Preparation method of three-dimensional surface high-density non-communicated phosphorescent speckle coating

Abstract

The invention discloses a preparation method of a three-dimensional surface high-density non-communicated phosphorescent speckle coating, and relates to the technical field of temperature and strain synchronous measurement, and the preparation method comprises the following steps: step 1, applying a surface modifier on the surface of a substrate to form a low surface modification layer so as to reduce surface energy; 2, spraying a water-based phosphorescent coating layer on the modified layer, wherein the coating comprises a phosphorescent material and a binder; 3, the sprayed phosphorescent coating is subjected to high-temperature curing to form an island-shaped phosphorescent speckle coating, the feature size of a non-communicated island-shaped structure of the island-shaped phosphorescent speckle coating is 5-5 mm, the interval is 1-1 mm, and the coverage rate is larger than 70%. Through surface energy regulation and control, the water-based phosphorescent coating can be induced to spontaneously form an intensive random island-shaped structure. The prepared phosphorescent speckles are high in surface coverage rate, the temperature response characteristic of the phosphorescent material can be completely reserved, and sufficient gray scale characteristics can be effectively provided for a digital image correlation method due to the randomness of the island-shaped speckles and the high contrast ratio of the patterns, so that the strain measurement requirement is met.

Description

Technical Field

[0001] This invention relates to the field of simultaneous temperature and strain measurement technology, specifically a method for preparing a three-dimensional surface high-density non-connected phosphorescent speckle coating. Background Technology

[0002] Three-dimensional temperature-strain synchronous measurement is a key technology for characterizing the behavior and safety performance of materials and components under complex operating conditions, especially in high-temperature equipment such as gas turbines and aero-engines, where the operating environment is characterized by extreme features such as high temperature, high pressure, and strong corrosion. Temperature and strain are highly coupled, necessitating precise synchronous measurement methods to provide data support for equipment operation monitoring and performance evaluation. Existing technologies face the following challenges:

[0003] Traditional contact-type temperature-strain measurement technology can only achieve point measurement. In complex scenarios such as high temperature and rotation, the contact points are prone to rapid aging, resulting in decreased measurement accuracy, shortened service life, and difficulty in adapting to harsh environments such as strong corrosion.

[0004] While the combination of infrared thermometry and digital image correlation (DIC) can achieve strain measurement, the accuracy of infrared thermometry is easily affected by background radiation, requires knowledge of the target emissivity, and the zenith angle has a significant impact on the measurement accuracy of inclined or distant surfaces, making it particularly unsuitable for large curvature three-dimensional surfaces. At the same time, the temporal and spatial resolution of infrared cameras is much lower than that of ordinary cameras, which limits the spatiotemporal accuracy of the measurement.

[0005] To overcome the aforementioned challenges, phosphorescence thermometry (PT) is combined with digital image correlation (DIC) strain measurement technology, providing a key method for achieving simultaneous temperature-strain measurement in complex environments. Phosphorescence-based thermometry enables high-precision measurement of temperature across the entire field; changes in the luminescence intensity or lifetime of the phosphorescent material can directly reflect the temperature distribution of the measured surface. Meanwhile, digital image correlation, a mature non-contact measurement method, can accurately acquire full-field displacement and strain information by tracking the grayscale changes of surface speckles, making it particularly suitable for the three-dimensional morphology reconstruction and deformation analysis of complex curved surfaces. Combining phosphorescence thermometry with DIC overcomes the limitations of harsh environments, enabling simultaneous measurement of three-dimensional temperature and strain information of complex structures under adverse conditions.

[0006] However, the synergistic application of phosphorescent thermometry (PT) and digital image correlation (DIC) still faces technical obstacles. PT relies on the phosphorescent properties of the overall coating to achieve full-field temperature measurement, while DIC needs to calculate strain using the grayscale characteristics of sparse speckles. If the phosphorescent material is made into speckles, the temperature measurement will be incomplete due to insufficient signal coverage; if the overall coating is retained, the grayscale differences required by DIC are lacking, resulting in a significant decrease in strain measurement accuracy. The technical conflict between the two restricts the application of simultaneous measurement in high-temperature environments.

