Rare earth orthophosphate ceramic powder as well as preparation method and application thereof

Abstract

The invention provides rare earth orthophosphate ceramic powder as well as a preparation method and application thereof, and belongs to the technical field of ceramic materials. The preparation method of the rare earth orthophosphate ceramic powder provided by the invention comprises the following steps: mixing a rare earth salt solution, a barium salt / strontium salt solution, a phosphorus source solution, a complexing agent and an inorganic solvent, and carrying out complex reaction to obtain sol; the sol is dried, and dried gel is obtained; and calcining the xerogel to obtain the rare earth orthophosphate ceramic powder. The precursor (rare earth salt solution, barium salt / strontium salt solution and phosphorus source solution) in a solution form can be uniformly dispersed on a molecular level, so that the ceramic powder is uniform in size; a sol-gel method is adopted, and the particle size is always kept at the nanoscale in the sol-gel process, so that the ceramic powder with small particle size and uniform distribution is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic materials, and in particular relates to a rare earth orthophosphate ceramic powder and a preparation method and application thereof. Background Art

[0002] Thermal protection coatings have important and extensive application value in aerospace, large ships, large thermal power generation, etc. As the operating temperature of engines continues to increase, the development of new thermal protection coating materials has become a key issue in the research and development of high-performance aircraft engines.

[0003] Rare earth orthophosphate REM3P3O 12 (RE: rare earth element, M: Ba or Sr) has the advantages of excellent high temperature stability and extremely low thermal conductivity. In particular, this system material has a high thermal expansion coefficient, can achieve good thermal matching with nickel-based alloys, can greatly alleviate the stress caused by the mismatch between the thermal expansion coefficients of the matrix material and the ceramic layer, and is considered to be a potential candidate material for thermal protection coatings. However, the rare earth orthophosphate powder is currently mainly synthesized by solid phase reaction method, which has the disadvantage that the reaction activity of each raw material is low during the synthesis process, the migration speed is slow, and the raw materials cannot be evenly mixed at the atomic level. The synthesized REM3P3O 12 The particles of the powder are relatively large, resulting in low density of the prepared ceramics. Therefore, how to prepare rare earth orthophosphate with small particle size has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0004] The purpose of the present invention is to provide a rare earth orthophosphate ceramic powder and a preparation method and application thereof. The rare earth orthophosphate ceramic powder prepared by the preparation method provided by the present invention has a small particle size and is evenly distributed.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing rare earth orthophosphate ceramic powder, comprising the following steps:

[0007] (1) mixing a rare earth salt solution, a barium salt / strontium salt solution, a phosphorus source solution, a complexing agent and an inorganic solvent to carry out a complexing reaction to obtain a sol;

[0008] (2) drying the sol obtained in step (1) to obtain a xerogel;

[0009] (3) calcining the dry gel obtained in step (2) to obtain rare earth orthophosphate ceramic powder.

[0010] Preferably, the rare earth salt in step (1) comprises rare earth chloride or rare earth nitrate.

[0011] Preferably, the barium salt in step (1) includes barium chloride, barium nitrate or barium acetate; and the strontium salt includes strontium chloride, strontium nitrate or strontium acetate.

[0012] Preferably, the phosphorus source in step (1) comprises (NH4)2HPO4 or NH4H2PO4.

[0013] Preferably, the complexing agent in step (1) is citric acid.

[0014] Preferably, in step (1), the molar ratio of the rare earth salt, the barium salt / strontium salt, the phosphorus source and the complexing agent is 1:3:3:(3.5-8).

[0015] Preferably, the temperature of the complexation reaction in step (1) is 80-90° C., and the time of the complexation reaction is 2-8 hours.

[0016] Preferably, the drying in step (2) comprises first-stage drying and second-stage drying performed sequentially.

[0017] The present invention also provides rare earth orthophosphate ceramic powder prepared by the preparation method described in the above technical solution.

[0018] The present invention also provides the use of the rare earth orthophosphate ceramic powder described in the above technical solution in a thermal protective coating.

