CN113354398B - Aluminum oxide-based high-entropy eutectic ceramic and preparation method thereof - Google Patents

Aluminum oxide-based high-entropy eutectic ceramic and preparation method thereof Download PDF

Info

Publication number
CN113354398B
CN113354398B CN202110774439.XA CN202110774439A CN113354398B CN 113354398 B CN113354398 B CN 113354398B CN 202110774439 A CN202110774439 A CN 202110774439A CN 113354398 B CN113354398 B CN 113354398B
Authority
CN
China
Prior art keywords
entropy
ball
eutectic
eutectic ceramic
milling
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CN202110774439.XA
Other languages
Chinese (zh)
Other versions
CN113354398A (en
Inventor
钟玉洁
王旭
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xian Shiyou University
Original Assignee
Xian Shiyou University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xian Shiyou University filed Critical Xian Shiyou University
Priority to CN202110774439.XA priority Critical patent/CN113354398B/en
Publication of CN113354398A publication Critical patent/CN113354398A/en
Application granted granted Critical
Publication of CN113354398B publication Critical patent/CN113354398B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
    • C04B2235/3222—Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
    • C04B2235/3225—Yttrium oxide or oxide-forming salts thereof
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
    • C04B2235/9607—Thermal properties, e.g. thermal expansion coefficient

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Compositions Of Oxide Ceramics (AREA)

Abstract

The invention discloses Al 2 O 3 Firstly, mixing mixed raw material powder and ball-milling solventMixing, performing ball milling, drying, pressing and sintering to obtain a prefabricated part; the mixed raw material powder is Al 2 O 3 、Y 2 O 3 、Er 2 O 3 、Yb 2 O 3 、Ho 2 O 3 And Lu 2 O 3 A mixture of (a); then the prefabricated part is directionally solidified in a light suspension zone melting furnace to obtain Al 2 O 3 High entropy eutectic ceramics. The novel high-entropy eutectic ceramic consists of low-entropy phase Al 2 O 3 And high entropy phase (Y) 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 And (4) forming. It shows obvious growth anisotropy, and the phase interface relationship between the low-entropy phase and the high-entropy phase has definite orientation. The eutectic ceramic has compact structure and excellent high-temperature performance, and can realize controllable structure size and performance modulation by modulating the solidification rate.

Description

Aluminum oxide-based high-entropy eutectic ceramic and preparation method thereof
Technical Field
The invention belongs to the technical field of eutectic ceramic preparation, and particularly relates to Al 2 O 3 High-entropy eutectic ceramic and Al thereof 2 O 3 A preparation method of high-entropy eutectic ceramic.
Background
Improving the efficiency of the gas turbine is an effective way to develop high-performance aircraft engines and is of great importance to the development of the aircraft industry. The higher the turbine inlet temperature of a gas turbine, the greater the turbine thermal efficiency. However, an increase in inlet temperature will result in its operating temperature approaching the temperature limit of the hot leg components. In particular, turbine blades made of nickel-base superalloys have a melting point of about 1300 c and cannot operate above 1150 c. Therefore, there is a need to develop a new generation of ultra-high temperature structural material capable of safely operating at high intake air temperatures for a long period of time.
In recent years, high-entropy ceramics have attracted extensive attention of researchers with their novel "high-entropy effect" and excellent properties. High entropy ceramics refer to multi-component solid solutions composed of five or more ceramic components. There are four effects of the high entropy ceramic structure formed during crystallization: high entropy effect, lattice distortion effect, slow diffusion effect, and cocktail effect. The mixing entropy of the alloy melt with the equal atomic ratio consisting of five elements can reach 1.61R, and the melting entropy of general metal alloys is about 1R. The high-entropy alloy has serious lattice distortion which inevitably affects the mechanical properties and the like of the material. The 'cocktail' effect of the high-entropy alloy means that the natural characteristics of various elements of the high-entropy alloy and the interaction between the elements cause the high-entropy alloy to present a complex effect. For example, if more light elements are used, the overall density of the alloy will decrease; if more antioxidant elements are used, such as aluminum or silicon, the high temperature oxidation resistance of the alloy is increased. Thus, in general, high entropy ceramics have better performance than traditional ceramics.
At present, the high-entropy ceramic is mainly prepared by a traditional hot-pressing sintering method. The traditional hot-pressing sintering technology is solid-solid conversion, the prepared high-entropy ceramic has the tissue defects of human phase interfaces, glass and the like, the porosity is slightly high, the density of the material is insufficient, the high-temperature tissue structure stability and controllability of the material are poor, and the high-temperature mechanical property is poor. Is not suitable for being used as an ultra-high temperature structural material.
