High near-infrared reflective yellow inorganic pigment, and preparation method and application thereof

Abstract

This invention discloses a high near-infrared reflectance yellow inorganic pigment, its preparation method, and its application, belonging to the field of inorganic pigment technology. The invention uses La, Y, and Cr sources as raw materials, and formulates them according to stoichiometric ratios. A LaY pigment with a perovskite structure is synthesized via a sol-gel method. 1‑X Cr X O3 (0)

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic pigments, and particularly relates to a high near-infrared reflective yellow inorganic pigment, its preparation method and application. Background Art

[0002] Pigments are important functional substances that can endow materials with colors and have decorative and protective functions. They are widely used in fields such as coatings, ceramics, building materials, etc. According to chemical composition, they can be divided into organic pigments and inorganic pigments. Organic pigments have advantages such as bright colors and strong coloring power, but their heat resistance, weather resistance and chemical stability are poor, and they are prone to decomposition or fading in high-temperature, strong ultraviolet irradiation and acid-base environments, thus limiting their application in outdoor and high-durability fields. In contrast, inorganic pigments show a broader application prospect in fields such as building energy conservation, functional coatings and environmentally friendly materials due to their excellent thermal stability, chemical stability and weather resistance. In recent years, with the development of building energy conservation and thermal management technologies, "cold pigments" with high sunlight reflection ability, especially high near-infrared reflection performance, have become a research hotspot. Such pigments can effectively reflect near-infrared radiation in sunlight, reduce the surface temperature of materials, thereby reducing energy consumption and alleviating the urban heat island effect.

[0003] At present, common yellow high-performance near-infrared reflective inorganic pigments still have some limitations: some systems contain toxic heavy metals (such as lead chromate yellow), with poor environmental compatibility; the reflectivity and chromaticity stability need to be further improved; the synthesis cost is relatively high or the weather resistance is insufficient. Therefore, developing a rare-earth-based inorganic pigment with excellent comprehensive chromaticity performance, high chemical stability and high near-infrared reflection performance can meet people's needs for environmentally friendly non-toxic yellow pigments and expand the application fields of yellow inorganic pigments. Summary of the Invention

[0004] The present invention discloses a preparation method and application of a high near-infrared reflective yellow inorganic pigment. The inorganic pigment prepared by the present invention is a rare-earth-based inorganic pigment with excellent comprehensive chromaticity performance, high chemical stability and high near-infrared reflection performance.

[0005] (1) The present invention provides a high near-infrared reflective yellow inorganic pigment, and the chemical formula of the high near-infrared reflective yellow inorganic pigment is LaY ,

[0007] ,

[0006] , Cr X O3, where 0 < x ≤ 0.10. Cr(III) is a doping element, and x represents the doping molar amount of Cr(III).

[0006] By changing the doping molar amount of Cr(III), the color of the pigment can be changed. As the doping molar amount of Cr(III) increases, the color of the pigment changes from light yellow to dark yellow. [[ID=​The near-infrared reflectance of the high near-infrared reflective yellow inorganic pigment at 895 nm is 67.561% - 75.73%, and at 1350 nm is 78.166% - 80.765%.

[0008] When x = 0.025, the chemical formula of the yellow inorganic pigment is LaY 0.975 Cr 0.025 O3, and its near-infrared reflectance at 895 nm is 71.498%, and at 1350 nm is 79.317%.

[0009] When x = 0.05, the chemical formula of the yellow inorganic pigment is LaY 0.95 Cr 0.05 O3, and its near-infrared reflectance at 895 nm is 75.73%, and at 1350 nm is 80.765%.

[0010] When x = 0.075, the chemical formula of the yellow inorganic pigment is LaY 0.925 Cr 0.075 O3, and its near-infrared reflectance at 895 nm is 68.919%, and at 1350 nm is 78.166%.

[0011] When x = 0.1, the chemical formula of the yellow inorganic pigment is LaY 0.925 Cr 0.075 O3, and its near-infrared reflectance at 895 nm is 67.561%, and at 1350 nm is 78.434%.

[0012] The near-infrared reflectance of the high near-infrared reflective yellow inorganic pigment at 895 nm is 67.561% - 75.73%, and at 1350 nm is 78.166% - 80.765%.