[0007] Furthermore, the speckle pattern of the spraying method disclosed in patent CN110926356B relies on the properties of iron-aluminum spinel and is only applicable to shaped refractory materials, with limited applicability to complex curved surfaces and other materials; the masking method disclosed in patent CN110793453A has a complex process, requires the prefabrication of a two-dimensional template, and the use of laser engraving to prepare the template results in low speckle density, and the template is difficult to fit three-dimensional surfaces that cannot be unfolded into a two-dimensional plane, resulting in poor adaptability to unknown three-dimensional surfaces; the dot coating method of patent CN115872742B relies on manual dripping, which is inefficient and cannot accurately control the size, spacing and density of speckles, making it unsuitable for the preparation of large-area samples.

[0008] Therefore, existing technologies struggle to fabricate phosphorescent speckle coatings with both high coverage and non-connectivity on three-dimensional surfaces, failing to simultaneously meet the requirements of full-field PT temperature measurement and full-field DIC strain measurement. Consequently, we propose a method for fabricating high-density, non-connectivity phosphorescent speckle coatings on three-dimensional surfaces to address the aforementioned problems. Summary of the Invention

[0009] The purpose of this invention is to provide a method for preparing a high-density non-connected phosphorescent speckle coating on a three-dimensional surface, so as to solve the problem mentioned in the background art that it is difficult to prepare phosphorescent speckles with both high coverage and non-connected characteristics on a three-dimensional surface, thus failing to meet the requirements of PT full-field temperature measurement and DIC full-field strain measurement at the same time.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A method for preparing a three-dimensional surface high-density non-connected phosphorescent speckle coating includes the following steps:

[0012] Step 1: Apply a surface modifier to the substrate surface to form a low surface modification layer to reduce surface energy;

[0013] Step 2: Spray a water-based phosphorescent coating layer onto the modified layer. The coating contains phosphorescent materials and binders.

[0014] Step 3: The sprayed phosphorescent coating is cured at high temperature to form an island-shaped phosphorescent speckle coating. The characteristic size of the non-connected island structure is 5μm-5mm, the spacing is 1μm-1mm, and the coverage is greater than 70%.

[0015] Among them, the phosphorescent coating synchronously responds to temperature and strain, and is used for temperature-strain coupling measurement in high-temperature environments, or synchronous temperature-strain measurement during dynamic deformation processes.

[0016] Preferably, in step one, the matrix material is a metallic material, an inorganic non-metallic material, or a composite material, and the matrix is ​​a three-dimensional curved surface.

[0017] Preferably, in step one, the surface modifier includes one or more mixtures of fluorinated surfactants, organosilicon compounds, fluorinated polymer solutions, and hydrocarbon low surface energy substances.

[0018] Preferably, in step one, the surface modifier is applied by one of the following methods: wiping, spraying, spin coating, or dip coating.

[0019] Preferably, in step two, the mass ratio of the phosphorescent material to the binder is 1:1-10, and the phosphorescent material includes one of Mg4FGeO6:Mn, Y2O3:Eu, YAG:Dy, YSZ:Eu, Y2O3:Dy, and ZnO:Zn, with a particle size of 0.5-50μm.

[0020] Preferably, in step two, the coating thickness is 1-200 μm, and in step three, the curing temperature is 80-200℃.

[0021] Preferably, the size and coverage of the island structure are achieved by adjusting the type of surface modifier; spraying pressure, nozzle diameter, spraying distance; and the ratio of phosphorescent material to binder.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] This invention induces the spontaneous formation of dense, random island-like structures in water-based phosphorescent coatings through surface energy modulation. The resulting phosphorescent speckle pattern exhibits high surface coverage, fully preserving the temperature response characteristics of the phosphorescent material. Furthermore, the randomness of the island-like speckle pattern and its high contrast effectively provide sufficient grayscale features for digital image correlation methods, thus meeting the requirements for strain measurement.

