Zirconium oxide doped rare earth tantalate niobate high-toughness ceramic powder and preparation method thereof

Abstract

The invention belongs to the field of thermal barrier coating ceramic powder preparation, and particularly relates to zirconium oxide doped rare earth tantalate niobate high-toughness ceramic powder and a preparation method thereof. According to the zirconium oxide doped rare earth tantalate niobate high-toughness ceramic powder, the molecular formula of the ceramic powder is (RETa1 / 2Nb1 / 2O4) x (ZrO2) 1-x, and x is larger than 0.5 and smaller than 1; rE is one or a mixture of more of Y, Yb, Gd, La, Nd, Lu, Sm, Eu, Dy and Er. The doping of rare earth elements is beneficial to formation of lattice distortion and the like to improve the thermodynamic property of the powder material, and further the doping of zirconium oxide is beneficial to improvement of the fracture toughness of the powder material; according to the technical scheme, high-toughness zirconium oxide doped rare earth tantalate niobate thermal barrier coating ceramic material powder is used for the first time, a wider space is provided for regulation and control of the structure and performance of a thermal barrier coating material through the multi-component solid solution effect of tantalate niobate, and the microstructure and macroscopic performance of the material are remarkably changed by introducing external atoms or defects in doping.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of thermal barrier coating ceramic powder preparation, and particularly relates to a zirconia-doped rare earth tantalum niobate high-toughness ceramic powder and a preparation method thereof. BACKGROUND

[0002] Thermal barrier coating (TBCs) is one of the key core technologies of advanced aero-engines, and as the most feasible technology to improve the service temperature of the engine, has become an indispensable thermal protection material for the hot end components such as high-pressure turbine blades of the aero-engine, and greatly determines the performance and development level of the engine. The thermal barrier coating is listed as a core key technology in the major propulsion plan of the world's aviation powers, and China has also listed the thermal barrier coating as a key technology required by the "two machines".

[0003] The rare earth tantalate ceramic material has a ferroelastic toughening effect similar to YSZ, and the ceramic material has extremely low thermal conductivity, and is a new generation of thermal barrier coating material with great potential. For most oxide candidate materials, such as RE2Zr2O7, REPO4 and the like, they generally exhibit superior thermal stability and heat insulation performance compared with YSZ materials, but their mechanical properties, especially the fracture toughness, cannot meet the requirements of TBCs, and the fracture toughness is one of the core indicators of the performance of thermal barrier coating (TBCs), and directly affects the thermal shock resistance, crack propagation resistance and service life of the coating. A high-toughness coating can relieve stress concentration through plastic deformation or crack deflection mechanism, and avoid transverse cracks or peeling failure caused by thermal shock; insufficient toughness will accelerate the cracking and peeling of the thermal growth oxide (TGO) layer. SUMMARY

[0004] To solve the above technical problems, the application aims to provide a zirconia-doped rare earth tantalum niobate high-toughness ceramic powder and a preparation method thereof.

[0005] To achieve the above application purposes, the application provides the following technical solutions. A zirconia-doped rare earth tantalum niobate high-toughness ceramic powder, the molecular formula of the ceramic powder is (RETa 1 / 2 Nb 1 / 2 O4)x(ZrO2) 1-x , wherein x is greater than 0.5 and less than 1; RE is one or a mixture of several of Y, Yb, Gd, La, Nd, Lu, Sm, Eu, Dy, Er.

