL of the flaw detection agent samples of Example 1, Example 3 and Comparative Example 6 were taken respectively, put into clean, dry high-temperature sample bottles, sealed and marked as A1 (Example 1), A3 (Example 3) and C6 (Comparative Example 6).

[0146] High temperature storage: Place the sample bottle in a high temperature sealed container, set the ambient temperature to 400°C, and maintain a constant temperature. Record the start time and perform interval tests on the sample.

[0147] Viscosity test: Every 2 hours, take 1 mL of sample, test the viscosity with a rotational viscometer, and record the measured value. Seal the remaining sample in the sample bottle and return it to the high temperature environment. The total test time is 24 hours.

[0148] Appearance observation: After each test, observe whether the sample color changes significantly (from transparent to turbid, phase separation or precipitation, etc.). At the same time, record the change in sample mass (mass loss caused by evaporation or decomposition).

[0149] Experimental data: Experimental summary: Examples 1 and 3 showed high stability under high temperature environment. The viscosity values ​​of both increased only slightly within 24 hours, while the viscosity change of comparative example 6 was significantly larger, and the sample had phase separation in the later stage. This result directly reflects the key influence of the dispersion treatment of the developer and the selection of the solvent system on the performance of the flaw detection agent under high temperature environment. In Example 3, because the developer is fixed by high temperature resistant polyamide, its stability is better, while Example 1 relies on the optimized high temperature solvent matrix to maintain chemical stability.

[0150] The data of Comparative Example 6 clearly shows the influence of ultrasonic dispersion parameters on the dispersion quality of the developer. Since the ultrasonic frequency and power are not strictly controlled, the developer is unevenly distributed in the high-temperature solvent matrix, resulting in particle agglomeration at high temperatures in the later stage. The agglomeration effect not only affects the viscosity of the flaw detection agent, but also aggravates the uneven evaporation between the components, causing mass loss and phase separation. This defect is particularly evident in the evaporation rate and viscosity changes of Comparative Example 6.

[0151] The details of the color change further reveal the difference in chemical stability. Example 3 showed slight yellowing in a high temperature environment, indicating that the thermal oxidation effect of high temperature on the flaw detection agent was relatively limited. In contrast, Comparative Example 6 gradually became turbid in the later stage of the experiment, and the sample phase separated, indicating a lack of effective interfacial bonding between its developer particles and the solvent matrix. This is closely related to the introduction of high temperature resistant polyamide. In Example 3, the polyamide not only fixed the developer, but also stabilized the thermodynamic properties of the entire liquid phase system, effectively suppressing the adverse effects of component decomposition and diffusion at high temperatures. These experimental data and phenomena once again demonstrate the unique advantages of the developer dispersion and fixation technical solutions in the embodiments in high temperature application scenarios.

[0152] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A penetrant flaw detector for stable imaging in a high temperature environment, characterized in that: Includes the following components: Aromatic ether solvent: 65 to 80 parts; Cosolvent: 8 to 12 parts; Nano titanium dioxide developer: 4 to 8 parts; Fluorinated surfactant: 2 to 5 parts; High temperature resistant polyamide: 3 to 6 parts.

2. The penetrant flaw detection agent for stable imaging in a high temperature environment according to claim 1, characterized in that: The aromatic ether solvent is biphenyl ether or diphenyl ether, and its boiling point ranges from 250°C to 270°C.

3. The penetrant flaw detection agent for stable imaging in a high temperature environment according to claim 1, characterized in that: The co-solvent is triethylene glycol monoether, and its boiling point ranges from 250°C to 280°C.

4. The penetrant flaw detection agent for stable imaging in a high temperature environment according to claim 1, characterized in that: The particle size of the nano titanium dioxide developer is 30nm-50nm and is modified by a silane coupling agent.

5. The penetrant flaw detection agent for stable imaging in a high temperature environment according to claim 1, characterized in that: The fluorinated surfactant is a potassium hexafluorophosphate derivative, and its molecular structure comprises a hydrophilic group and a fluorinated chain segment.

6. The penetrant flaw detection agent for stable imaging in a high temperature environment according to claim 1, characterized in that: The molecular weight of the high temperature resistant polyamide is 10,000 g / mol to 20,000 g / mol, and the glass transition temperature is 260° C. to 280° C.

7. A method for preparing a penetrant flaw detector for stable imaging in a high temperature environment, according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Add an aromatic ether solvent into a stirring kettle at a temperature of 100°C to 130°C, and control the stirring speed to 400rpm to 600rpm; S2, adding a co-solvent to the aromatic ether solvent, stirring for 20 min to 40 min to form a uniform solvent matrix; S3, adding a portion of nano titanium dioxide developer to the solvent matrix, using an ultrasonic disperser with a frequency of 35kHz to 45kHz and a power of 400W to 600W to disperse for 40min to 60min to obtain a mixture A; S4. Add a fluorinated surfactant to mixture A at 50°C to 70°C and stir for 20min to 30min to obtain mixture B; S5. Add the high temperature resistant polyamide to the mixture B at 60°C to 80°C, and stir for 30min to 50min using a high-speed stirrer at a speed of 5000rpm to 7000rpm to obtain a final mixture; S6. The final mixture is homogenized by a high shear mixer with a rotation speed of 6000 rpm to 8000 rpm for 40 min to 60 min, and the penetrant flaw detection agent is obtained after cooling to room temperature.

8. The method for preparing a penetrant flaw detection agent for stable imaging in a high temperature environment according to claim 7, characterized in that: In the step S3, the particle size of the nano-titanium dioxide developer is controlled within the range of 30 nm to 50 nm by dynamic light scattering detection, and the coefficient of variation of the particle size distribution is less than 5%.

9. The method for preparing a penetrant flaw detection agent for stable imaging in a high temperature environment according to claim 7, characterized in that: In the step S4, the concentration of the fluorinated surfactant added is controlled to be 0.008 mol / L to 0.015 mol / L.

10. The method for preparing a penetrant flaw detection agent for stable imaging in a high temperature environment according to claim 7, characterized in that: In the step S6, after high shear homogenization treatment, the component distribution error of the penetrant flaw detection agent is less than 3%.

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