A cerium oxide doped material and its preparation method and application

Abstract

The present invention provides a cerium oxide doped material, a preparation method thereof and an application thereof. The cerium oxide doped material includes a cerium oxide matrix and a dopant doped in the cerium oxide matrix; the dopant includes an alkali metal oxide and at least two rare earth oxides other than cerium; and the following formulas 1 and 2 are also satisfied: 0.2 < M < 0.4, formula 1, 1 < N < 2, formula 2, where M is the emissivity of the cerium oxide doped material at 600 °C, and N is the thermal conductivity of the cerium oxide doped material at 600 °C. The cerium oxide doped material provided by the present invention has a low infrared radiation degree in a high temperature environment of 600 °C and is suitable for high temperature resistant low infrared emission scenarios.

Description

Technical Field

[0001] The invention belongs to the field of low infrared emission materials and relates to a cerium oxide doped material and a preparation method and application thereof. Background Art

[0002] In low infrared emission scenarios, it is necessary to reduce or change the infrared radiation characteristics of the target part, so that it is difficult for infrared detection equipment to detect or the probability of being detected is reduced. At present, applying a low infrared emissivity coating on the surface of the target part is still the most important way to reduce infrared radiation. However, with the development of technology, the temperature of the hot end of some target parts has reached 600℃, and the increase in temperature leads to an increase in the infrared radiation of the hot end, which is easy to be detected by infrared detectors. According to Stefan Boltzmann's law: E=εδT 4 , ε is the surface emissivity of the material, δ is the Stefan-Boltzmann constant, and T is the surface temperature. Infrared emissivity is proportional to the fourth power of emissivity and temperature. Therefore, the key to achieving low infrared emissivity is to ensure that the coating material has both high-temperature, low infrared emissivity, and low thermal conductivity.

[0003] Traditional low-infrared radiation materials primarily include metal powders, photonic crystals, and inorganic low-emissivity materials. Metal powders such as Au, Ag, and Al achieve excellent low infrared emissivity primarily due to their excellent electrical conductivity. However, metal powders are susceptible to oxidation in high-temperature environments, significantly increasing their infrared emissivity. Photonic crystals are a new class of synthetic low-infrared emissivity materials. Although they offer extremely low infrared emissivity, they can only be used below 300°C and cannot withstand high-temperature environments. Furthermore, their preparation equipment is expensive and the process is complex, far from meeting practical requirements. Inorganic low-emissivity materials primarily include metal oxides, of which cerium oxide is the most widely used. However, its high infrared emissivity (approximately 0.5) at high temperatures makes it unsuitable for high-temperature use. To achieve low infrared emissivity at high temperatures, doping cerium oxide is currently the mainstream approach. However, while existing cerium oxide doping systems achieve high-temperature low infrared emissivity, their thermal conductivity is often unsatisfactory. Summary of the Invention

[0004] The present invention provides a cerium oxide doped material, which has both low infrared emissivity and low thermal conductivity under a temperature environment of 600°C.

[0005] The present invention also provides a method for preparing a cerium oxide doped material, which can successfully prepare the above-mentioned cerium oxide doped material.

[0006] The present invention also provides a low-infrared-emission ceramic. Since the preparation raw materials of the ceramic include the above-mentioned cerium oxide doping material, it has a low infrared emissivity in a temperature environment of 600 °C.

[0007] In a first aspect, the present invention provides a cerium oxide doping material, the cerium oxide doping material includes a cerium oxide matrix and a dopant doped in the cerium oxide matrix; the dopant includes an alkali metal oxide and at least two non-cerium rare earth oxides;

[0008] It also satisfies the following formula 1 and formula 2:

[0009] 0.2 < M < 0.4, formula 1,

[0010] 1 < N < 2, formula 2,

[0011] wherein, M is the emissivity of the cerium oxide doping material at 600 °C, and N is the thermal conductivity of the cerium oxide doping material at 600 °C.

[0012] In a preferred embodiment, the alkali metal oxide is selected from Na2O and / or K2O.