[0019] The present invention provides a method for preparing rare earth orthophosphate ceramic powder, comprising the following steps: mixing a rare earth salt solution, a barium salt / strontium salt solution, a phosphorus source solution, a complexing agent and an inorganic solvent, performing a complexing reaction, and obtaining a sol; drying the sol to obtain a dry gel; and calcining the dry gel to obtain a rare earth orthophosphate ceramic powder. The present invention first uses a precursor in the form of a solution (rare earth salt solution, barium salt / strontium salt solution, phosphorus source solution) that can be evenly dispersed at the molecular level, so that the ceramic powder has a uniform size; using a sol-gel method, the particle size is always maintained at the nanoscale during the sol-gel process, thereby obtaining a ceramic powder with a small particle size and uniform distribution. Experimental results show that the average grain size of the rare earth orthophosphate ceramic powder prepared by the preparation method provided by the present invention is 13.062 to 20.357 μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 XRD diagram of the rare earth orthophosphate ceramic powder prepared in Examples 1 to 7;

[0021] Figure 2 This is a particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 1;

[0022] Figure 3 The particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 2

[0023] Figure 4 This is a particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 3;

[0024] Figure 5 This is a particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 4;

[0025] Figure 6 This is a particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 5;

[0026] Figure 7 This is a particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 6;

[0027] Figure 8 This is a particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 7;

[0028] Fig. 9 It is the XRD diagram of the rare earth orthophosphate ceramic powder prepared in Comparative Examples 1 to 4. DETAILED DESCRIPTION

[0029] The present invention provides a method for preparing rare earth orthophosphate ceramic powder, comprising the following steps:

[0030] (1) mixing a rare earth salt solution, a barium salt / strontium salt solution, a phosphorus source solution, a complexing agent and an inorganic solvent to carry out a complexing reaction to obtain a sol;

[0031] (2) drying the sol obtained in step (1) to obtain a xerogel;

[0032] (3) calcining the dry gel obtained in step (2) to obtain rare earth orthophosphate ceramic powder.

[0033] The present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0034] The invention mixes rare earth salt solution, barium salt / strontium salt solution, phosphorus source solution, complexing agent and inorganic solvent, and performs complexing reaction to obtain sol.

[0035] In the present invention, the rare earth salt preferably includes rare earth chloride or rare earth nitrate; the solvent of the rare earth salt solution is preferably deionized water. The present invention has no special restrictions on the type of the rare earth, and rare earths well known to those skilled in the art can be used. The present invention has no special restrictions on the concentration of the rare earth salt solution, as long as it is prepared into a uniform solution.

[0036] In one embodiment of the present invention, the rare earth is yttrium, neodymium, samarium, gadolinium, holmium, erbium or thulium.

[0037] In the present invention, the barium salt preferably includes barium chloride, barium nitrate or barium acetate; the strontium salt preferably includes strontium chloride, strontium nitrate or strontium acetate; the solvent of the barium salt / strontium salt solution is preferably deionized water. The present invention has no particular limitation on the concentration of the barium salt / strontium salt solution, as long as it is prepared into a uniform solution.

[0038] In the present invention, the phosphorus source preferably includes (NH4)2HPO4 or NH4H2PO4; the solvent of the phosphorus source solution is preferably deionized water. The present invention has no particular limitation on the concentration of the phosphorus source solution, as long as it is prepared into a uniform solution.

[0039] In the present invention, the complexing agent is preferably citric acid. The present invention uses citric acid as the complexing agent, and the particle size of the ceramic powder can be further reduced by using the citric acid sol-gel method.

[0040] In the present invention, the inorganic solvent is preferably water, more preferably deionized water. The present invention has no particular limitation on the amount of the inorganic solvent, as long as the raw materials are dissolved.

[0041] In the present invention, the molar ratio of the rare earth salt, the barium salt / strontium salt, the phosphorus source and the complexing agent is preferably 1:3:3:(3.5-8), more preferably 1:3:3:4, 1:3:3:6 or 1:3:3:8. The present invention limits the molar ratio of the rare earth salt, the barium salt / strontium salt, the phosphorus source and the complexing agent to the above range to improve the degree of the complexing reaction.