In recent years, the directional solidification oxide eutectic in-situ composite material has attracted wide attention with unique tissue structure and excellent high-temperature mechanical property, the eutectic phase in the directional solidification oxide eutectic in-situ composite material is separated out from a melt to be in-situ compounded, the phase interface is combined with a specific crystallographic relation, the artificial interface in the traditional artificial composite material preparation process is abandoned, the interface amorphous phase in the powder sintering process is eliminated, and the high-temperature tissue structure stability and the high-temperature mechanical property of the material are improved; the oxide is melted into liquid, so that holes are reduced, and the density of the material is improved; the directional solidification eutectic in-situ composite material has obvious anisotropy, and excellent room temperature and high temperature mechanical performance especially in the preferred growth direction.
Disclosure of Invention
The invention aims to provide Al 2 O 3 High-entropy eutectic ceramic and Al prepared from same 2 O 3 Radical (Al) 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 ) The high-entropy eutectic ceramic has uniform structure and good mechanical property.
Another object of the present invention is to provide the above Al 2 O 3 The preparation method of the high-entropy eutectic ceramic improves the density and stability of the ceramic material.
The invention adopts the technical scheme that Al is 2 O 3 Based high-entropy eutectic ceramic composed of low-entropy phase Al 2 O 3 And high entropy phase Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 Two phases; the expression is Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 。
The other technical scheme adopted by the invention is that Al 2 O 3 The preparation method of the high-entropy eutectic ceramic is implemented according to the following steps:
step 1, mixing mixed raw material powder and a ball-milling solvent, and performing ball milling, drying, pressing and sintering in sequence to obtain a prefabricated member;
the mixed raw material powder is Al 2 O 3 、Y 2 O 3 、Er 2 O 3 、Yb 2 O 3 、Ho 2 O 3 And Lu 2 O 3 A mixture of (a);
step 2, directionally solidifying the prefabricated member in a light suspension zone melting furnace to obtain Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 High entropy eutectic ceramic.
The present invention is also characterized in that,
in step 1, the molar percentage of each raw material in the mixture is as follows, Al 2 O 3 ：Y 2 O 3 ＝79：21，Al 2 O 3 ：Er 2 O 3 ＝75：25，Al 2 O 3 ：Yb 2 O 3 ＝82：12，Al 2 O 3 ：Ho 2 O 3 ＝80.5：19.5，Al 2 O 3 ：Lu 2 O 3 ＝82：18。
In the step 1, the process of mixing the raw material powder and the ball-milling solvent and the process of ball-milling are carried out in a planetary ball mill, wherein the ball-milling solvent is ethanol; the ball milling time is 24 h; the rotating speed of ball milling is 400-700 r/min; the drying time is 24-48 h, and the drying temperature is 60-80 ℃.
In the step 1, pressing comprises sequentially performing dry pressing and cold isostatic pressing; the pressure of dry pressure is 20-30 MPa, and the pressure of cold isostatic pressing is 200-300 MPa; the sintering temperature is 1600 ℃ and the time is 2 h.
In the step 2, before directional solidification, the prefabricated part is subjected to rotary preheating, and the rotation rate of the rotary preheating is 15 r/min; the solidification rate of the directional solidification is 40-60 mm/h, and the temperature gradient is 10 3 K/cm。
The invention has the beneficial effects that: the invention adopts a directional solidification method to prepare Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 High entropy eutectic ceramics. The novel high-entropy eutectic ceramic consists of low-entropy phase Al 2 O 3 And high entropy phase (Y) 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 And (4) forming. It shows obvious growth anisotropy, and the phase interface relationship between the low-entropy phase and the high-entropy phase has definite orientation. With Al 2 O 3 Compared with eutectic ceramics with low entropy phase such as EAG, the fracture toughness and the Vickers hardness of the eutectic ceramics are respectively 6.8 +/-0.9 MPa-m 1/2 And 16.1 +/-0.3 GPa, are greatly improved. The thermal expansion coefficients are similar, but the thermal conductivity is as low as 4.9Wm due to strong lattice distortion -1 K -1 . The room-temperature bending strength is 333 +/-42 MPa. The main strengthening mechanisms are bridging, deflection and bifurcation of cracks. These results show that high entropy Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 Eutectic ceramics are a promising material for gas turbine structural members.