[0013] In a preferred embodiment, the rare earth oxides are selected from at least two of La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Dy2O3, Er2O3, Yb2O3, Lu2O3, Y2O3, Sc2O3.

[0014] In a preferred embodiment, the doping molar ratio of the dopant is 10% - 20%.

[0015] In a preferred embodiment, in the alkali metal oxide and the rare earth oxide, the molar ratio of the alkali metal element to the rare earth element is 1 - 1.5:1 - 4.5.

[0016] In a preferred embodiment, in any two non-cerium rare earth oxides, the molar ratio of the rare earth elements is 1 - 1.5:1 - 1.5.

[0017] In a preferred embodiment, the particle size of the cerium oxide doping material is 100 - 1500 nm.

[0018] In a preferred embodiment, the cerium oxide doping material is prepared by a method including the following process: adding a precipitating agent to a raw material mixing system containing a cerium salt and a non-cerium rare earth salt, carrying out a precipitation reaction under the conditions of a pH value of 7 - 8.5 and a temperature of 30 - 50 °C, standing and aging for 1 - 5 hours to obtain a precipitation precursor; mixing the precipitation precursor with an alkali metal salt, drying, and calcining at 900 - 1000 °C for 2 - 3 hours to obtain the cerium oxide doping material.

[0019] In a second aspect, the present invention provides a method for preparing the above cerium oxide doped material, comprising the following steps:

[0020] A precipitating agent is added to a raw material mixing system containing a cerium salt and a non-cerium rare earth salt. After a precipitation reaction occurs under the conditions of a pH value of 7 - 8.5 and a temperature of 30 - 50 °C, it is left to stand and age for 1 - 5 hours to obtain a precipitate precursor; the precipitate precursor is mixed with an alkali metal salt, dried, and calcined at 900 - 1000 °C for 2 - 3 hours to obtain the cerium oxide doped material.

[0021] In a third aspect, the present invention provides a low infrared emission ceramic, the raw material for preparing which is the above cerium oxide doped material.

[0022] The cerium oxide doped material provided by the present invention has both a low infrared emissivity and a low thermal conductivity in a temperature environment of 600 °C, and is suitable for high-temperature resistant low infrared emission scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 XRD diagrams of the cerium oxide doped materials of Examples 1 - 4 and standard cerium oxide;

[0024] Figure 2 SEM diagram of the cerium oxide doped material of Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] In one aspect, the present invention provides a cerium oxide doped material, which includes a cerium oxide matrix and a dopant doped in the cerium oxide matrix; the dopant includes an alkali metal oxide and at least two non-cerium rare earth oxides;

[0027] It also satisfies the following Formulas 1 and 2:

[0028] 0.2 < M < 0.4 Formula 1,

[0029] 1 < N < 2 Formula 2,

[0030] where M is the emissivity of the cerium oxide doped material at 600 °C (ambient temperature), and N is the thermal conductivity of the cerium oxide doped material at 600 °C (ambient temperature), unit: W·m -1 ·K -1 .

[0031] The infrared emissivity of cerium oxide is as high as about 0.5 at 600°C (ambient temperature), which cannot meet the use requirements of low infrared emission scenarios. The cerium oxide doped material of the present invention has significantly low infrared emissivity at high temperatures. The reason is that the change in charge in the lattice has a certain degree of influence on the temperature characteristics, infrared radiation characteristics, etc. of the material. The present invention generates oxygen vacancies by low-valent doping cerium oxide, increases the number of free electrons in the material system, improves the electrical conductivity of the material system, and thereby increases the infrared reflectivity and reduces the infrared emissivity. Moreover, due to the charge change of the above-mentioned doped material, when the ambient temperature rises, the phonon scattering of the material system is enhanced, thereby significantly reducing the thermal conductivity of the material, its surface temperature and infrared emissivity, and reducing the probability of detection at high temperatures.

[0032] Furthermore, the alkali metal oxide is selected from Na2O and / or K2O.