[0042] In the present invention, the rare earth salt solution, the barium salt / strontium salt solution, the phosphorus source solution, the complexing agent and the inorganic solvent are preferably mixed in the following steps:

[0043] 1) mixing a complexing agent with an inorganic solvent to obtain a complexing agent solution;

[0044] 2) Adding the rare earth salt solution, the barium salt / strontium salt solution and the phosphorus source solution dropwise to the complexing agent solution obtained in step 1) simultaneously.

[0045] The present invention preferably mixes the complexing agent with the inorganic solvent to obtain a complexing agent solution. The operation of mixing the complexing agent with the inorganic solvent in the present invention is not particularly limited, and the technical scheme for preparing the mixed material well known to those skilled in the art can be used.

[0046] After obtaining the complexing agent solution, the present invention preferably simultaneously drops the rare earth salt solution, the barium salt / strontium salt solution and the phosphorus source solution into the complexing agent solution. The present invention adopts the dropping method to control the concentration of the solution, prevent sedimentation or agglomeration from causing phase separation between different components and thus causing uneven microstructure.

[0047] In the present invention, the dripping rate is preferably 3 to 5 mL / min, more preferably 4 to 5 mL / min. In the present invention, limiting the dripping rate within the above range can further improve the uniformity of particle size.

[0048] In the present invention, the dropping is preferably carried out under stirring conditions. The present invention has no particular limitation on the stirring operation, and the operation well known to those skilled in the art can be adopted.

[0049] In the present invention, the temperature of the complexing reaction is preferably 80-90°C; the time of the complexing reaction is preferably 2-8 hours. In the present invention, the metal cation and the complexing agent undergo a complexing reaction; limiting the temperature and time of the complexing reaction within the above range can improve the degree of the complexing reaction.

[0050] In the present invention, the complexation reaction is preferably carried out under stirring conditions. The present invention has no special limitation on the stirring operation, and conventional stirring known to those skilled in the art can be used.

[0051] After obtaining the sol, the present invention dries the sol to obtain a xerogel.

[0052] In the present invention, the drying preferably includes a first-stage drying and a second-stage drying performed sequentially; the temperature of the first-stage drying is preferably 80-90°C, more preferably 80-85°C; the time of the first-stage drying is preferably 20-30h, more preferably 24-28h; the temperature of the second-stage drying is preferably 110-130°C, more preferably 120-125°C; the time of the second-stage drying is preferably 10-20h, more preferably 15-20h. The present invention adopts a staged drying method, in which the first-stage drying can remove the residual solvent in the sol, and the second-stage drying can dry the sol into a loose and porous dry gel, preventing the gel from collapsing due to excessive heating in one step; limiting the temperature and time of the first-stage drying and the second-stage drying within the above range can prevent the gel from having severe volume shrinkage and structural damage.

[0053] The present invention has no particular limitation on the rate at which the temperature of the first stage drying is raised to the temperature of the second stage drying, and it can be adjusted as required.

[0054] After obtaining the dry gel, the present invention calcines the dry gel to obtain rare earth orthophosphate ceramic powder.

[0055] In the present invention, the dry gel is preferably ground before use. The present invention has no special limitation on the grinding operation, and the loose and porous dry gel can be ground into powder using a common mortar.

[0056] In the present invention, the calcination temperature is preferably 1000-1200°C, more preferably 1150-1190°C, more preferably 1160-1180°C, and most preferably 1170-1175°C; the calcination time is preferably 10-20h, more preferably 15-18h. The present invention limits the calcination temperature and time within the above ranges to ensure the purity of the ceramic powder.

[0057] In the present invention, the mechanism of heating to the calcination temperature is preferably to first heat to 400-500°C and then heat to the calcination temperature. The present invention adopts a staged heating method to remove excess organic matter in the dry gel.

[0058] In the present invention, the rate of heating to 400-500°C is preferably 1-2°C / min, more preferably 1°C / min; the rate of heating to the calcination temperature is preferably 3-5°C / min, more preferably 4-5°C / min. The present invention limits the heating rate to the above range to further remove excess organic matter in the dry gel.