[0006] A preparation method of a zirconia-doped rare earth tantalum niobate high-toughness ceramic powder, comprising the following steps: (1)According to the molar ratio, take the rare earth oxide (RE2O3) with purity greater than ≥ 99%, niobium pentoxide (Nb2O5), tantalum pentoxide (Ta2O5); wherein the molar ratio of niobium pentoxide (Nb2O5) and tantalum pentoxide (Ta2O5) is taken, and the total amount of rare earth oxide (RE2O3) is taken in the molar ratio of niobium pentoxide (Nb2O5) and tantalum pentoxide (Ta2O5), to ensure the generation of RETa 1 / 2 Nb 1 / 2 O4; (2) Add alcohol solvent and zirconium oxide ball milling ball, adopt planetary ball mill to mix raw materials, dry, sieve to obtain mixed uniform powder A; (3) Put the powder A obtained in step 2 into a high temperature furnace for high temperature solid phase reaction, the reaction temperature is 1350-1500℃, and the holding time is 6h, to obtain the rare earth tantalum niobate powder B with uniform composition; (4) Add submicron or nanometer zirconium oxide to the powder B obtained in step 3 according to the mass ratio (wt%) less than 50%, adopt planetary ball mill to mix raw materials, dry, sieve, and then carry out high temperature solid phase 1350-1500℃, holding time 6h, to prepare high toughness zirconium oxide doped rare earth tantalum niobate thermal barrier coating ceramic material powder.

[0007] The rare earth oxide RE2O3 powder is any one or several of gadolinium oxide (Gd2O3), yttrium oxide (Y2O3), ytterbium oxide (Yb2O3), neodymium oxide (Nd2O3), samarium oxide (Sm2O3), europium oxide (Eu2O3), dysprosium oxide (Dy2O3), erbium oxide (Er2O3) and lutetium oxide (Lu2O3).

[0008] The application provides a zirconium oxide doped rare earth tantalum niobate high toughness ceramic powder and a preparation method thereof; the doping of rare earth elements is beneficial to the formation of lattice distortion and the improvement of the thermodynamic performance of the powder material; the further doping of zirconium oxide is beneficial to the improvement of the fracture toughness of the powder material; the technical scheme is the first high toughness zirconium oxide doped rare earth tantalum niobate thermal barrier coating ceramic material powder, the multi-component solid solution of tantalum niobate provides a wider space for the structure and performance adjustment of the thermal barrier coating material, the doping significantly changes the microstructure and macroscopic performance of the material by introducing foreign atoms or defects.

[0009] The doping of zirconium oxide can refine the grain size, realize atomic solid solution strengthening and phase transformation toughening, and effectively improve the fracture toughness of the material.

[0010] The technical scheme provided by the application can produce interface thermal resistance at the interface between two phases due to the significant crystal structure difference between the two phases, which leads to the enhancement of phonon scattering and the reduction of thermal conductivity, and is expected to be applied in the field of thermal barrier coatings.

[0011] The purity of the powder raw material is greater than or equal to 99%, which is beneficial to reduce the influence of impurities on the preparation of the powder.

[0012] The used toughened zirconia should be submicron and nano zirconia, and experiments show that other particle sizes cannot effectively perform phase transition toughening, which is a key to trigger phase transition.

[0013] The solid-phase synthesis is a two-step synthesis method, and the beneficial effects are as follows: the inventors know through a large number of experiments that the two-step synthesis is beneficial to the synthesis of rare earth tantalum niobate (self-ferroelastic phase transition toughening), and also prevents the reaction of rare earth oxide RE2O3 and zirconia to generate zirconate, so as to prevent the realization of zirconia doped toughening. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The XRD graph of the high-toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder obtained in Example 1 of the application.

[0015] Figure 2 The SEM graph and crack fracture of the high-toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder obtained in Example 1 of the application. DETAILED DESCRIPTION

[0016] The application will be further described below in combination with examples, and the modes of the application include but are not limited to the following examples.