[0033] Among them, the valence of the metals in the alkali metal oxides and rare earth oxides of the present invention is lower than the valence of cerium in cerium oxide. With the addition of low-valence dopants, the charge balance in the cerium oxide lattice changes, more oxygen vacancies are generated, and the number of free electrons in the material system increases, thereby improving the electrical conductivity of the material system; and due to the doping of alkali metals and at least two other rare earth oxides, stronger phonon scattering can also be brought about, thereby achieving low infrared radiation of the cerium oxide doped material in a high-temperature environment.

[0034] Furthermore, the rare earth oxides are selected from at least two of the group consisting of La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Dy2O3, Er2O3, Yb2O3, Lu2O3, Y2O3, and Sc2O3. The rare earth metal valence of these rare earth oxides is lower than that of cerium in cerium oxide. However, this difference, within a certain range, can alter the charge balance within the cerium oxide-doped material's lattice to a certain extent. The inventors have discovered that these rare earth oxides can create more oxygen vacancies within the cerium oxide lattice, significantly increasing the number of free electrons in the material system. This significantly reduces the infrared emissivity of the cerium oxide-doped material at high temperatures.

[0035] Furthermore, the doping molar ratio of the dopant is 10%-20%.

[0036] It can be understood that the doping molar ratio of the dopant refers to the molar ratio of the dopant to the cerium oxide doping material.

[0037] Through research, the inventors discovered that the ability to form oxygen vacancies without causing crystal structure collapse after doping is due to the lattice's ability to withstand a certain degree of lattice distortion. However, different crystals have certain limits on the lattice distortion they can tolerate, and therefore the doping ratio of the dopant should ideally be limited. Through research, the inventors discovered that a molar doping ratio within the range of the present invention can maintain an appropriate degree of cerium oxide lattice distortion, effectively preventing crystal structure collapse and improving the infrared emissivity and thermal conductivity of the cerium oxide-doped material at high temperatures.

[0038] Furthermore, the molar ratio of the alkali metal to the rare earth element in the alkali metal oxide and the rare earth oxide is 1-1.5:1-4.5. Different alkali metal oxides and rare earth oxides have different mesocrystalline structures and metal valence states, so their doping ratios have different effects on the cerium oxide lattice. The inventors have discovered that when the doping molar ratio of the alkali metal oxide to the rare earth oxide falls within the range of the present invention, the charge change of the cerium oxide can be better controlled, thereby generating more oxygen vacancies and enhancing phonon scattering.

[0039] Furthermore, in any two non-cerium rare earth oxides, the molar ratio of the rare earth elements is 1-1.5:1-1.5.

[0040] The inventors have found that when the dopant includes at least two rare earth oxides, the phonon scattering of the doped material can be better enhanced.

[0041] Furthermore, the particle size of the cerium oxide doping material is 100-1500 nm. It can be understood that the particle size of the cerium oxide doping material is not unique, with a maximum of 1200 nm and a minimum of 100 nm. The inventors have found that the particle size of the cerium oxide doping material has a certain impact on reducing infrared emissivity. Cerium oxide doping materials within the scope of the present invention can achieve high temperature and low infrared emissivity.

[0042] In a specific embodiment of the present invention, SEM observation shows that the cerium oxide doped material is dense and uniform, and the average grain size thereof is 100-1500 nm.

[0043] In addition, the particle size involved in the present invention refers to the "primary particles" of the material, that is, the primary structure of a single particle, and "secondary particles" refer to aggregates of primary particles through physical or chemical bonding between primary particles, that is, secondary structures.

[0044] In principle, the present invention does not impose any specific limitations on the preparation method of the cerium oxide doping material. For example, conventional doping methods such as coprecipitation, solid-phase method, sol-gel method, and hydrothermal method can all successfully incorporate the doping material into the cerium oxide matrix. However, to better reduce the high-temperature infrared emissivity and thermal conductivity of the doping material, coprecipitation is preferred. The cerium oxide doping material obtained by coprecipitation has a smaller and more uniform particle size.