[0059] After the calcination is completed, the present invention preferably cools the calcined product to obtain rare earth orthophosphate ceramic powder.

[0060] The present invention has no particular limitation on the cooling operation, and the cooling to room temperature may be performed by an operation well known to those skilled in the art.

[0061] The existing technology uses a solid phase reaction method to synthesize, which includes multiple processes such as raw material pre-sintering, grinding, ball milling and drying. The preparation process is cumbersome, resulting in reduced purity, and requires calcination synthesis at a higher temperature, which has strict equipment requirements and high energy consumption. The REM3P3O prepared by the preparation method provided by the present invention 12 The ceramic powder has a small particle size and is evenly distributed, the synthesis temperature is relatively low, the operation is simple, easy to control, the energy consumption is low, and it is easy to mass produce.

[0062] The present invention also provides rare earth orthophosphate ceramic powder prepared by the preparation method described in the above technical solution.

[0063] In the present invention, the particle size of the rare earth orthophosphate ceramic powder is preferably 10 to 25 μm, more preferably 13.062 to 20.357 μm; the particle size distribution is preferably 0.1 to 150 μm, more preferably 1 to 100 μm. The rare earth orthophosphate REM3P3O provided by the present invention 12 The ceramic powder has small particle size and is evenly distributed.

[0064] The present invention also provides the use of the rare earth orthophosphate ceramic powder described in the above technical solution in a thermal protective coating.

[0065] The present invention has no special limitation on the application operation of the rare earth orthophosphate ceramic powder in the thermal protection coating, and the application operation familiar to those skilled in the art can be adopted.

[0066] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. 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.

[0067] Example 1

[0068] Rare earth orthophosphate YBa3P3O 12 The preparation method of ceramic powder comprises the following steps:

[0069] (1) weighing raw materials according to the molar ratio of yttrium nitrate, barium nitrate, ammonium dihydrogen phosphate and citric acid of 1:3:3:4, and then dissolving them in deionized water respectively, stirring and dissolving to obtain clear yttrium nitrate solution, barium nitrate solution, ammonium dihydrogen phosphate solution and citric acid solution, and then simultaneously adding the yttrium nitrate solution, barium nitrate solution and ammonium dihydrogen phosphate solution to the citric acid solution at a rate of 3 mL / min, stirring at 80°C for complexation reaction for 5 hours, and obtaining a sol;

[0070] (2) placing the sol obtained in step (1) in an oven at 80° C. for 24 h, then heating to 120° C. for 20 h to fully dry the sol, thereby obtaining a dry gel containing a large number of micropores;

[0071] (3) Grind the dry gel obtained in step (2) into powder, place it in a muffle furnace, heat it to 400°C at 1°C / min, heat it to 1150°C at 4°C / min, keep it at that temperature for 15h, and then cool it to room temperature to obtain YBa3P3O 12 Ceramic powder.

[0072] The rare earth orthophosphate ceramic powder prepared in Example 1 was subjected to microscopic testing, and the results were as follows: Figure 1 As shown, Figure 1 This is the XRD pattern of the rare earth orthophosphate ceramic powder prepared in Example 1.

[0073] from Figure 1 It can be seen that the synthesized ceramic powder is pure phase YBa3P3O 12 Ceramic powder.

[0074] The particle size of the rare earth orthophosphate ceramic powder prepared in Example 1 was tested and analyzed. The results are as follows: Figure 2 As shown, Figure 2This is the particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 1.

[0075] from Figure 2 It can be seen that the rare earth orthophosphate ceramic powder prepared in Example 1 has uniform grain distribution, and the average grain size is calculated to be 15.344 μm.