[0024] Furthermore, the inhibitory effect of low surface energy modified surfaces on coating spread, combined with the independent stable state formed by the surface tension difference between droplets, lays a solid foundation for the precise control of speckle structure. Moreover, this invention has significant advantages such as simple preparation process, low cost, and applicability to any three-dimensional geometric surface, and has good applicability in temperature-strain coupling measurements under high-temperature environments.

[0025] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the coating preparation process of the present invention.

[0027] Figure 2 This is a physical image of the phosphorescent speckle pattern of the present invention under excitation.

[0028] Figure 3 These are examples of speckle patterns of different densities achieved by controlling parameters according to the present invention. Among them: (a) is Example 1; (b) is Example 2; (c) is Example 3.

[0029] Figure 4 The three-dimensional surface temperature-strain results are obtained through existing phosphorescent speckle measurements. Wherein: (a) is the three-dimensional temperature field; (b) is the three-dimensional strain field. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] Material preparation: Silicone oil was selected as the surface modifier, Mg4FGeO6:Mn (MFG) with a particle size of 0.5-50μm was selected as the phosphorescent material, HPC (ZYP Coatings, USA) was selected as the binder, and the substrate sample was a 0.2mm thick 304 stainless steel sheet.

[0033] Preparation of phosphorescent coating: Mix MFG powder, HPC and deionized water in a mass ratio of 1:3:2, stir thoroughly and ultrasonically vibrate for 1 hour until homogeneous.

[0034] As attached Figure 1 , 2 The preparation steps of the phosphorescent speckle coating are shown below:

[0035] 1. Clean the surface of the substrate sample sequentially with distilled water and anhydrous ethanol, and then dry it thoroughly;

[0036] 2. Apply silicone oil evenly to the surface of the substrate sample using a wiping method for modification, and let it stand for 30 minutes to allow the surface modifier to fully bond with the substrate sample;

[0037] 3. Use an airbrush to evenly spray the phosphorescent coating onto the surface of the substrate sample. The airbrush diameter is 0.5 mm, the spraying pressure is 0.4 MPa, and the distance between the airbrush and the sample is 50 cm.

[0038] 4. Place the substrate sample in a drying oven at 80°C for 2 hours, and then cure it at 150°C for 5 hours to complete the coating preparation.

[0039] The coating thickness is 100μm, the average size of the island structure is 600μm, and the surface coverage is 75%.

[0040] Test: The bottom of the substrate sample was fixed, and a 500℃ hot jet was used to impact the substrate sample from an oblique angle above. The measurement results showed that the temperature and strain were highest in the jet impact area, and the strain distribution was consistent with the temperature distribution, as shown in the attached figure. Figure 2 (a) and appendix Figure 4 As shown.

[0041] Example 2

[0042] Material preparation: The surface modifier used is the same silicone oil as in Example 1;

[0043] Phosphorescent material: Y2O3:Eu is selected, with a particle size of 5-40μm;

[0044] Adhesive: Same as in Example 1, HPC (ZYP Coatings, USA) was selected.

[0045] Substrate sample: Same as in Example 1, a 0.2mm thick 304 stainless steel sheet.

[0046] Preparation of phosphorescent coating: Following the same ratio as in Example 1, Y2O3:Eu powder, HPC and deionized water are mixed at a mass ratio of 1:3:1. After thorough stirring, the mixture is ultrasonically vibrated for 1 hour to ensure uniform mixing and the formation of a stable water-based phosphorescent coating.

[0047] Preparation steps of phosphorescent speckle coating:

[0048] 1. Clean the surface of the substrate sample sequentially with distilled water and anhydrous ethanol, and then dry it thoroughly;

[0049] 2. Apply silicone oil using a spraying method and let it stand for 30 minutes to allow the surface modifier to fully bond with the substrate sample;

[0050] 3. Use an airbrush to evenly spray the phosphorescent coating onto the surface of the substrate sample. The airbrush diameter is 0.5 mm, the spraying pressure is 0.4 MPa, and the distance between the airbrush and the sample is 30 cm.

[0051] 4. Place the sample in a drying oven at 80℃ for 2 hours, and then cure it at 150℃ for 5 hours to complete the coating preparation.