[0045] In a preferred embodiment of the present invention, the cerium oxide doping material is prepared by a method comprising the following processes: adding a precipitant to a raw material mixture system containing a cerium salt and a non-cerium rare earth salt, causing a precipitation reaction under conditions of a pH value of 7-8.5 and a temperature of 30-50°C, and then standing and aging for 1-5 hours to obtain a precipitated precursor; mixing the precipitated precursor with an alkali metal salt, drying, and calcining at 900-1000°C for 2-3 hours to obtain the cerium oxide doping material.

[0046] In another aspect, the present invention provides a method for preparing the cerium oxide doped material, comprising the following steps:

[0047] A precipitant is added to a raw material mixture system containing a cerium salt and a non-cerium rare earth salt, and a precipitation reaction occurs under conditions of a pH value of 7-8.5 and a temperature of 30-50°C. The mixture is then allowed to stand and aged for 1-5 hours to obtain a precipitation precursor; the precipitation precursor is mixed with an alkali metal salt, dried, and calcined at 900-1000°C for 2-3 hours to obtain the cerium oxide doping material.

[0048] The above preparation method can successfully prepare cerium oxide doped materials with a particle size of 100-1500 nm by regulating the parameters of the steps such as reaction temperature and aging time. Therefore, the preparation method provided by the present invention can further reduce the infrared radiation of the cerium oxide doped material.

[0049] As for the type of precipitant, the present invention does not make any specific limitation. Technicians can choose conventional precipitants such as oxalic acid and amine salts. In order to control the reaction rate, the present invention preferably uses oxalic acid, and more preferably a 0.5M oxalic acid solution.

[0050] In the above preparation method, the anions in the cerium salt and rare earth salt are not specifically limited in the present invention, and technicians can choose corresponding sulfates, nitrates or chlorides, etc.; as for the alkali metal salt, it includes but is not limited to alkali metal carbonates, alkali metal basic carbonates, alkali metal sulfates, alkali metal nitrates, alkali metal acetates, etc.

[0051] In the above preparation method, the pH value is within the range of 7-8.5, which can be achieved by adjusting the pH of an alkaline solution, such as using aqueous ammonia. The present invention does not specifically limit whether it is achieved by adjusting the pH of the raw material mixture system, adjusting the pH of the precipitant, or adjusting the pH after adding the precipitant.

[0052] In another aspect, the present invention provides a low infrared emission ceramic, the raw materials for preparing the ceramic include the above-mentioned cerium oxide doping material.

[0053] It is understood that the cerium oxide doped material of the present invention is not limited to the preparation of ceramics, but can also be low infrared emission paints, coatings, equipment, etc., and ceramics is just one possibility exemplified by the present invention.

[0054] The cerium oxide doping material provided by the present invention will be further described below with reference to specific examples. In the following examples, unless otherwise specified, all raw materials can be purchased commercially or prepared by conventional methods.

[0055] Example 1

[0056] This embodiment provides a cerium oxide doping material, wherein the dopant composition of the material is: Eu2O3, Gd2O3, and Na2O; and the doping amount is 20 wt mol%.

[0057] The cerium oxide doped material is prepared according to the following method:

[0058] The co-precipitation method was chosen for preparation. Three rare earth nitrates, Eu(NO3)3·6H2O, Gd(NO3)3·6H2O, and Ce(NO3)3·6H2O, were mixed and then added to deionized water to prepare a uniform mixed solution (0.1M). A certain amount of oxalic acid was weighed and added to deionized water to prepare a uniform solution (0.5M). The pH was then adjusted to 8 with ammonia. The mixed solution of rare earth nitrates was added dropwise to an oxalic acid-ammonia solution stirred at 40°C. After reacting for 2 hours, it was allowed to stand for 1 hour, centrifuged, and washed with deionized water and ethanol three times each to obtain a hydroxide precipitation precursor. Na2CO3·10H2O was added to the precipitation precursor to ensure that the dopants were mixed in an equimolar ratio (n (Eu) :n (Gd) :n (Na) =1:1:1), dried at 70°C for 10 hours, sieved with a 200-mesh sieve, and calcined at 900°C for 2 hours to remove residual moisture and anhydrous ethanol to obtain cerium oxide doped material powder, the microstructure of which is shown in FIG. Figure 2 As shown by Figure 2 It can be seen that the cerium oxide doped material prepared in this example is dense and has good uniformity, and its average grain size is 0.5-1 μm.