[0076] Example 2

[0077] Rare earth orthophosphate NdBa3P3O 12 The preparation method of ceramic powder comprises the following steps:

[0078] (1) weighing raw materials according to the molar ratio of neodymium chloride, barium chloride, ammonium dihydrogen phosphate and citric acid of 1:3:3:4, and then dissolving them in deionized water respectively, stirring and dissolving to obtain clear neodymium chloride solution, barium chloride solution, ammonium dihydrogen phosphate solution and citric acid solution, and then dropping the neodymium chloride solution, barium chloride solution and ammonium dihydrogen phosphate solution into the citric acid solution at a rate of 5 mL / min, stirring at 80°C for complexation reaction for 5 hours, and obtaining a sol;

[0079] (2) placing the sol obtained in step (1) in an oven at 80° C., keeping the temperature for 24 h, raising the temperature to 125° C., keeping the temperature for 15 h to fully dry, and obtaining a dry gel having a porous structure;

[0080] (3) Grind the dry gel obtained in step (2) into powder, place it in a muffle furnace, heat it to 500°C at 1°C / min, heat it to 1160°C at 3°C / min, keep it at that temperature for 15h for calcination, and then cool it to room temperature to obtain NdBa3P3O 12 Ceramic powder.

[0081] The rare earth orthophosphate ceramic powder prepared in Example 2 was subjected to microscopic testing, and the results were as follows: Figure 1 As shown, Figure 1 This is the XRD pattern of the rare earth orthophosphate ceramic powder prepared in Example 2.

[0082] from Figure 1 It can be seen that the synthesized ceramic powder is pure phase NdBa3P3O 12 Ceramic powder.

[0083] The particle size of the rare earth orthophosphate ceramic powder prepared in Example 2 was tested and analyzed. The results are as follows: Figure 3 As shown, Figure 3 This is the particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 2.

[0084] from Figure 3It can be seen that the rare earth orthophosphate ceramic powder prepared in Example 2 has uniform grain distribution, and the average grain size is calculated to be 13.062 μm.

[0085] Example 3

[0086] Rare earth orthophosphate SmBa3P3O 12 The preparation method of ceramic powder comprises the following steps:

[0087] (1) weighing raw materials according to the molar ratio of samarium chloride, barium chloride, ammonium dihydrogen phosphate and citric acid of 1:3:3:4, and then dissolving them in deionized water respectively, stirring and dissolving to obtain clear samarium chloride solution, barium chloride solution, ammonium dihydrogen phosphate solution and citric acid solution, and then simultaneously adding the samarium chloride solution, barium chloride solution and ammonium dihydrogen phosphate solution to the citric acid solution at a rate of 5 mL / min, stirring at 85°C for complexation reaction for 3 hours, and obtaining a sol;

[0088] (2) placing the sol obtained in step (1) in an oven at 80° C., keeping the temperature for 24 h, raising the temperature to 130° C., keeping the temperature for 20 h to fully dry, and obtaining a dry gel having a porous structure;

[0089] (3) Grind the dry gel obtained in step (2) into powder, place it in a muffle furnace, heat it to 400°C at 1°C / min, heat it to 1175°C at 4°C / min, keep it at that temperature for 20 hours for calcination, and then cool it to room temperature to obtain SmBa3P3O 12 Ceramic powder.

[0090] The rare earth orthophosphate ceramic powder prepared in Example 3 was subjected to microscopic testing, and the results were as follows: Figure 1 As shown, Figure 1 This is the XRD pattern of the rare earth orthophosphate ceramic powder prepared in Example 3.

[0091] from Figure 1 It can be seen that the synthesized ceramic powder is pure phase SmBa3P3O 12 Ceramic powder.

[0092] The particle size of the rare earth orthophosphate ceramic powder prepared in Example 3 was tested and analyzed. The results are as follows: Figure 4 As shown, Figure 4 This is the particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 3.

[0093] from Figure 4 It can be seen that the rare earth orthophosphate ceramic powder prepared in Example 3 has uniform grain distribution, and the average grain size is calculated to be 13.343 μm.