Drawings
FIG. 1 shows Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 And Al 2 O 3 /Er 3 Al 5 O 12 XRD pattern of eutectic ceramics;
FIG. 2 is Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 And Al 2 O 3 /Er 3 Al 5 O 12 An XRD (X-ray diffraction) pattern of the eutectic ceramic is amplified at about 53 degrees;
FIG. 3 is Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 SEM image of (a);
FIG. 4 is a distribution diagram of different elements of the corresponding region of FIG. 3;
FIG. 5 shows Al 2 O 3 /Er 3 Al 5 O 12 SEM picture of (1);
FIG. 6 is a distribution diagram of different elements of the corresponding region of FIG. 5;
FIG. 7a shows directionally solidified Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 EBSD map (one) of the eutectic ceramic;
FIG. 7b shows directionally solidified Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 EBSD map of eutectic ceramic (II);
FIG. 7c shows directionally solidified Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 Pole figure (one) of eutectic ceramic;
FIG. 7d shows directionally solidified Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 Pole figure (II) of eutectic ceramics;
FIG. 8a shows directionally solidified Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 A transmission electron micrograph of the eutectic ceramic cross section;
FIG. 8b shows the incident beam parallel to [1-100 ]]Al 2 O 3 And [011 ]](Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 HRTEM image at interface of two phases of crystal orientation;
FIG. 8c is Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 An electron diffraction pattern at the interface;
FIG. 9 is Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 Eutectic ceramics and other Al 2 O 3 A graph comparing values of fracture toughness and hardness of the base eutectic ceramic;
FIG. 10 shows Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 And Al 2 O 3 /Er 3 Al 5 O 12 A thermal expansion coefficient map of the eutectic ceramic;
FIG. 11 shows Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 ,Al 2 O 3 /Er 3 Al 5 O 12 ,Al 2 O 3 And Er 3 Al 5 O 12 Thermal conductivity map of (a).
Detailed Description
The invention is described in detail below with reference to the drawings and the detailed description.
Al of the invention 2 O 3 Based high-entropy eutectic ceramic composed of low-entropy phase Al 2 O 3 And high entropy phase RE 3 Al 5 O 12 (Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 ) Two phases; the expression is Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 (RE 3 Al 5 O 12 ) High entropy phase RE 3 Al 5 O 12 All RE atoms occupy the position of RE, and RE elements are uniformly distributed, and multi-component doping causes serious lattice distortion.
Al 2 O 3 Low entropy phase sum (Y) 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 The high entropy phase interlaces form a complex irregular staggered lamellar structure, which is a typical metal-free/metal-free eutectic structure, commonly referred to as a "cursive script". Compared with Al 2 O 3 The structure of the/EAG eutectic ceramic is finer, and the interface is smoother.
Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 The preferred orientation relation of the high-entropy eutectic ceramics is<10-10>{0001}Al 2 O 3 //<110>{211}(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 . This oriented crystallographic interface relationship is semi-coherent and has been shown to be the most interplanar spacing, the most densely arranged, and the lowest interfacial energy.
In directionally solidified oxide eutectic in autogenous composites, Al 2 O 3 The eutectic-based authigenic composite material has attracted attention due to its high melting point, high strength and good creep-resistant and oxidation-resistant properties, and is considered to be the most promising ultra-high temperature structural material. The most studied systems are: al (Al) 2 O 3 /Y 3 Al 5 O 12 (YAG),Al 2 O 3 /Er 3 Al 5 O 12 (EAG) and Al 2 O 3 /GdAlO 3 (GAP), etc. The invention adopts the directional solidification technology to prepare Al 2 O 3 The high-entropy ceramic is used for realizing the use of a high-performance ultrahigh-temperature structural part. The invention selects the combination of five elements of Y, Er, Yb, Ho and Lu, and adopts the directional solidification technology to prepare a new material, namely a dual-phase (low entropy phase/high entropy phase) Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 Eutectic ceramics. Al prepared by directional solidification technology 2 O 3 The high-entropy eutectic ceramic not only has compact structure and excellent high-temperature performance, but also can realize controllable structure size and performance modulation by modulating the solidification rate.
Selecting Al as raw material in the application 2 O 3 、Y 2 O 3 、Er 2 O 3 、Yb 2 O 3 、Ho 2 O 3 And Lu 2 O 3 ，Al 2 O 3 In the basic eutectic ceramics, Al 2 O 3 And Y 2 O 3 、Er 2 O 3 、Yb 2 O 3 、Ho 2 O 3 、Lu 2 O 3 The eutectic ceramics composed of the five rare earth oxides have good high-temperature mechanical property and thermal property. And Y is 2 O 3 、Er 2 O 3 、Yb 2 O 3 、Ho 2 O 3 、Lu 2 O 3 The five rare earth oxides are all in face-centered cubic structures. Can combine to form high-entropy phase to prepare Al 2 O 3 High entropy eutectic ceramics. And the high-entropy ceramic has a high-entropy effect, a lattice distortion effect, a slow diffusion effect and a cocktail effect. These four core effects give high entropy ceramics better performance than traditional ceramics.