[0017] Example 1 is as follows: The preparation method of the high-toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder in this example is as follows: Ta2O5 powder, Nb2O5 powder, Y2O3 powder and Gd2O3 powder raw materials (the purity of the used raw materials is greater than or equal to 99%) are weighed according to a molar ratio of 1:1:1:1, and the powders are put into alcohol, zirconia balls are used as ball milling medium, and then the solution is mixed and subjected to planetary ball milling, the ball milling time is 12 h, and the rotating speed is 350 r / min. After ball milling, the powders are placed in an oven for drying, the drying temperature is 85℃, the drying time is 12 h, and sieving is performed. Then the obtained powders are placed in a high-temperature furnace, a temperature is set, and the powders are kept at 1350℃ for 6 h, and then a rare earth tantalum niobate ceramic powder is obtained, submicron or nano zirconia is added to the powder B obtained in step 3 according to a proportion of 9:1, the raw materials are mixed by using planetary ball milling, and after drying and sieving, high-temperature solid-phase synthesis is performed at 1350-1500℃, and the high-toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder (Y 1 / 2 Gd 1 / 2 Ta 1 / 2 Nb 1 / 2 O4) 9 / 10 (ZrO2) 1 / 10 , and the fracture toughness can reach 3.6 Mpa·m 1 / 2.

[0018] From Figure 1 It can be seen that the zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder is synthesized, from Figure 2 It can be seen that the grain is refined, the crack propagation is divided into intergranular fracture and transgranular fracture, and the powder exists ferroelastic domain, which significantly improves the fracture toughness.

[0019] Example 2 is as follows: The preparation method of the high-toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder of the embodiment is as follows: Ta2O5 powder, Nb2O5 powder, Y2O3 powder and Yb2O3 powder raw materials (the purity of the raw materials used is ≥99%) are weighed in a molar ratio of 1:1:1:1, and the powders are put into alcohol. Zirconia balls are used as the ball milling medium, and then the solution is mixed and subjected to planetary ball milling. The ball milling time is 8h, and the rotation speed is 300r / min. After ball milling, it is placed in an oven for drying. The drying temperature is 75℃, the drying time is 12h, and sieving is performed. Then the obtained powder is placed in a high temperature furnace, and a temperature is set. After being kept at 1350℃ for 6h, a rare earth tantalum niobate ceramic powder is obtained. After cooling in the furnace, submicron or nanoscale zirconia is added to the powder B obtained in step 3 in a proportion of 9:1. The raw materials are mixed by planetary ball milling, dried, sieved, and then subjected to high-temperature solid phase at 1350℃ for 6h to obtain the high-toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder (Y 1 / 2 Yb 1 / 2 Ta 1 / 2 Nb 1 / 2 O4) 9 / 10 (ZrO2) 1 / 10 .

[0020] Example 3 is as follows: The preparation method of the high-toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder of the embodiment is as follows: Ta2O5 powder, Nb2O5 powder, Y2O3 powder and Yb2O3 powder raw materials (the purity of the raw materials used is ≥99%) are weighed in a molar ratio of 1:1:1:1, and the powders are put into alcohol. Zirconia balls are used as the ball milling medium, and then the solution is mixed and subjected to planetary ball milling. The ball milling time is 8h, and the rotation speed is 300r / min. After ball milling, it is placed in an oven for drying. The drying temperature is 75℃, the drying time is 12h, and sieving is performed. Then the obtained powder is placed in a high temperature furnace, and a temperature is set. After being kept at 1350℃ for 6h, a rare earth tantalum niobate ceramic powder is obtained. After cooling in the furnace, submicron or nanoscale zirconia is added to the powder B obtained in step 3 in a proportion of 9:1. The raw materials are mixed by planetary ball milling, dried, sieved, and then subjected to high-temperature solid phase at 1350℃ for 6h to obtain the high-toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder (Y 1 / 3 Nd2 / 3 Ta 1 / 2 Nb 1 / 2 O4) 7 / 10 (ZrO2) 3 / 10 .