[0094] Example 4

[0095] Rare earth orthophosphate GdBa3P3O 12 The preparation method of ceramic powder comprises the following steps:

[0096] (1) weighing raw materials according to the molar ratio of gadolinium chloride, barium nitrate, ammonium dihydrogen phosphate and citric acid of 1:3:3:8, and then dissolving them in deionized water respectively, stirring and dissolving to obtain clear gadolinium chloride solution, barium nitrate solution, ammonium dihydrogen phosphate solution and citric acid solution, and then simultaneously adding the gadolinium chloride solution, barium nitrate solution and ammonium dihydrogen phosphate solution to the citric acid solution at a rate of 5 mL / min, stirring at 90° C. for complexation reaction for 2 h to obtain a sol;

[0097] (2) placing the sol obtained in step (1) in an oven at 80° C., keeping the temperature for 24 h, raising the temperature to 130° C., keeping the temperature for 15 h to fully dry, and obtaining a dry gel having a porous structure;

[0098] (3) Grind the dry gel obtained in step (2) into powder, place it in a muffle furnace, heat it to 500°C at 1°C / min, heat it to 1160°C at 5°C / min, keep it at that temperature for 20 hours, and then cool it to room temperature to obtain GdBa3P3O 12 Ceramic powder.

[0099] The rare earth orthophosphate ceramic powder prepared in Example 4 was subjected to microscopic examination, and the results were as follows: Figure 1 As shown, Figure 1 This is the XRD pattern of the rare earth orthophosphate ceramic powder prepared in Example 4.

[0100] from Figure 1 It can be seen that the synthesized ceramic powder is pure phase GdBa3P3O 12 Ceramic powder.

[0101] The particle size of the rare earth orthophosphate ceramic powder prepared in Example 4 was tested and analyzed. The results are as follows: Figure 5 As shown, Figure 5 This is the particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 4.

[0102] from Figure 5 It can be seen that the rare earth orthophosphate ceramic powder prepared in Example 4 has uniform grain distribution, and the average grain size is calculated to be 13.951 μm.

[0103] Example 5

[0104] Rare earth orthophosphate HoBa3P3O 12 The preparation method of ceramic powder comprises the following steps:

[0105] (1) weighing raw materials according to the molar ratio of holmium chloride, barium acetate, ammonium dihydrogen phosphate and citric acid of 1:3:3:6, and then dissolving them in deionized water respectively, stirring and dissolving to obtain clear holmium chloride solution, barium acetate solution, ammonium dihydrogen phosphate solution and citric acid solution, and then simultaneously adding the holmium chloride solution, barium acetate solution and ammonium dihydrogen phosphate solution to the citric acid solution at a rate of 5 mL / min, stirring and performing complexation reaction at 90°C for 3 hours to obtain a sol;

[0106] (2) placing the sol obtained in step (1) in an oven at 80° C., keeping the temperature for 24 h, raising the temperature to 120° C., keeping the temperature for 10 h to fully dry, and obtaining a dry gel having a porous structure;

[0107] (3) Grind the dry gel obtained in step (2) into powder, place it in a muffle furnace, heat it to 400°C at 1°C / min, heat it to 1180°C at 5°C / min, keep it at that temperature for 10 hours, and then cool it to room temperature to obtain HoBa3P3O 12 Ceramic powder.

[0108] The rare earth orthophosphate ceramic powder prepared in Example 5 was subjected to microscopic testing, and the results were as follows: Figure 1 As shown, Figure 1 This is the XRD pattern of the rare earth orthophosphate ceramic powder prepared in Example 5.

[0109] from Figure 5 It can be seen that the synthesized ceramic powder is pure phase HoBa3P3O 12 Ceramic powder.

[0110] The particle size of the rare earth orthophosphate ceramic powder prepared in Example 5 was tested and analyzed. The results are as follows: Figure 6 As shown, Figure 6 This is the particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 5.

[0111] from Figure 6 It can be seen that the rare earth orthophosphate ceramic powder prepared in Example 5 has uniform grain distribution, and the average grain size is calculated to be 17.434 μm.