Al of the invention 2 O 3 The preparation method of the high-entropy eutectic ceramic is implemented according to the following steps:
step 1, mixing mixed raw material powder and a ball-milling solvent, and performing ball milling, drying, pressing and sintering in sequence to obtain a prefabricated member;
the mixed raw material powder is Al 2 O 3 、Y 2 O 3 、Er 2 O 3 、Yb 2 O 3 、Ho 2 O 3 And Lu 2 O 3 The molar percentage of each raw material in the mixture is as follows, Al 2 O 3 ：Y 2 O 3 ＝79：21，Al 2 O 3 ：Er 2 O 3 ＝75：25，Al 2 O 3 ：Yb 2 O 3 ＝82：12，Al 2 O 3 ：Ho 2 O 3 ＝80.5：19.5，Al 2 O 3 ：Lu 2 O 3 ＝82：18；
Al 2 O 3 The purity of (b) is preferably 99.95%; y is 2 O 3 ,Er 2 O 3 ,Yb 2 O 3 ,Ho 2 O 3 And Lu 2 O 3 The purity of (b) is preferably 99.99%. In the present invention, the particle size of the raw material powder is preferably in the order of micrometers;
the process of mixing the raw material powder with the ball-milling solvent and the process of ball-milling are preferably carried out in a planetary ball mill, and in the present invention, the ball-milling solvent is ethanol; the ball milling time is 24 h; the rotating speed of the ball milling is preferably 400-700 r/min; the drying time is 24-48 h, and the drying temperature is 60-80 ℃.
Pressing comprises sequentially performing dry pressing and cold isostatic pressing; the pressure of dry pressure is 20-30 MPa, and the pressure of cold isostatic pressing is 200-300 MPa; the air in the sample is reduced by cold isostatic pressing, and the density is improved. Pressing to obtain a strip sample, wherein the size of the strip sample is 10mm multiplied by 100mm, so that the subsequent sintering is facilitated, the sintering temperature is 1600 ℃, and the time is 2 hours;
step 2, directionally solidifying the prefabricated member in a light suspension zone melting furnace to obtain Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 High-entropy eutectic ceramics;
before the directional solidification, the prefabricated part is subjected to rotary preheating, and the rotation speed of the rotary preheating is 15 r/min.
The solidification rate of the directional solidification is 40-60 mm/h, and the temperature gradient is 10 3 K/cm。
The method preferably comprises the steps of chamfering the prefabricated member, cutting out a suspended ditch and then performing the light suspension zone melting experiment process; the heat source of the optical suspension zone melting furnace is preferably a xenon lamp, the power of the xenon lamp is preferably 3kW, the number of the xenon lamps is preferably 4, and the xenon lamps are preferably arranged in the optical suspension zone melting furnace at equal intervals to ensure that the intervals of the xenon lamps in the heating area of the optical suspension zone melting furnace are equal. By controlling the heat source of the furnace in the light suspension zone under the above conditions, the solidification rate can be ensured to be within the range of 40-60 mm/h.
In the following examples, Al was used 2 O 3 Has a purity of 99.95% and a particle diameter of 2 to 10 μm, and Y is 2 O 3 ,Er 2 O 3 ,Yb 2 O 3 ，Ho 2 O 3 And Lu 2 O 3 The purity of the particles is 99.99%, and the particle size is 2-10 mu m; the heat source of the used light suspension zone melting furnace is a xenon lamp, the power of the xenon lamp is 3kW, the number of the xenon lamps is 4, and the xenon lamps are arranged in the light suspension zone melting furnace at equal intervals.
Example 1
Mixing Al 2 O 3 And Y 2 O 3 ,Er 2 O 3 ,Yb 2 O 3 ，Ho 2 O 3 ,Lu 2 O 3 Mixture of (mole percent Al) 2 O 3 :Y 2 O 3 ＝79:21,Al 2 O 3 :Er 2 O 3 ＝75:25,Al 2 O 3 :Yb 2 O 3 ＝82:12,Al 2 O 3 :Ho 2 O 3 ＝80.5:19.5,Al 2 O 3 :Lu 2 O 3 82:18) adding analytically pure ethanol, placing the mixture in a planetary ball mill, mixing for 36 hours (the ball milling speed is 400r/min), and placing the obtained mixed material in a drying oven to dry for 24 hours at 70 ℃;
pressing the dried powder for 35min under the pressure of 30MPa to obtain a sample with the size of 10mm multiplied by 100 mm; then carrying out cold isostatic pressing under the pressure of 280MPa, and fully loading for 50min to obtain a strip-shaped sample; then sintering the obtained strip sample in a sintering furnace at 1600 ℃ for 2h in an air atmosphere to obtain a prefabricated part;
placing the prefabricated member into a light suspension zone melting furnace, carrying out clockwise rotation preheating according to the speed of 15r/min until the prefabricated member is melted to form a liquid drop, enabling the liquid drop to be in contact with seed crystals to form a suspension zone, keeping the temperature for 1min, starting a drawing system, and keeping the temperature for 40mm/hDrawing rate (i.e., solidification rate) with a set temperature gradient of 10 3 K/cm, directional solidification is carried out to obtain Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 High entropy eutectic ceramics.
