A praseodymium-modified zirconium dioxide thermal barrier coating material and its preparation method

Abstract

This invention belongs to the field of thermal barrier coating technology for aero-engines, and relates to a praseodymium-modified zirconium dioxide thermal barrier coating material and its preparation method. The molecular formula of the praseodymium-modified zirconium dioxide thermal barrier coating material is Zr1-xPrxO2, where x = 0.1~0.3; the selected deposition process parameters are: vacuum degree of deposition chamber <5×10 ‑ 4 mbar; electron beam current intensity 1.6-2.0 A; sample temperature 1000-1050℃; evaporation time 50-80 min; controlling the evaporation time, a praseodymium-modified zirconia thermal barrier coating is finally obtained on a rotating sample. The thermal barrier coating material of this invention has a coefficient of thermal expansion close to that of YSZ and has a low thermal conductivity. Furthermore, the use of electron beam physical vapor deposition to prepare the praseodymium-modified zirconia thermal barrier coating results in a unique columnar crystal structure and good lifespan. This invention can reduce the thermal conductivity of the coating, increase its service temperature, and address the practical problems of insufficient service life and low coefficient of thermal expansion.

Description

Technical Field

[0001] This invention belongs to the field of thermal barrier coating technology for aero-engines, and relates to a praseodymium-modified zirconium dioxide thermal barrier coating material and its preparation method. Background Technology

[0002] Currently, with the continuous improvement of gas turbine thrust and efficiency, the gas inlet temperature is also increasing, and the operating temperature of nickel-based superalloys used in turbine blades and other hot-end components is gradually approaching their operating temperature limits. Thermal barrier coatings (TBCs) are a surface protection technology that utilizes the high-temperature resistance, erosion resistance, corrosion resistance, and low thermal conductivity of ceramic materials, combining them with a metal substrate in the form of a coating. This aims to increase the operating temperature of metal components, enhance the high-temperature resistance of hot-end components, extend the service life of hot-end components, and improve engine efficiency. Currently, the widely used YSZ (6-8 wt.% Y2O3 partially stabilized ZrO2) thermal barrier coating material has a long-term maximum operating temperature that cannot exceed 1200℃. During cooling, the volume expansion due to the monoclinic phase generated by phase transformation leads to coating failure. However, the long-term operating temperature of thermal barrier coating materials for next-generation high-performance aero-engines must exceed 1200℃. Therefore, researching new thermal barrier coating materials has become a key task in the development of next-generation high-performance aero-engines. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of the prior art by providing a praseodymium-modified zirconium dioxide thermal barrier coating material and its preparation method. The purpose is to solve the problems of insufficient service life of single zirconium dioxide thermal barrier coating and YSZ service temperature not exceeding 1200℃ by rare earth praseodymium doping modification, while also reducing the thermal conductivity of the material and increasing the coefficient of thermal expansion of the material.

[0004] To solve this technical problem, the technical solution of the present invention is as follows:

[0005] On one hand, a praseodymium-modified zirconium dioxide thermal barrier coating material is provided, wherein the molecular formula of the praseodymium-modified zirconium dioxide thermal barrier coating material is Zr. 1-x Pr x O2, where x = 0.1 to 0.3. Preferably, x = 0.15 to 0.22.

[0006] On the other hand, a method for preparing the praseodymium-modified zirconium dioxide thermal barrier coating is provided, comprising the following steps:

[0007] Step 1: Pr2O3 and ZrO2 are mixed according to the material molecular formula ratio, and praseodymium-modified zirconium dioxide target material is synthesized by high-temperature solid-state method at a synthesis temperature of 1800-2000℃.

[0008] Step 2: Prepare FeCrAlHfTa as the metal underlayer for thermal barrier coating using vacuum arc plating equipment, with a voltage of 600-650V and a current of 15-20A.

[0009] Step 3: The praseodymium-modified zirconium dioxide target is loaded into an electron beam physical vapor deposition apparatus. The praseodymium-modified zirconium dioxide target is evaporated by electron beam to prepare a praseodymium-modified zirconium dioxide thermal barrier coating on the FeCrAlHfTa substrate. The electron beam current intensity is 1.6-2.0A and the sample temperature is 1000-1050℃.