[0013] (II) The present invention provides a preparation method of a high near-infrared reflective yellow inorganic pigment. Using La source, Y source and Cr source as raw materials, proportioned according to the stoichiometric ratio, and synthesized by the sol-gel method to obtain LaY 1-X Cr X O3 (0 < x ≤ 0.10) pigment.

[0014] The specific preparation method is as follows:

[0015] S1. Using Cr source, La source, Y source as raw materials, mixed according to the stoichiometric ratio of each element in the chemical formula LaY 1-X Cr X O3, and accurately weighing the raw materials with an electronic balance;

[0016] S2. Putting the weighed powder raw materials in S1 into a beaker, adding deionized water, and using a magnetic stirrer

[0017] Stir until a clear solution is obtained, then add citric acid, glucose, and acrylamide in sequence;

[0018] S3. Set the temperature of the magnetic stirrer, stir for a period of time, and put the resulting gel into an oven to dry for a period of time to obtain the precursor;

[0019] S4. Place the dried precursor from S3 into a mortar and grind it manually. Then pour the ground powder into a crucible.

[0020] S5. Place the crucible from S4 into a muffle furnace and perform high-temperature sintering in the muffle furnace according to the heating curve to obtain a single-phase yellow inorganic pigment with high near-infrared reflectance.

[0021] Furthermore, in S1, the La source is provided by a La-containing compound. For example, it is provided by at least one of La-containing carbonates, oxides, chlorides, and nitrates.

[0022] Furthermore, in S1, the Y source is provided by a compound containing the element Y. For example, it is provided by at least one of carbonates, oxides, chlorides, and nitrates containing the element Y.

[0023] Furthermore, in S1, the Cr source is provided by a Cr-containing compound. For example, it is provided by at least one of Cr-containing carbonates, oxides, chlorides, and nitrates.

[0024] Furthermore, in S1, the raw material quality error is controlled within ±0.0005g.

[0025] Furthermore, in S2, after adding deionized water, citric acid, glucose, and acrylamide, stir for 10-30 minutes with a magnetic stirrer speed of 700-900 r / min.

[0026] Furthermore, in S3, the temperature of the magnetic stirrer is set to 60℃-80℃, the stirring time is 4-5h, and the speed of the magnetic stirrer is 700-900 r / min.

[0027] Furthermore, in S3, the drying time in the oven is 10-14 hours, and the oven temperature is 100℃-120℃.

[0028] Furthermore, in S4, the grinding time is 15-30 minutes.

[0029] Furthermore, in S5, the conditions for the muffle furnace are set as follows:

[0030] The heating rate is 5-10℃ / min, raising the temperature from room temperature to 800℃-1000℃, holding for 5-6 hours in an air atmosphere; then cooling is carried out at a cooling rate of 5-10℃ / min.

[0031] Beneficial effects:

[0032] (1) The yellow inorganic pigment prepared by this invention can change its color from light yellow to dark yellow by changing the molar amount of Cr(III) doping. The brightness L* value of the yellow inorganic pigment decreases from 88.17 to 77.58 with the increase of dopant ion content, the a* value decreases from -1.56 to -2.02 with the increase of dopant ion content, and then increases from -2.02 to 0.04, while the b* value increases from 23.31 to 39.76 with the increase of dopant ion content, showing excellent color rendering performance and overall color purity.

[0033] (2) The yellow inorganic pigment prepared by this invention is particularly suitable for building exterior wall energy-saving materials, coatings, plastics, vehicles, ship decks and other fields. It is of great significance for reducing building energy consumption and alleviating the urban heat island effect, and has broad prospects for industrial application.

[0034] (3) The yellow inorganic pigment prepared by the present invention is obtained by the sol-gel method. The preparation process is simple, the equipment requirements are low, the raw materials are widely available and the cost is low, making it suitable for large-scale production.

[0035] (4) The yellow inorganic pigment prepared by the present invention has a single perovskite orthorhombic crystal phase structure, no impurity phase is generated, the crystal structure is stable, and Cr(III) can successfully enter the crystal lattice to form a solid solution.

[0036] (5) The yellow inorganic pigment prepared by the present invention has excellent chemical and thermal stability, and can maintain a stable crystal phase structure and comprehensive color performance in acid, alkali and water environments.

