CN-118546548-B - Low-thermal-conductivity high-temperature-resistant nano layered calcium niobate thermal-insulation coating with ordered structure and preparation method thereof

Abstract

The invention provides a low-thermal-conductivity high-temperature-resistant and structurally ordered nano layered calcium niobate heat-insulating coating, which has the advantages of low thermal conductivity and good thermal stability, and is suitable for being applied to a substrate with the heat-resistant temperature higher than 500 ℃. Meanwhile, the invention also provides a preparation method of the thermal insulation coating, which has the advantages of simple process, easy operation and high efficiency, and is suitable for large-scale application.

Inventors

• YUAN HUIYU
• WANG WENJUAN
• YANG DAOYUAN

Assignees

• 郑州大学

Dates

Publication Date

20260508

Application Date

20240514

Claims (6)

1. 1. A low-thermal-conductivity high-temperature-resistant nano layered calcium niobate heat-insulating coating with ordered structure is characterized by being applied to application scenes with the heat-resistant temperature higher than 500 ℃; the preparation method of the thermal insulation coating comprises the following steps: The preparation method of the precursor solution for the low-thermal-conductivity high-temperature-resistant structurally ordered nano layered calcium niobate thermal-insulation coating comprises the following preparation steps: mixing the potassium salt solution with the calcium niobate nanosheet suspension to obtain a mixed solution, and adding ethanol into the mixed solution to obtain a precursor solution; The preparation method of the low-thermal-conductivity high-temperature-resistant and structurally ordered nano layered calcium niobate thermal-insulation coating comprises the steps of preheating a substrate, spraying a precursor solution on the surface of the substrate after reaching a target temperature, and annealing the substrate at 300-500 ℃ after the spraying is finished.
2. 2. The thermal barrier coating of claim 1, wherein the potassium salt solution is an aqueous solution of K 2 CO 3 、K 2 SO 4 , KCl, or CH 3 COOK, the concentration of the potassium salt solution is 0.05-0.1 mol/L, the concentration of the calcium niobate nanosheet suspension is 0.12-0.50 g/L, the volume ratio of the potassium salt solution to the calcium niobate nanosheet suspension is 1 (15-40), and the volume ratio of the ethanol to the mixed solution is (1-8): 1.
3. 3. The method according to claim 1, wherein the step of preparing the precursor solution comprises dropwise adding the potassium salt solution thereto while stirring the calcium niobate nanosheet suspension.
4. 4. The thermal barrier coating of claim 1, wherein the substrate is preheated to a temperature of 120-200 ℃ for a time period of 1-2 min.
5. 5. The thermal barrier coating of claim 1, wherein the coating is performed using an air pressure spray apparatus comprising an inert gas supply, an injection pump, an injector, an atomizer, and a heating stage, the substrate being placed on the heating stage with the atomizer facing the substrate.
6. 6. The thermal barrier coating of claim 5, wherein the distance between the atomizer and the substrate is 10-20 cm, the gas flow rate of the gas of the pneumatic spraying device is 10.0-17.5L/min, and the injection rate of the precursor solution is 0.3-1.0 mL/min during spraying.

Description

Low-thermal-conductivity high-temperature-resistant nano layered calcium niobate thermal-insulation coating with ordered structure and preparation method thereof Technical Field The invention relates to a layered nano oxide, in particular to a low-thermal-conductivity high-temperature-resistant and structurally ordered nano layered calcium niobate heat-insulating coating and a preparation method thereof. Background The calcium niobate is a widely applied semiconductor material, such as bismuth titanate-calcium niobate solid solution disclosed in China patent CN106478090A, which is used for capacitors, resonators, filters, circuit substrates, integrated circuits and the like, self-frequency doubling laser crystal doped with neodymium calcium niobate disclosed in China patent CN1847471A, which is used for solid lasers in spectroscopy, biomedicine and military fields, and calcium niobate-based self-activated luminescent material disclosed in China patent CN105778908A, which is applied to illumination and display fields and the like, has few reports on the performance of the calcium niobate in terms of heat insulation, and particularly, layered nano calcium niobate has stronger anisotropy, and the layered structure of the layered nano calcium niobate needs to be prepared into an ordered stacked structure, but the preparation of the structure is difficult, and the application of the layered nano calcium niobate in the heat insulation field is limited. The layer-by-layer self-assembly (LbL) technology is a simple and low-cost multilayer forming technology, and an ordered structure is obtained through two-dimensional nano-sheet recombination, however, the layer-by-layer self-assembly technology has the defects of low efficiency, difficult thick film preparation and the like. In addition, the wet process of assembling two-dimensional nano-sheets layer by layer to prepare the structure ordered nano-layered coating can reduce the thermal stability of the coating, and is one of the challenges faced in preparing the high-temperature resistant layered ordered coating. In order to solve the above problems, an ideal technical solution is always sought. Disclosure of Invention The invention aims at overcoming the defects of the prior art, and provides a low-thermal-conductivity high-temperature-resistant nano layered calcium niobate heat-insulating coating with ordered structure and a preparation method thereof. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: A low thermal conductivity, high temperature resistant and ordered structure nanometer layered calcium niobate thermal insulation coating is applied to a substrate with a heat resistant temperature higher than 500 ℃. The substrate is Si, glass, 718 nickel alloy or galvanized iron sheet. A method of preparing the thermal barrier coating, comprising the steps of: Preheating the substrate, spraying the precursor solution on the surface of the substrate after preheating, and annealing the substrate at 300-500 ℃ after spraying, wherein the annealing heat preservation time is 3-4h, and the heating rate of annealing is 5-10 ℃ per min. The preparation method of the precursor solution comprises the steps of mixing a potassium salt solution with a calcium niobate nanosheet suspension to obtain a mixed solution, and adding ethanol into the mixed solution to obtain the precursor solution. The preparation method of the calcium niobate nanosheet suspension comprises the steps of dispersing solid acid (calcium hydrogen niobate HCNO) powder in a water ratio of 0.1g to 20ml, adding 7.5 mu L of tetrabutylammonium hydroxide TBAOH as organic base to strip the layered solid acid HCNO, and stirring for 4 days to obtain the calcium niobate suspension. The potassium salt solution is an aqueous solution of K 2CO3、K2SO4, KCl or CH 3 COOK, the concentration of the potassium salt solution is 0.05-0.1mol/L, the concentration of the calcium niobate nanosheet suspension is 0.12-0.50 g/L, the volume ratio of the potassium salt solution to the calcium niobate nanosheet suspension is 1 (15-40), and the volume ratio of the ethanol to the mixed solution is 1-8:1. In the preparation step of the precursor solution, the potassium salt solution was dropwise added thereto while stirring the calcium niobate nanosheet suspension. The preheating temperature of the substrate is 120-200 ℃ and the preheating time is 1-2min. The air pressure spraying device is adopted for spraying, and comprises an inert gas supply part, an injection pump, an injector, an atomization nozzle and a heating table, wherein the substrate is placed on the heating table, and the atomization nozzle is opposite to the substrate. The distance between the atomizing nozzle and the substrate is 10-20cm. In the spraying process, the air flow rate of the air pressure spraying device is 10.0-17.5L/min, and the injection rate of the precursor solution is 0.3-1.0mL/min. Compared with the prior art,