[0112] Example 6

[0113] Rare earth orthophosphate ErBa3P3O 12 The preparation method of ceramic powder comprises the following steps:

[0114] (1) weighing raw materials according to the molar ratio of erbium chloride, barium chloride, ammonium dihydrogen phosphate and citric acid of 1:3:3:4, and then dissolving them in deionized water respectively, stirring and dissolving to obtain clear erbium chloride solution, barium chloride solution, ammonium dihydrogen phosphate solution and citric acid solution, and then simultaneously adding the erbium chloride solution, barium chloride solution and ammonium dihydrogen phosphate solution to the citric acid solution at a rate of 5 mL / min, stirring and performing complexation reaction at 85°C for 3 hours, and obtaining a sol;

[0115] (2) placing the sol obtained in step (1) in an oven at 80° C., keeping the temperature for 24 h, raising the temperature to 120° C., keeping the temperature for 15 h to fully dry, thereby obtaining a dry gel having a porous structure;

[0116] (3) Grind the dry gel obtained in step (2) into powder, place it in a muffle furnace, heat it to 400°C at 1°C / min, heat it to 1170°C at 5°C / min, keep it at that temperature for 15h for calcination, and then cool it to room temperature to obtain ErBa3P3O 12 Ceramic powder.

[0117] The rare earth orthophosphate ceramic powder prepared in Example 6 was subjected to microscopic testing, and the results were as follows: Figure 1 As shown, Figure 1 This is the XRD pattern of the rare earth orthophosphate ceramic powder prepared in Example 6.

[0118] from Figure 1 It can be seen that the synthesized ceramic powder is pure phase ErBa3P3O 12 Ceramic powder.

[0119] The particle size of the rare earth orthophosphate ceramic powder prepared in Example 6 was tested and analyzed. The results are as follows: Figure 7 As shown, Figure 7 This is the particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 6.

[0120] from Figure 7 It can be seen that the rare earth orthophosphate ceramic powder prepared in Example 6 has uniform grain distribution, and the average grain size is calculated to be 20.357 μm.

[0121] Example 7

[0122] Rare earth orthophosphate TmBa3P3O 12 The preparation method of ceramic powder comprises the following steps:

[0123] (1) weighing raw materials according to the molar ratio of thulium chloride, barium acetate, ammonium dihydrogen phosphate and citric acid of 1:3:3:4, and then dissolving them in deionized water respectively, stirring and dissolving to obtain clear thulium chloride solution, barium acetate solution, ammonium dihydrogen phosphate solution and citric acid solution, and then simultaneously adding the thulium chloride solution, barium acetate solution and ammonium dihydrogen phosphate solution to the citric acid solution at a rate of 5 mL / min, stirring at 85°C for 4 hours to carry out complexation reaction, and obtaining a sol;

[0124] (2) placing the sol obtained in step (1) in an oven at 80° C., keeping the temperature for 24 h, raising the temperature to 120° C., keeping the temperature for 20 h to fully dry, and obtaining a dry gel having a porous structure;

[0125] (3) Grind the dry gel obtained in step (2) into powder, place it in a muffle furnace, heat it to 400°C at 1°C / min, heat it to 1190°C at 5°C / min, keep it at that temperature for 20 hours, and then cool it to room temperature to obtain TmBa3P3O 12 Ceramic powder.

[0126] The rare earth orthophosphate ceramic powder prepared in Example 7 was subjected to microscopic examination, and the results were as follows: Figure 1 As shown, Figure 1 This is the XRD pattern of the rare earth orthophosphate ceramic powder prepared in Example 7.

[0127] from Figure 1 It can be seen that the synthesized ceramic powder is pure phase TmBa3P3O 12 Ceramic powder.

[0128] The particle size of the rare earth orthophosphate ceramic powder prepared in Example 7 was tested and analyzed. The results are as follows: Figure 8 As shown, Figure 8 This is the particle size distribution diagram of the rare earth orthophosphate ceramic powder prepared in Example 7.

[0129] from Figure 8 It can be seen that the rare earth orthophosphate ceramic powder prepared in Example 7 has uniform grain distribution, and the average grain size is calculated to be 20.037 μm.

[0130] Comparative Example 1

[0131] The calcination conditions in step (3) of Example 1 were changed to 800°C for 20 h, while other conditions remained unchanged to obtain YBa3P3O 12 Ceramic powder.