[0059] This example also provides a low infrared emission ceramic, the preparation process of which is as follows:

[0060] (1) Green billet molding: The cerium oxide doped material powder prepared above is placed in a mold and pressed by double-sided pressing at a molding pressure of 5 MPa. The pressed green billet is of ceramic size. Subsequently, it is molded by cold isostatic pressing at a pressure of 250 MPa to obtain a dense green billet.

[0061] (2) Ceramic sintering: The dense green blank is sintered in a silicon-molybdenum rod furnace. To avoid volatilization, a buried firing method is adopted. The sintering temperature is controlled at 1550°C and the holding time is 3 hours. After sintering, a dense ceramic is obtained;

[0062] (3) Post-processing of ceramics: Use 2000-grit sandpaper to polish the sintered ceramics to eliminate the influence of surface roughness on the determination of infrared emissivity.

[0063] Example 2

[0064] This embodiment provides a cerium oxide doping material, wherein the dopant composition of the material is La2O3, Nd2O3, Sm2O, and Na2O, and the doping amount is 20 mol%.

[0065] The cerium oxide doped material is prepared as follows:

[0066] The coprecipitation method was chosen for preparation. Rare earth nitrates of various types, including La(NO3)3·6H2O, Nd(NO3)3·6H2O, Sm(NO3)3·6H2O, and Ce(NO3)3·6H2O, were mixed and then added to deionized water to form a uniform solution (0.1M). A certain amount of oxalic acid was weighed and added to deionized water to form a uniform solution (0.5M). The pH was then adjusted to 8 with ammonia. The rare earth nitrate solution was added dropwise to an oxalic acid-ammonia solution stirred at 40°C. After the reaction was complete, the mixture was allowed to stand for 1 hour, centrifuged, and washed three times with deionized water and ethanol to obtain a precipitated precursor. Na2CO3·10H2O was added to the precipitated precursor to ensure that the dopants were mixed in equimolar ratios (n (La) :n (Nd) :n (Sm) :n (Na) =1:1:1:1), dried at 70° C. for 10 hours, sieved with a 200-mesh sieve, and calcined at 900° C. for 2 hours to remove residual moisture and anhydrous ethanol to obtain a cerium oxide doped material powder.

[0067] This example also provides a low infrared emission ceramic, the preparation process of which is as follows:

[0068] (1) Green billet molding: The cerium oxide doped material powder prepared above is placed in a mold and pressed by double-sided pressing at a molding pressure of 5 MPa. The pressed green billet is of ceramic size. Subsequently, it is molded by cold isostatic pressing at a pressure of 250 MPa to obtain a dense green billet.

[0069] (2) Ceramic sintering: The dense green blank is sintered in a silicon-molybdenum rod furnace. To avoid volatilization, a buried firing method is adopted. The sintering temperature is controlled at 1550°C and the holding time is 3 hours. After sintering, a dense ceramic is obtained;

[0070] (3) Post-processing of ceramics: Use 2000-grit sandpaper to polish the sintered ceramics to eliminate the influence of surface roughness on the determination of infrared emissivity.

[0071] Example 3

[0072] This embodiment provides a cerium oxide doping material, wherein the dopant composition of the material is: Eu2O3, Gd2O3, Dy2O3, Er2O3, Na2O, and the doping amount is 20 mol%.

