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CN-122010584-A - High-temperature stable nano zirconia-based heat insulation ceramic material and preparation method thereof

CN122010584ACN 122010584 ACN122010584 ACN 122010584ACN-122010584-A

Abstract

The invention discloses a high-temperature stable nano zirconia-based heat insulation ceramic material and a preparation method thereof. The method comprises the steps of mixing ZrOCl 2 ·8H 2 O solution with Y (NO 3 ) 3 solution), adding a citric acid complexing agent and high-valence transition metal alkoxide (Nb or Ta), adjusting pH to 8.5-10.5 to form polymeric complex nanosol, introducing La or Gd rare earth components, obtaining a closed nanopore precursor through unidirectional freeze drying, presintering at 500-700 ℃, and sintering at 1250-1350 ℃.

Inventors

  • LIU HEYI
  • WANG TIANCHI
  • ZHANG MIN

Assignees

  • 南京理工大学
  • 江苏和腾热工装备科技有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (8)

  1. 1. The preparation method of the high-temperature stable nano zirconia-based heat insulation ceramic material is characterized by comprising the following steps of: S1, adding ZrOCl 2 ·8H 2 O solution into Y (NO 3 ) 3 solution, enabling Y 2 O 3 to account for 3-8 mol% of 2 mol% of ZrO, adding a multidentate organic acid complexing agent, introducing high-valence transition metal alkoxide, heating and stirring at 60-80 ℃, and then adjusting the pH of the solution to 8.5-10.5 to form a polymeric complex nanosol precursor; s2, introducing a rare earth component which can generate solid phase reaction with zirconia in the sintering process to generate a pyrochlore structure into the polymerization complex nanosol precursor; s3, performing unidirectional freezing treatment and freeze drying on the obtained system to form a nano-pore precursor structure; s4, presintering the obtained precursor at 500-700 ℃, and sintering at 1250-1350 ℃ to obtain the high-temperature stable nano zirconia-based heat insulation ceramic material.
  2. 2. The method according to claim 1, wherein the ZrOCl 2 ·8H 2 O solution is 0.5-1.5 mol/L.
  3. 3. The method of claim 1, wherein the multidentate organic acid is citric acid and the ratio of citric acid to the total molar amount of Zr 4+ and Y 3+ is 1.2-1.8:1.
  4. 4. The method of claim 3, wherein the high-valence transition metal alkoxide is Nb (OEt) 5 or Ta (OEt) 5 , and the mass ratio of the high-valence transition metal alkoxide to citric acid is 0.1-0.8:1.
  5. 5. The method according to claim 1, wherein the rare earth component is La or Gd, and the addition amount thereof is 5-20 wt% of the final ceramic mass.
  6. 6. The method of claim 1, wherein the unidirectional freezing treatment temperature is-20 ℃ to-60 ℃, the freezing time is 4-12 hours, and the freeze drying time is 24-48 hours.
  7. 7. The method according to claim 1, wherein the sintering temperature rise rate is 5-15 ℃.
  8. 8. A high temperature stable nano zirconia-based insulating ceramic material prepared based on the preparation method of claim 1.

Description

High-temperature stable nano zirconia-based heat insulation ceramic material and preparation method thereof Technical Field The invention relates to the technical field of heat-insulating ceramic materials, in particular to a high-temperature stable nano zirconia-based heat-insulating ceramic material and a preparation method thereof. Background The zirconia-based heat insulation ceramic material is widely applied to the fields of aeroengines, gas turbines, high-temperature industrial kilns and the like due to the excellent high-temperature mechanical properties and relatively low heat conductivity. The stabilized zirconia system represented by Y 2O3 stabilized ZrO 2 (YSZ) can stabilize a tetragonal phase or a cubic phase structure in a range from room temperature to middle temperature and high temperature by introducing 3-8 mol% of Y 2O3 solid solution into a ZrO 2 lattice, and can remarkably inhibit the volume expansion instability caused by martensitic phase transformation. The system has higher thermal expansion coefficient and good matching property with a metal matrix, and simultaneously relies on the phase change toughening effect generated by stress-induced tetragonal phase-to-monoclinic phase transformation, so that the system has certain fracture toughness advantage. In addition, the YSZ powder preparation, molding and sintering process system is mature, and the large-scale production is easy to realize, so that the YSZ powder preparation, molding and sintering process system becomes a main flow technical route in the field of high-temperature heat-insulating ceramic materials for a long time. Along with the development of nanotechnology, the application of the nano zirconia powder and the ceramic body thereof is gradually promoted, and the grain boundary quantity and interface phonon scattering enhancement effect brought by the nano structure are increased, so that the material shows lower heat conductivity and better microstructure uniformity in an initial state, thereby further improving the heat insulation potential. However, the existing nano zirconia-based heat insulation ceramic taking YSZ as a core still has a remarkable structural stability problem under the long-term service condition of more than 1200 ℃. Firstly, the nano material has higher specific surface area and interface energy, grain boundary migration and substance diffusion acceleration easily occur in a high-temperature environment, so that grains grow up rapidly and pores shrink, the original nanoscale interface structure is destroyed, and the phonon scattering capability is further weakened, so that the thermal conductivity is gradually increased along with the service time. Secondly, under the condition of high-temperature long-time heat exposure, the distribution of oxygen vacancies tends to be in thermodynamic equilibrium, the local stress field is changed, part of tetragonal phases can still be converted into monoclinic phases, the volume effect and microcrack initiation are initiated, and the structural reliability is affected. In addition, as the grain coarsening and defect structure decrease, the interface heat-resistant effect inside the material decreases, and the heat-insulating performance is difficult to maintain for a long period of time. Therefore, how to inhibit abnormal growth of crystal grains of the nano zirconia material, stabilize the tetragonal phase structure and keep the characteristics of low heat conduction microstructure under the high-temperature long-term service condition, realize cooperative promotion of heat insulation performance and structural stability, and become a key technical problem to be solved in the field of the current zirconia-based heat insulation ceramic material. Disclosure of Invention The application provides a preparation method of a high-temperature stable nano zirconia-based heat insulation ceramic material, which comprises the following steps: S1, dissolving ZrOCl 2·8H2 O in deionized water to form a zirconium salt solution with the concentration of 0.5-1.5 mol/L, adding Y (NO 3)3 solution to enable Y 2O3 to account for 3-8 mol% of 2 mol% of ZrO, adding a multidentate organic acid complexing agent, introducing high-valence transition metal alkoxide, heating and stirring at the temperature of 60-80 ℃ to form a polymerization complex nanosol precursor with adjustable surface electrochemical characteristics; s2, introducing a rare earth component which can generate a solid phase reaction with zirconia in the sintering process to generate a pyrochlore structure into the sol system; s3, performing unidirectional freezing treatment and freeze drying on the obtained system to form a nano-pore precursor structure; s4, presintering the obtained precursor at 500-700 ℃, and sintering at 1250-1350 ℃ to obtain the high-temperature stable nano zirconia-based heat insulation ceramic material. In the step S1, zr 4+ and Y 3+ form a stable polymerization complexing network under the action