[0010] The purity of the raw materials Pr2O3 and ZrO2 in step one is ≥98%.

[0011] The raw material mixing in step one should be done by mechanical ball milling for a time of ≥24 hours.

[0012] The synthesis time for step one, the high-temperature solid-state method, is ≥24 hours.

[0013] In step two, the vacuum degree of the vacuum arc plating equipment is <1×10⁻⁶. -2 Pa.

[0014] In step two, the deposition time of the vacuum arc plating equipment is ≥100 min.

[0015] In step three, the vacuum level of the electron beam physical vapor deposition equipment is <5×10⁻⁶. -4 mbar.

[0016] In step three, the evaporation time for the electron beam physical vapor deposition thermal barrier coating is 50-80 minutes.

[0017] In step three, the thermal barrier coating deposited by electron beam physical vapor deposition is cooled to below 150°C in the furnace, and the cooling is natural cooling.

[0018] The advantages and beneficial effects of this invention are as follows:

[0019] This invention presents a novel type of thermal barrier coating material. Praseodymium-modified zirconia thermal barrier coatings exhibit high phase stability, showing no phase transformation after long-term heat treatment at 1200℃. Their coefficient of thermal expansion is close to that of YSZ, and they possess low thermal conductivity and good fracture toughness. Furthermore, the use of electron beam physical vapor deposition to prepare praseodymium-modified zirconia thermal barrier coatings results in a unique columnar crystal structure and excellent thermal cycling performance. Attached Figure Description

[0020] To more clearly illustrate the technical solutions implemented in this invention, the accompanying drawings used in the embodiments of this invention will be briefly explained below. Obviously, the drawings described below are merely some embodiments of this invention. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0021] Figure 1 These are schematic diagrams showing the thermal conductivity of Examples 1, 2, 3, and the comparative example.

[0022] Figure 2 Schematic diagrams of the thermal expansion coefficients of Examples 1, 2, 3, and the comparative example;

[0023] Figure 3 These are schematic diagrams illustrating the thermal life of Examples 1, 2, 3, and the comparative example.

[0024] Figure 4 This is a schematic diagram of the columnar crystal structure of the present invention;

[0025] Figure 5 A schematic diagram of thermal lifetimes with different Pr contents was prepared using the method in Example 2. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The features of various aspects of the embodiments of the present invention will now be described in detail. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can also be practiced without these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples. The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0028] The praseodymium-modified zirconium dioxide thermal barrier coating material of the present invention has the molecular formula Zr1-xPrxO2, wherein x = 0.1 to 0.3.

[0029] A method for preparing a praseodymium-modified zirconium dioxide thermal barrier coating material includes the following steps:

[0030] Raw materials Pr₂O₃ and ZrO₂ were mixed according to their molecular formula ratios, with a purity ≥98%. The mixing method was mechanical ball milling for ≥24 hours. Praseodymium-modified zirconium dioxide target material was synthesized via a high-temperature solid-state method at 1800-2000℃ for ≥24 hours. FeCrAlHfTa was prepared as the metal underlayer for the thermal barrier coating using vacuum arc plating equipment (the specific composition is consistent in the examples), with a vacuum degree <1×10⁻⁶. -2 The deposition time is ≥100 min, with a pressure of 600-650 V, a voltage of 600-650 V, a current of 15-20 A, and a deposition time of ≥100 min. The prepared target material is then loaded into an electron beam physical vapor deposition apparatus with a vacuum degree <5 × 10⁻⁶. -4 The thermal barrier coating was prepared by using mbar electron beam current intensity of 1.6-2.0A and evaporation time of 50-80min, and then naturally cooled to below 150℃ in the furnace.

[0031] Example 1:

[0032] (1) Raw material ratio: According to the chemical formula of praseodymium-modified zirconium dioxide thermal barrier coating material Zr0.9Pr0.1O2, weigh out the raw materials Pr2O3 and ZrO2.