[0073] The cerium oxide doped material is prepared according to the following method:

[0074] The coprecipitation method was chosen for preparation. Various rare earth nitrates, including Eu(NO3)3·6H2O, Gd(NO3)3·6H2O, Dy(NO3)3·6H2O, and Er(NO3)3·6H2O, were mixed and then added to deionized water to form a uniform solution (0.1M). A certain amount of oxalic acid was weighed and added to deionized water to form a uniform solution (0.5M). The pH was then adjusted to 8 with ammonia. The rare earth nitrate solution was added dropwise to an oxalic acid-ammonia solution stirred at 40°C. After the reaction was complete, the mixture was allowed to stand for 1 hour, centrifuged, and washed three times with deionized water and ethanol to obtain a precipitate precursor. Na2CO3·10H2O was added to the precipitate precursor to ensure that the dopants were mixed in equimolar ratios (n (Eu) :n (Gd) :n (Dy) :n (Er) :n (Na) =1:1:1:1:1), the doping amount of which is 20 mol%, and the mixture is dried at 70°C for 10 hours, sieved with a 200-mesh sieve, and the sieved powder is calcined at 900°C for 2 hours to remove residual moisture and anhydrous ethanol to obtain a cerium oxide doped material powder.

[0075] This example also provides a low infrared emission ceramic, the preparation process of which is as follows:

[0076] (1) Green billet molding: The cerium oxide doped material powder prepared above is placed in a mold and pressed by double-sided pressing at a molding pressure of 5 MPa. The pressed green billet is of ceramic size. Subsequently, it is molded by cold isostatic pressing at a pressure of 250 MPa to obtain a dense green billet.

[0077] (2) Ceramic sintering: The dense green blank is sintered in a silicon-molybdenum rod furnace. To avoid volatilization, a buried firing method is adopted. The sintering temperature is controlled at 1550°C and the holding time is 3 hours. After sintering, a dense ceramic is obtained;

[0078] (3) Post-processing of ceramics: Use 2000-grit sandpaper to polish the sintered ceramics to eliminate the influence of surface roughness on the determination of infrared emissivity.

[0079] Example 4

[0080] This embodiment provides a cerium oxide doping material, wherein the dopant composition of the material is: Yb2O3, Lu2O3, Y2O3, Sc2O3, K2O, and the doping amount is 10 mol%.

[0081] The cerium oxide doped material is prepared according to the following method:

[0082] The coprecipitation method was chosen for preparation. Yb(NO3)3·6H2O, Lu(NO3)3·6H2O, Y(NO3)3·6H2O, and Sc(NO3)3·6H2O were mixed and added to deionized water to form a uniform solution (0.1M). A certain amount of oxalic acid was weighed and added to deionized water to form a uniform solution (0.5M). The pH was then adjusted to 8 with ammonia. The rare earth nitrate solution was added dropwise to an oxalic acid-ammonia solution stirred at 40°C. After the reaction was complete, the mixture was allowed to stand for 1 hour, centrifuged, and washed three times with deionized water and ethanol to obtain a precipitated precursor. K2CO3·10H2O was added to the precipitated precursor to ensure that the dopants were mixed in equimolar ratios (n (Yb) :n (Lu) :n (Y) :n (Sc) :n (K) =1:1:1:1:1), wherein the doping amount is 10 mol%, dried at 70 ° C for 10 hours, sieved with a 200 mesh sieve, and calcined at 900 ° C for 2 hours to remove residual moisture and anhydrous ethanol to obtain a cerium oxide doped material powder.

[0083] This example also provides a low infrared emission ceramic, the preparation process of which is as follows:

[0084] (1) Green billet molding: The cerium oxide doped material powder prepared above is placed in a mold and pressed by double-sided pressing at a molding pressure of 5 MPa. The pressed green billet is of ceramic size. Subsequently, it is molded by cold isostatic pressing at a pressure of 250 MPa to obtain a dense green billet.

[0085] (2) Ceramic sintering: The dense green blank is sintered in a silicon-molybdenum rod furnace. To avoid volatilization, a buried firing method is adopted. The sintering temperature is controlled at 1550°C and the holding time is 3 hours. After sintering, a dense ceramic is obtained;

[0086] (3) Post-processing of ceramics: Use 2000-grit sandpaper to polish the sintered ceramics to eliminate the influence of surface roughness on the determination of infrared emissivity.

[0087] Performance Testing

[0088] (1) The cerium oxide doped materials of Examples 1-4 were taken as samples to be tested, denoted as A to D, and subjected to X-ray diffraction analysis. The results are shown in FIG. Figure 1 .