[0021] The thermal barrier coating of Example 4 is as follows: The high toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder of the present example is prepared by taking Ta2O5 powder, Nb2O5 powder, Y2O3 powder and Dy2O3 powder raw materials (the purity of the raw materials used is ≥ 99%) in a molar ratio of 2:2:1:3, and placing the powders in alcohol, using zirconia balls as the ball milling medium, and then mixing the solution and performing planetary ball milling for 12 h at a speed of 400 r / min. After ball milling, it is placed in an oven for drying at a drying temperature of 85℃ for 10 h and sieved. Then the obtained powder is placed in a high temperature furnace by setting the temperature, and after being kept at 1450℃ for 8 h, a rare earth tantalum niobate ceramic powder is obtained. After cooling in the furnace, submicron or nanoscale zirconia is added to the powder B obtained in step 3 in a proportion of 7:3, and the raw materials are mixed by planetary ball milling, dried, sieved and then subjected to high temperature solid phase at 1500℃ for 10 h to obtain the high toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material powder (Y 1 / 4 Dy 3 / 4 Ta 1 / 2 Nb 1 / 2 O4) 7 / 10 (ZrO2) 3 / 10 .

[0022] In summary, the technical solution provided by the present application is prepared by doping zirconia into tantalum niobate, and provides a high toughness zirconia doped rare earth tantalum niobate thermal barrier coating ceramic material and a preparation method thereof, and the fracture toughness thereof can reach 3.6 Mpa·m 1 / 2 .

[0023] For those skilled in the art, without departing from the technical solution concept of the present application, a number of modifications and improvements can be made, which should be considered as the protection scope of the present application, and these will not affect the effect and practicality of the patent implementation.

Claims

1. A zirconium oxide-doped rare earth tantalum niobate high-toughness ceramic powder, characterized in that: The molecular formula of the ceramic powder is (RETa). 1 / 2 Nb 1 / 2 O4)x(ZrO2) 1-x (where x is greater than 0.5 and less than 1); RE is one or a mixture of several of Y, Yb, Gd, La, Nd, Lu, Sm, Eu, Dy, Er.

2. A method for preparing the zirconium oxide-doped rare earth tantalum niobate high-toughness ceramic powder according to claim 1, characterized in that... Includes the following steps: (1) Weigh rare earth oxides (RE2O3), niobium pentoxide (Nb2O5), and tantalum pentoxide (Ta2O5) with a purity greater than or equal to 99% according to the specified ratio; wherein niobium pentoxide (Nb2O5) and tantalum pentoxide (Ta2O5) are weighed in equimolar ratio, and the total amount of rare earth oxides (RE2O3) is weighed in equimolar ratio with the total amount of niobium pentoxide (Nb2O5) and tantalum pentoxide (Ta2O5) to ensure the formation of RETa 1 / 2 Nb 1 / 2O4; (2) Add alcohol solvent and zirconium oxide ball milling balls, mix the raw materials by planetary ball milling, and obtain uniformly mixed powder A by drying and sieving; (3) The powder A obtained in step 2 is placed in a high-temperature furnace for high-temperature solid-phase reaction at a reaction temperature of 1350-1500℃ and kept at the temperature for 6 hours to obtain rare earth tantalum niobate powder B with uniform composition. (4) Add submicron or nano-sized zirconium oxide at a mass ratio of less than 50% to powder B obtained in step 3, mix the raw materials by planetary ball milling, dry and sieve, and then perform high-temperature solid phase treatment at 1350-1500℃ for 6 hours to obtain high-toughness zirconium oxide doped rare earth tantalum niobate thermal barrier coating ceramic material powder.

3. The method for preparing zirconium oxide-doped rare earth tantalum niobate high-toughness ceramic powder as described in claim 2, characterized in that: In step (1), the purity of RE2O3 powder, Ta2O5 powder, and Nb2O5 powder is not less than 99%.

4. The method for preparing zirconium oxide-doped rare earth tantalum niobate high-toughness ceramic powder as described in claim 2, characterized in that: In step (1), the rare earth oxide RE2O3 powder is any one or more of gadolinium oxide (Gd2O3), yttrium oxide (Y2O3), ytterbium oxide (Yb2O3), neodymium oxide (Nd2O3), samarium oxide (Sm2O3), europium oxide (Eu2O3), dysprosium oxide (Dy2O3), erbium oxide (Er2O3), and lutetium oxide (Lu2O3).

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