[0037] (6) The yellow inorganic pigment prepared by this invention does not require the use of toxic heavy metals and highly polluting organic reagents during the preparation process. It is environmentally friendly, has little harm to the human body, and is in line with the development direction of green chemistry.

[0038] (7) The inorganic pigment material prepared by the present invention has the structural characteristics of single crystal phase and high purity.

[0039] (8) The pigment exhibits a saturated and pure yellow color in the visible light band (380-780 nm), with excellent overall color performance; at the same time, it has significant solar reflectance characteristics in the near-infrared band (780-2500 nm), with an average near-infrared reflectance greater than 70%. Attached Figure Description

[0040] Figure 1 The XRD patterns of the high near-infrared reflectance yellow inorganic pigments obtained by the preparation method of the present invention in Examples 1 to 4 are compared with those in Comparative Example 1.

[0041] Figure 2 The UV-Vis-NIR spectra of the high near-infrared reflectance yellow inorganic pigments obtained by the preparation method of the present invention in Examples 1 to 4 are compared with those of Comparative Example 1.

[0042] Figure 3 The diagram shows the NIR solar reflectance spectra of the high near-infrared reflectance yellow inorganic pigments obtained by the preparation method of the present invention in Examples 1 to 4 and the comparative example 1.

[0043] Figure 4 This is a schematic diagram of the optical bandgap of the high near-infrared reflectance yellow inorganic pigments obtained by using the preparation method of the present invention in Examples 1 to 4.

[0044] Figure 5 The diagram shows the high near-infrared reflectance yellow inorganic pigments obtained by the preparation method of the present invention in Examples 1 to 4 and the pigment in Comparative Example 1.

[0045] Figure 6 This is a schematic SEM image of the high near-infrared reflectance yellow inorganic pigment obtained in Example 2 using the preparation method of the present invention.

[0046] Figure 7 This is a schematic diagram of the EDS spectrum of the high near-infrared reflectance yellow inorganic pigment obtained in Example 2 using the preparation method of the present invention.

[0047] Figure 8 This is a schematic diagram of the TG spectrum of the high near-infrared reflectance yellow inorganic pigment obtained by Example 2 using the preparation method of the present invention, compared with that of Comparative Example 1.

[0048] Figure 9 This is a schematic XPS image of the high near-infrared reflectance yellow inorganic pigment obtained in Example 2 using the preparation method of the present invention. Detailed Implementation

[0049] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. The embodiments are merely examples of the present invention and are not intended to limit the invention. However, the scope of protection of the present invention is not limited to the following embodiments. The raw materials and reagents used in the embodiments are all commercially available products.

[0050] Example 1: Preparation of inorganic pigment LaY 0.975 Cr 0.025 O3

[0051] 1) According to LaY 0.975 Cr 0.025The chemical formula of O3 is given. La(NO3)3·6H2O (0.333g), Y(NO3)3·6H2O (0.287g), and Cr(NO3)3·9H2O (0.0077g) are weighed using an electronic analytical balance according to the stoichiometry. The allowable error in mass is ±0.0005g.

[0052] 2) Add the weighed powdered raw materials to a beaker, add 20 ml of deionized water, and stir on a magnetic stirrer for 10 min. After the solution becomes clear, add 0.6472 g of citric acid as a complexing agent, and then stir for 30 min. Add 0.5 g of glucose to further improve the dispersibility of the system, and stir for 30 min. Then add 0.437 g of acrylamide and stir for 30 min. The magnetic stirrer speed is 800 r / min.

[0053] 3) Heat the magnetic stirrer to 80℃ and stir for 4 hours to form a gel. Then, place it in a vacuum oven and dry at 120℃ for 12 hours to obtain the precursor. The magnetic stirrer speed is 800 r / min.

[0054] 4) Then put the dried precursor into a crucible and grind it into powder by hand for 30 minutes.

[0055] 5) Place the crucible in a muffle furnace and raise the temperature of the muffle furnace to 1000℃ in an air atmosphere at a heating rate of 5℃ / min. Hold the temperature at 1000℃ for 5 hours. After holding, cool the temperature to room temperature at a cooling rate of 5℃ / min. Finally, take out the sample, grind it, and obtain 0.21g of stable yellow inorganic pigment.