[0033] (2) High-temperature solid-state synthesis: The raw materials were mechanically ball-milled for 30 hours, and praseodymium-modified zirconium dioxide target material was synthesized by high-temperature solid-state method at 1900℃ for 30 hours;

[0034] (3) Substrate preparation: FeCrAlHfTa was prepared as the metal substrate for the thermal barrier coating using vacuum arc plating equipment (the specific composition of the substrate is Fe20Cr20Al20Hf20Ta20), with a vacuum degree <1×10 -2 Pa, voltage 625V, current 18A, deposition time 150min;

[0035] (4) Thermal barrier coating preparation: Praseodymium-modified zirconium dioxide target material is loaded into an electron beam physical vapor deposition (EBPD) apparatus. Deposition process parameters: Vacuum degree <5×10⁻⁶ -4 mbar, electron beam intensity 1.7A, evaporation time 50min, after cooling to below 100 degrees Celsius, the deposition equipment was turned on to obtain praseodymium-modified zirconium dioxide thermal barrier coating.

[0036] Example 2:

[0037] (1) Raw material ratio: According to the chemical formula of praseodymium-modified zirconium dioxide thermal barrier coating material Zr0.85Pr0.15O2, weigh out the raw materials Pr2O3 and ZrO2.

[0038] (2) High-temperature solid-state synthesis: The raw materials were mechanically ball-milled for 36 hours, and praseodymium-modified zirconium dioxide target material was synthesized by high-temperature solid-state method at 1850℃ for 28 hours;

[0039] (3) Substrate preparation: FeCrAlHfTa was prepared as the metal substrate for the thermal barrier coating using a vacuum arc plating device with a vacuum degree <1×10⁻⁶. -2 Pa, voltage 645V, current 16A, deposition time 125min;

[0040] (4) Thermal barrier coating preparation: Praseodymium-modified zirconium dioxide target material is loaded into an electron beam physical vapor deposition (EBPD) apparatus. Deposition process parameters: Vacuum degree <5×10⁻⁶ -4 mbar, electron beam intensity 1.8A, evaporation time 60min, after cooling to below 100 degrees Celsius, the deposition equipment was turned on to obtain praseodymium-modified zirconium dioxide thermal barrier coating.

[0041] Example 3:

[0042] (1) Raw material ratio: According to the chemical formula of praseodymium-modified zirconium dioxide thermal barrier coating material, Zr0.75Pr0.25O2, weigh out the raw materials Pr2O3 and ZrO2.

[0043] (2) High-temperature solid-state synthesis: The raw materials were mechanically ball-milled for 36 hours, and praseodymium-modified zirconium dioxide target material was synthesized by high-temperature solid-state method at 1900℃ for 30 hours;

[0044] (3) Substrate preparation: FeCrAlHfTa was prepared as the metal substrate for the thermal barrier coating using a vacuum arc plating device with a vacuum degree <1×10⁻⁶. -2 Pa, voltage 650V, current 18A, deposition time 120min;

[0045] (4) Thermal barrier coating preparation: Praseodymium-modified zirconium dioxide target material is loaded into an electron beam physical vapor deposition (EBPD) apparatus. Deposition process parameters: Vacuum degree <5×10⁻⁶ -4 mbar, electron beam intensity 1.9A, evaporation time 60min, after cooling to below 100 degrees Celsius, the deposition equipment was turned on to obtain praseodymium-modified zirconium dioxide thermal barrier coating.

[0046] Comparative example:

[0047] (1) Raw material ratio: According to the chemical formula of praseodymium-modified zirconium dioxide thermal barrier coating material Zr0.5Pr0.5O2, weigh out the raw materials Pr2O3 and ZrO2.

[0048] (2) High-temperature solid-state synthesis: The raw materials were mechanically ball-milled for 12 hours, and praseodymium-modified zirconium dioxide target material was synthesized by high-temperature solid-state method at 2000℃ for 12 hours;

[0049] (3) Substrate preparation: FeCrAlHfTa was prepared as the metal substrate for the thermal barrier coating using vacuum arc plating equipment (the specific composition of the substrate is Fe20Cr20Al20Hf20Ta20), with a vacuum degree <1×10 -2 Pa, voltage 700V, current 10A, deposition time 100min;

[0050] (4) Thermal barrier coating preparation: Praseodymium-modified zirconium dioxide target material is loaded into an electron beam physical vapor deposition (EBPD) apparatus. Deposition process parameters: Vacuum degree <5×10⁻⁶ -4 mbar, electron beam intensity 1.4A, evaporation time 40min, after cooling to below 100 degrees Celsius, the deposition equipment was turned on to obtain praseodymium-modified zirconium dioxide thermal barrier coating.