[0132] The rare earth orthophosphate ceramic powder prepared in Comparative Example 1 was subjected to microscopic testing, and the results were as follows: Fig. 9 As shown, Fig. 9 This is the XRD diagram of the rare earth orthophosphate ceramic powder prepared in Comparative Example 1.

[0133] from Fig. 9 It can be seen that pure YBa3P3O was not obtained under this calcination condition. 12 Physical phase.

[0134] Comparative Example 2

[0135] The calcination conditions in step (3) of Example 2 were changed to 850°C for 20 h, while other conditions remained unchanged to obtain NdBa3P3O 12 Ceramic powder.

[0136] The rare earth orthophosphate ceramic powder prepared in Comparative Example 2 was subjected to microscopic testing, and the results were as follows: Fig. 9 As shown, Fig. 9 This is the XRD diagram of the rare earth orthophosphate ceramic powder prepared in Comparative Example 2.

[0137] from Fig. 9 It can be seen that pure phase NdBa3P3O was not obtained under this calcination condition. 12 Physical phase.

[0138] Comparative Example 3

[0139] The calcination conditions in step (3) of Example 3 were changed to 900°C for 20 h, while other conditions remained unchanged to obtain SmBa3P3O 12 Ceramic powder.

[0140] The rare earth orthophosphate ceramic powder prepared in Comparative Example 3 was subjected to microscopic testing, and the results were as follows: Fig. 9 As shown, Fig. 9 This is the XRD diagram of the rare earth orthophosphate ceramic powder prepared in Comparative Example 3.

[0141] from Fig. 9 It can be seen that pure phase SmBa3P3O was not obtained under this calcination condition. 12 Physical phase.

[0142] Comparative Example 4

[0143] The calcination conditions in step (3) of Example 4 were changed to 950°C for 20 h, while other conditions remained unchanged to obtain GdBa3P3O 12 Ceramic powder.

[0144] The rare earth orthophosphate ceramic powder prepared in Comparative Example 4 was subjected to microscopic testing, and the results were as follows: Fig. 9 As shown, Fig. 9 This is the XRD diagram of the rare earth orthophosphate ceramic powder prepared in Comparative Example 4.

[0145] from Fig. 9 It can be seen that no pure phase of GdBa3P3O was obtained under this calcination condition.12 Physical phase.

[0146] It can be seen from the above embodiments and comparative examples that the rare earth orthophosphate ceramic powder provided by the present invention has a small particle size and is evenly distributed.

[0147] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing rare earth orthophosphate ceramic powder, The following steps are involved: (1) mixing a rare earth salt solution, a barium salt / strontium salt solution, a phosphorus source solution, a complexing agent and an inorganic solvent to carry out a complexing reaction to obtain a sol; (2) drying the sol obtained in step (1) to obtain a xerogel; (3) calcining the dry gel obtained in step (2) to obtain rare earth orthophosphate ceramic powder.

2. The preparation method according to claim 1, It is characterized in that The rare earth salt in step (1) includes rare earth chloride or rare earth nitrate.

3. The preparation method according to claim 1, It is characterized in that The barium salt in step (1) includes barium chloride, barium nitrate or barium acetate; the strontium salt includes strontium chloride, strontium nitrate or strontium acetate.

4. The preparation method according to claim 1, It is characterized in that The phosphorus source in step (1) includes (NH 4 ) 2 HPO 4 or NH 4 H 2 PO 4 .

5. The preparation method according to claim 1, It is characterized in that The complexing agent in step (1) is citric acid.

6. The preparation method according to claim 1, It is characterized in that In the step (1), the molar ratio of the rare earth salt, the barium salt / strontium salt, the phosphorus source and the complexing agent is 1:3:3:(3.5-8).

7. The preparation method according to claim 1, It is characterized in that The temperature of the complexation reaction in step (1) is 80-90° C., and the time of the complexation reaction is 2-8 hours.

8. The preparation method according to claim 1, It is characterized in that The drying in step (2) includes first-stage drying and second-stage drying performed sequentially.

9. Rare earth orthophosphate ceramic powder prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the rare earth orthophosphate ceramic powder according to claim 9 in thermal protective coatings.

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