[0056] Example 2: Preparation of inorganic pigment LaY 0.5 Cr 0.05 O3

[0057] By adjusting the amount of raw materials and using the sol-gel method, LaY was synthesized. 0.5 Cr 0.05 O3 was synthesized using the same process as in Example 1.

[0058] Example 3: Preparation of inorganic pigment LaY 0.925 Cr 0.075 O3

[0059] By adjusting the amount of raw materials and using the sol-gel method, LaY was synthesized. 0.5 Cr 0.05 O3 was synthesized using the same process as in Example 1.

[0060] Example 4: Preparation of Inorganic Pigment LaY 0.9 Cr 0.1 O3

[0061] By adjusting the amount of raw materials and using the sol-gel method, LaY was synthesized. 0.5 Cr 0.05 O3 was synthesized using the same process as in Example 1.

[0062] Table 1 shows the preparation parameters for Examples 1-4.

[0063] Table 1. Preparation parameters of Examples 1-4

[0064]

[0065] Comparative Example 1: Preparation of LaYO3 Inorganic Pigment

[0066] The chemical formula LaYO3, i.e., the base pigment without Cr, was synthesized using the sol-gel method. The synthesis process was the same as in Example 1, except for the amount of raw materials used: La(NO3)3·6H2O (0.333g), Y(NO3)3·6H2O (0.294g), and Cr(NO3)3·9H2O was not added. Finally, a white inorganic pigment was obtained.

[0067] Comparative Example 2: Preparation of Inorganic Pigments by Changing Calcination Temperature

[0068] Except for the calcination temperature, the other preparation steps were the same as in Example 1. The obtained precursor was calcined at 800 °C for 5 h. Testing revealed obvious impurity peaks in the XRD pattern of the obtained product, indicating that the reaction was incomplete at this temperature and pure LaY phase was not formed. 1-X Cr X The O3 structure was observed. Simultaneously, the resulting powder was light in color and had a low overall chromaticity, indicating that lower calcination temperatures are not conducive to forming pigments with good chromaticity properties.

[0069] Comparative Example 3: Preparation of Inorganic Pigments by Changing Raw Materials

[0070] Except for the metal precursor, the preparation steps were the same as in Example 2. Lanthanum nitrate, yttrium nitrate, and chromium nitrate used in Example 2 were replaced with their corresponding carbonate precursors. During the experiment, it was found that due to the low solubility of carbonates in water, it was difficult to form a uniform metal ion solution, resulting in poor homogeneity of the reaction system. The product obtained after calcination at 1000℃ had larger particles and exhibited a certain degree of agglomeration; its overall color and near-infrared reflectance properties were lower than those of the sample obtained in the example. This indicates that using nitrates as the metal precursor is more beneficial for obtaining LaY with a uniform structure and excellent performance. 1- X Cr X O3 pigment.

[0071] Characterization performance testing:

[0072] (1) A Bruker D8 Advance A25 X-ray diffractometer was used. Diffraction data were acquired in a step scan mode within the range of 2θ = 20°–80°, with a step size of 0.02° and a counting time of 0.01 s per step. The results are as follows: Figure 1 As shown. Figure 1 The XRD patterns shown indicate that within the studied Cr doping range (x = 0–0.1), Examples 1-4 all maintain the main phase structure of Comparative Example 1, and no obvious impurity phase peaks were observed, indicating that Cr doping did not disrupt the formation of the LaYO3 perovskite structure.

[0073] (2) The test was conducted using a UV-Vis-NIR spectrophotometer (Shimadzu UV-3600) equipped with an integrating sphere, with barium sulfate (BaSO4) as a white reference. Reflectance spectra were acquired in the wavelength range of 300–2500 nm, with a scan step of 5 nm. Near-infrared solar reflectance (R*) was calculated according to ASTM standard G173-03, using the following formula:

[0074] R*

[0075] Where R(λ) is the reflectivity of the material at wavelength λ, and I(λ) is the solar spectral irradiance according to the ASTM G173-03 standard.

[0076] The results are as follows Figure 2 As shown, Figure 2 In Figure a, it is shown that in Examples 1-4 and Comparative Example 1, the visible light reflectance continuously decreased as the Cr content increased, resulting in a darker color in the samples. Figure 2 In Figure b, it is shown that although Cr 3+ Ions enhanced visible light absorption, but all doped samples still maintained high near-infrared reflectance (>70%). Figure 3 The results, obtained by multiplying the diffuse reflectance of Examples 1-4 and Comparative Example 1 by the normalized AM1.5 solar spectral irradiance wavelength by wavelength, indicate that the energy levels or defect states introduced by doping enhance light absorption in the near-infrared region, thereby weakening the material's effective reflectivity to solar near-infrared radiation.