[0052] The coating thickness was 200 μm; the average size of the island-like structures was 300 μm; the test results are attached. Figure 2 As shown in (b) of the diagram.

[0053] Example 3

[0054] Material preparation: The surface modifier used was polytetrafluoroethylene (PTFE) solution; the phosphorescent material used was YAG:Dy; the binder was the same as in Example 1, using HPC (ZYP Coatings, USA); the substrate sample was 6061 aluminum.

[0055] Preparation of phosphorescent coating: Mix YAG:Dy powder, HPC and deionized water at a mass ratio of phosphorescent material to binder of 1:3, stir for 30 min and then sonicate for 1.5 h to form a uniformly dispersed water-based phosphorescent coating.

[0056] Preparation steps of phosphorescent speckle coating:

[0057] 1. Clean the surface of the substrate sample sequentially with distilled water and anhydrous ethanol, and then dry it thoroughly;

[0058] 2. Surface modification is achieved by spraying PTFE solution with an airbrush;

[0059] 3. Use an airbrush to evenly spray the phosphorescent coating onto the surface of the substrate sample. The airbrush diameter is 0.5 mm, the spraying pressure is 0.5 MPa, and the distance between the airbrush and the sample is 30 cm.

[0060] 4. Place the substrate sample in a drying oven at 80°C for 2 hours, and then cure it at 180°C for 5 hours to complete the coating preparation.

[0061] The coating thickness was 50 μm, and the average size of the island-like structures was 400 μm; the test results are attached. Figure 2 As shown in (c) in the figure.

[0062] The embodiments of the present invention are given for the purposes of illustration and description. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made by those skilled in the art to the above embodiments within the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a three-dimensional surface high-density non-connected phosphorescent speckle coating, characterized in that, Includes the following steps: Step 1: Apply a surface modifier to the substrate surface to form a low surface modification layer to reduce surface energy; Step 2: Spray a water-based phosphorescent coating layer onto the modified layer. The coating contains phosphorescent materials and binders. Step 3: The sprayed phosphorescent coating is cured at high temperature to form an island-shaped phosphorescent speckle coating. The characteristic size of the non-connected island structure is 5μm-5mm, the spacing is 1μm-1mm, and the coverage is greater than 70%. Among them, the phosphorescent coating synchronously responds to temperature and strain, and is used for temperature-strain coupling measurement in high-temperature environments, or synchronous temperature-strain measurement during dynamic deformation processes.

2. The method for preparing a three-dimensional surface high-density non-connected phosphorescent speckle coating according to claim 1, characterized in that: In step one, the substrate is a metallic material, an inorganic non-metallic material, or a composite material, and the substrate is a three-dimensional curved surface.

3. The method for preparing a three-dimensional surface high-density non-connected phosphorescent speckle coating according to claim 1, characterized in that: In step one, the surface modifier includes one or more mixtures of fluorinated surfactants, organosilicon compounds, fluorinated polymer solutions, and hydrocarbon low surface energy substances.

4. The method for preparing a three-dimensional surface high-density non-connected phosphorescent speckle coating according to claim 1, characterized in that: In step one, the surface modifier can be applied by one of the following methods: wiping, spraying, spin coating, or dip coating.

5. The method for preparing a three-dimensional surface high-density non-connected phosphorescent speckle coating according to claim 1, characterized in that: In step two, the mass ratio of the phosphorescent material to the binder is 1:1-10. The phosphorescent material includes one of Mg4FGeO6:Mn, Y2O3:Eu, YAG:Dy, YSZ:Eu, Y2O3:Dy, and ZnO:Zn, and the particle size of the phosphorescent material is 0.5-50μm.

6. The method for preparing a three-dimensional surface high-density non-connected phosphorescent speckle coating according to claim 1, characterized in that: In step two, the coating thickness is 1-200 μm, and in step three, the curing temperature is 80-200℃.

7. The method for preparing a three-dimensional surface high-density non-connected phosphorescent speckle coating according to claim 1, characterized in that: The size and coverage of the island structure are achieved by adjusting the type of surface modifier, spraying pressure, nozzle diameter, spraying distance, and the ratio of phosphorescent material to binder.

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