[0051] As can be seen from the above embodiments:

[0052] (1) Using electron beam physical vapor deposition technology to prepare thermal barrier coatings will give thermal barrier coatings a unique columnar crystal structure and good thermal cycling performance.

[0053] (2) In terms of coating design, a uniform coating structure is obtained by modifying the rare earth praseodymium. This invention can reduce the thermal conductivity of the zirconium dioxide coating and improve the actual problem of insufficient service life of single zirconium dioxide.

[0054] from Figure 1-3 It can be seen that the thermal conductivity and coefficient of thermal expansion of praseodymium-modified zirconium dioxide coating materials decrease with increasing Pr doping. However, the key performance characteristic of thermal barrier coatings is thermal lifetime, which is comparable to... Figure 3 As shown, Example 2 exhibits the best thermal lifetime, reaching 700 hours, which is greater than that of YSZ. However, the performance of parameters and material compositions other than those in this invention differs significantly from that of Example 2. Therefore, the parameter combination of this invention (electron beam current intensity 1.6-2.0 A, sample temperature 1000-1050 °C) can maximize the improvement of thermal lifetime performance while meeting other performance requirements.

[0055] In addition, such as Figure 5 As shown, regarding the material composition (Zr) 1-x Pr x By varying the Pr content (where x = 0.1 to 0.3) using the same parameters as in Example 2, we found that different Pr atomic ratios resulted in different thermal lifetime performances. We observed that the coating exhibited the best thermal lifetime performance when x = 0.15 to 0.22.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a praseodymium-modified zirconium dioxide thermal barrier coating material, characterized in that: The molecular formula of the praseodymium-modified zirconium dioxide thermal barrier coating material is Zr. 1-x Pr x O2, where x = 0.15~0.22; The preparation method includes the following steps: Step 1: Pr2O3 and ZrO2 are mixed according to the material molecular formula ratio, and praseodymium-modified zirconium dioxide target material is synthesized by high temperature solid-state method at 1800-2000℃. Step 2: Prepare FeCrAlHfTa as the metal underlayer for thermal barrier coating using vacuum arc plating equipment, with a voltage of 600-650V and a current of 15-20A. Step 3: The praseodymium-modified zirconium dioxide target is loaded into an electron beam physical vapor deposition apparatus. The praseodymium-modified zirconium dioxide target is evaporated by electron beam to prepare a praseodymium-modified zirconium dioxide thermal barrier coating on the FeCrAlHfTa substrate. The electron beam current intensity is 1.6-2.0A and the sample temperature is 1000-1050℃.

2. The preparation method according to claim 1, characterized in that: The purity of the raw materials Pr2O3 and ZrO2 in step one is ≥98%.

3. The preparation method according to claim 1, characterized in that: The raw material mixing in step one should be done by mechanical ball milling for a time of ≥24 hours.

4. The preparation method according to claim 1, characterized in that: The synthesis time for step one, the high-temperature solid-state method, is ≥24 hours.

5. The preparation method according to claim 1, characterized in that: In step two, the vacuum degree of the vacuum arc plating equipment is <1×10⁻⁶. -2 Pa.

6. The preparation method according to claim 1, characterized in that: In step two, the deposition time of the vacuum arc plating equipment is ≥100 min.

7. The preparation method according to claim 1, characterized in that: In step three, the vacuum level of the electron beam physical vapor deposition equipment is <5×10⁻⁶. -4 mbar.

8. The preparation method according to claim 1, characterized in that: In step three, the evaporation time for the electron beam physical vapor deposition thermal barrier coating is 50-80 minutes.

9. The preparation method according to claim 1, characterized in that: In step three, the thermal barrier coating deposited by electron beam physical vapor deposition is cooled to below 150°C in the furnace, and the cooling is natural cooling.

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