[0089] (2) Under a 600°C environment, the emissivity (referring to the GJB-2502 standard) and thermal conductivity of the low infrared emission ceramics of Examples 1-4 were tested, and E = εδT was used to calculate the thermal conductivity. 4 The infrared radiation of the sample was calculated using the formula, and the results are shown in Table 1.

[0090] In this test, the formula for calculating the high-temperature thermal conductivity of the sample is: λ=α(T)×Cp(T)×ρ(T),

[0091] Where λ, α(T), Cp(T), and ρ(T) are thermal conductivity, thermal diffusivity, specific heat capacity, and sample density, respectively. Thermal diffusivity was obtained using laser thermal conductivity. Sample density was determined using the Archimedean displacement method, and specific heat capacity was calculated using the Neumann-Kopp rule.

[0092] Table 1: Radiometric values ​​of different samples

[0093]

[0094] Results and analysis: Figure 1 It can be seen that compared with the standard PDF card of single-phase cerium oxide, the cerium oxide doped materials prepared in Examples 1-4 all have fluorite structures, and each spectrum has no impurity peaks, indicating that the cerium salt and rare earth salt in the raw materials form a uniform solid solution.

[0095] Combined with Table 1, it can be seen that the infrared emissivity of the doped cerium oxide material prepared by the present invention is less than 0.4 at a temperature of 600°C, and the thermal conductivity is less than 2W·m -1 ·K -1, the radiation is less than 2300W, which is suitable for high temperature resistant low infrared emission scenes.

[0096] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cerium oxide doped material, characterized in that The cerium oxide doped material includes a cerium oxide matrix and a dopant doped in the cerium oxide matrix; the dopant includes an alkali metal oxide and at least two non-cerium rare earth oxides; It also satisfies the following formula 1 and formula 2: 0.2 < M < 0.4 Formula 1, 1 < N < 2 Formula 2, where M is the emissivity of the cerium oxide doped material at 600 °C, and N is the thermal conductivity of the cerium oxide doped material at 600 °C; The alkali metal oxide is selected from Na2O and / or K2O; The rare earth oxides are selected from at least two of La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Dy2O3, Er2O3, Yb2O3, Lu2O3, Y2O3, Sc2O3; in the alkali metal oxide and the rare earth oxide, the molar ratio of the alkali metal element to the rare earth element is 1 - 1.5:1 - 4.5; The particle size of the cerium oxide doped material is 100 - 1500 nm; wherein, the particle size refers to the primary particle of the material.

2. The cerium oxide doped material according to claim 1, characterized in that The doping molar ratio of the dopant is 10% - 20%.

3. The cerium oxide doped material according to any one of claims 1-2, characterized in that Among any two non-cerium rare earth oxides, the molar ratio of the rare earth elements is 1 - 1.5:1 - 1.

5.

4. The cerium oxide doped material according to any one of claims 1 to 3, characterized in that The cerium oxide doped material is prepared by a method including the following process: Adding a precipitating agent to a raw material mixing system containing a cerium salt and a non-cerium rare earth salt, carrying out a precipitation reaction under the conditions of a pH value of 7 - 8.5 and a temperature of 30 - 50 °C, standing and aging for 1 - 5 hours to obtain a precipitate precursor; mixing the precipitate precursor with an alkali metal salt, drying, and calcining at 900 - 1000 °C for 2 - 3 hours to obtain the cerium oxide doped material.

5. A method for preparing a cerium oxide doped material according to any one of claims 1 to 4, characterized in that: It includes the following steps: Adding a precipitating agent to a raw material mixing system containing a cerium salt and a non-cerium rare earth salt, carrying out a precipitation reaction under the conditions of a pH value of 7 - 8.5 and a temperature of 30 - 50 °C, standing and aging for 1 - 5 hours to obtain a precipitate precursor; mixing the precipitate precursor with an alkali metal salt, drying, and calcining at 900 - 1000 °C for 2 - 3 hours to obtain the cerium oxide doped material.

6. A low infrared emission ceramic, characterized in that: Its preparation raw materials include the cerium oxide doped material according to any one of claims 1 - 4.

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