[0077] The high near-infrared reflectance yellow inorganic pigment has a near-infrared reflectance of 67.561%-75.73% at 895nm and 78.166%-80.765% at 1350nm.

[0078] When x = 0.025, the chemical formula of the yellow inorganic pigment is LaY. 0.975 Cr 0.025O3 has a near-infrared reflectance of 71.498% at 895nm and 79.317% at 1350nm.

[0079] When x = 0.05, the chemical formula of the yellow inorganic pigment is LaY. 0.95 Cr 0.05 O3 has a near-infrared reflectance of 75.73% at 895nm and 80.765% at 1350nm.

[0080] When x = 0.075, the chemical formula of the yellow inorganic pigment is LaY. 0.925 Cr 0.075 O3 has a near-infrared reflectance of 68.919% at 895nm and 78.166% at 1350nm.

[0081] When x = 0.1, the chemical formula of the yellow inorganic pigment is LaY. 0.925 Cr 0.075 O3 has a near-infrared reflectance of 67.561% at 895nm and 78.434% at 1350nm.

[0082] The reflectance was measured using a Shimadzu UV-Vis-NIR spectrophotometer (Shimadzu UV-3600), with barium sulfate as a white reference. Reflectance spectra were acquired in the wavelength range of 300–2500 nm with a scan step of 5 nm. The average near-infrared reflectance of the pigment was calculated by summing and averaging the near-infrared reflectance in each band. Specific data are as follows:

[0083] The average near-infrared reflective pigment has an average near-infrared reflectance greater than 70%, for example, 73%-79%. For example, the average near-infrared reflectance is 76.4% when x = 0.025, 78.6% when x = 0.05, 73% when x = 0.075, and 74.1% when x = 0.1.

[0084] (3) The pigment chromaticity was measured using a CS-5960GX spectrophotometer. Color data were obtained based on the CIE 1976 L*a*b* color space recommended by the International Commission on Illumination (CIE), where L* represents color lightness (L* = 0 for black, L* = 100 for white), a* represents the green (-) to red (+) axis, and b* represents the blue (-) to yellow (+) axis. The chromaticity parameter C* represents color saturation, and its calculation formula is:

[0085] C*=

[0086] Table 2, L*a*b* data for Examples 1-4

[0087]

[0088] As the molar amount of Cr(III) doping increases, the pigment color changes from light yellow to deep yellow. The luminance L* value of the yellow inorganic pigment decreases from 88.17 to 77.58 with increasing dopant ion content, the a* value decreases from -1.56 to -2.02 and then increases from -2.02 to 0.04 with increasing dopant ion content, and the b* value increases from 23.31 to 39.76 with increasing dopant ion content, as shown in Table 2, exhibiting excellent color rendering performance and overall color purity.

[0089] (4) Figure 4 The band structure and associated orbital contributions of the systems in Examples 1-4 are schematically illustrated. This intermediate energy level formed by Cr3d–O 2p hybridization effectively modulates the electronic structure of the material, not only reducing the band gap but also significantly enhancing the light absorption capability of Examples 1-4 in the visible to near-infrared band.

[0090] (5) Figure 5 The images shown are actual pigment images of Examples 1-4 and Comparative Example 1, from left to right. They show that as the doping amount of Cr(III) increases, the color of the pigment powder changes from white to light yellow and then to dark yellow.

[0091] (6) The morphological characteristics of the pigment powder were observed using a field emission scanning electron microscope (FESEM, Hitachi S-4800). Figure 6 This demonstrates that Example 2 did not cause excessive grain growth, and while ensuring good crystallinity, it still maintained a certain degree of structural looseness.

[0092] (7) The elemental composition and distribution of the samples in Example 2 were analyzed using the equipped characteristic X-ray energy dispersive spectrometer (EDS, EX-250). Figure 7 The EDS energy dispersive spectroscopy and its quantitative results (weight percentage) showed that only La, Y, O and Cr elements were detected in the sample, and no other impurity element signals were found, indicating that the prepared sample has high chemical purity.

[0093] (8) The thermal stability of the pigment precursor was tested using a simultaneous thermal analyzer (NETZSCH, STA2500 & DSC214). Figure 8 Comparative Example 1 is shown. Figure 8 Example a) and Example 2 ( Figure 8 (b) TG curves of the precursor from room temperature to 1000°C. Both samples exhibit similar thermal decomposition behavior, indicating that Cr... 3+The introduction of Cr did not significantly change the decomposition pathway of the precursor, confirming that the incorporation of Cr has little effect on the thermal stability of the LaYO3 matrix.

[0094] (9) X-ray photoelectron spectroscopy (XPS) was used to measure the surface chemical composition and valence state information of Example 2. The experiment was performed on an Axis Supra X-ray photoelectron spectrometer, and all binding energies were corrected for the C 1s peak (284.8 eV). Figure 9 The high-resolution Cr 2p3 / 2 spectrum of Example 2 is shown. No characteristic peaks of hexavalent chromium were detected in the spectrum, indicating that chromium mainly exists as stable Cr. 3+ The valence state exists. This confirms that Cr... 3+ Successfully incorporated into the LaYO3 lattice, rather than forming a chromium oxide impurity phase.

[0095] Table 3. Color coordinates after acid and alkali resistance tests in Example 2

[0096]

[0097] The above embodiments of the present invention are merely preferred embodiments, used to illustrate the technical solutions of the present invention, and not to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, or improvements made to the technical solutions within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high near-infrared reflectance yellow inorganic pigment, characterized in that, The high near-infrared reflective yellow inorganic pigment has a chemical formula of LaY 1-X Cr X O3, wherein 0 < x ≤ 0.10, Cr(III) is a doping element, and x represents the doping molar amount of Cr(III).

2. The method for preparing the high near-infrared reflectance yellow inorganic pigment according to claim 1, characterized in that, The preparation method includes the following steps: S1. Using Cr, La, and Y sources as raw materials, according to the chemical formula LaY 1-X Cr X Weigh the raw materials according to the stoichiometric ratio of each element in O3; S2. Add the weighed powder raw materials from S1 to deionized water and stir in a magnetic stirrer until a clear solution is obtained. Then add citric acid, glucose, and acrylamide in sequence. S3. Set the temperature of the magnetic stirrer, stir for a period of time, and put the resulting gel into an oven to dry for a period of time to obtain the precursor; S4. Place the dried precursor from S3 into a mortar and grind it, then pour the ground powder into a crucible. S5. Place the crucible from S4 into a muffle furnace and sinter it at high temperature in the muffle furnace to obtain a yellow inorganic pigment with high near-infrared reflectance and a single yellow phase.

3. The preparation method according to claim 2, characterized in that, In S1, the La source is provided by at least one of La-containing carbonates, oxides, chlorides, and nitrates; The Y source is provided by at least one of carbonates, oxides, chlorides and nitrates containing Y. The Cr source is provided by at least one of Cr-containing carbonates, oxides, chlorides, and nitrates.

4. The preparation method according to claim 2, characterized in that, In S2, add deionized water, citric acid, glucose, and acrylamide, and stir for 10-30 minutes. The magnetic stirrer speed is 700-900 r / min.

5. The preparation method according to claim 2, characterized in that, In S3, the magnetic stirrer temperature is set to 60℃-80℃, the stirring time is 4-5h, and the magnetic stirrer speed is 700-900 r / min.

6. The preparation method according to claim 2, characterized in that, In S3, the drying time in the oven is 10-14 hours, and the oven temperature is 100℃-120℃.

7. The preparation method according to claim 2, characterized in that, In S4, the grinding time is 15-30 minutes.

8. The preparation method according to claim 2, characterized in that, In S5, the muffle furnace condition is set as follows: The heating rate is 5-10℃ / min, raising the temperature from room temperature to 800℃-1000℃, holding for 5-6 hours in an air atmosphere; then cooling is carried out at a cooling rate of 5-10℃ / min.

9. The application of the high near-infrared reflectance yellow inorganic pigment according to claim 1, characterized in that, Used in energy-saving materials for building exteriors, coatings, plastics, and vehicle or ship decks.

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