Example 2
This example differs from example 1 in that: the raw material mixture is Al 2 O 3 And Er 2 O 3 (mol% Al) 2 O 3 :Er 2 O 3 81:19) set temperature gradient of 10 3 K/cm, directional solidification is carried out to obtain Al 2 O 3 /Er 3 Al 5 O 12 Eutectic ceramics.
Tissue morphology characterization and performance testing
The texture structure of the eutectic ceramic sample rod prepared in the embodiment 1-2 is characterized, the mechanical property is tested, and the test method and the result are as follows.
1) Phase composition observation: the eutectic ceramic sample rods prepared in examples 1 to 2 were cut out by a diamond saw, and XRD tests were performed, and the results are shown in fig. 1 and 2. As can be seen from FIG. 1, Al 2 O 3 /Er 3 Al 5 O 12 Eutectic ceramic sample rod containing only Al 2 O 3 And Er 3 Al 5 O 12 Two phases. And Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 The high-entropy eutectic ceramic only contains Al 2 O 3 And RE 3 Al 5 O 12 Two phases. As can be seen from FIG. 2, RE 3 Al 5 O 12 Wherein all RE atoms occupy RE 3 Al 5 O 12 The RE position of the crystal structure. The doping of multiple components causes large lattice distortions.
2) And (3) observing the tissue morphology: the eutectic ceramic sample rods prepared in examples 1 to 2 were cut out by a diamond saw and analyzed by SEM test, and the results are shown in fig. 3 to 6. As can be seen from the figure, the constituent phases of the eutectic ceramics are intermingled with each other to form a complexThe irregular staggered lamellar structure is a typical metal-free/metal-free eutectic structure, and this morphology is commonly referred to as "cursive writing". Al (Al) 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 High entropy eutectic ceramic phase Al 2 O 3 /Er 3 Al 5 O 12 The eutectic ceramic has finer structure and the interface between two phases is relatively clearer and smoother. (Y) 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 In the high entropy phase, all RE elements are uniformly distributed.
3) And (3) observing a growth structure: the eutectic ceramic sample rods prepared in examples 1 to 2 were cut out by a diamond saw, and EBSD observation and TEM observation were performed, and the results are shown in fig. 7 and 8. Al can be obtained by analysis 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 The preferred orientation relation of the high-entropy eutectic ceramics is<10-10>{0001}Al 2 O 3 //<110>{211}(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 . The crystallographic interface relationship for this orientation is semi-coherent, with the largest interplanar spacing, the densest alignment, and the lowest interfacial energy.
4) Microhardness and fracture toughness testing: sample bars were cut with a diamond saw for Al prepared in example 1 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 The hardness, strength and toughness of the high-entropy eutectic ceramic test bars were measured and compared with the values of the prior art, and the results are shown in fig. 9. Vickers hardness was measured using a microscopic Vickers hardness tester (HVT-1000A, China). The experimental loads were 5, 10, 30 and 50N, and the time to full load was 15 s. The measured value was 16.1. + -. 0.3 GPa.
The bending strength of the test piece was measured by a three-point bending method, and the test piece had dimensions of 3mm × 4mm × 36 mm. The result was found to be 333. + -. 42 MPa.
In addition, the first and second substrates are,according to the fracture mechanics theory, the material near the indentation generates residual stress due to elastic-plastic deformation instability, and the residual stress field strength of the crack tip in the equilibrium state is numerically recorded as the fracture toughness K of the material IC The expression is as follows:
K IC ＝0.016×(E/H V ) 1/2 (p/c 3/2 )(1)
in the formula (1), E is the elastic modulus, HV is the Vickers hardness, p is the load, and c is the half crack length. Calculating Al according to the formula (1) 2 O 3 The fracture toughness of the/EAG eutectic ceramic is K IC ＝6.8±0.9MPa·m 1/2
As can be seen from FIG. 9, Al produced by the present invention 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 The fracture toughness value of the high-entropy eutectic ceramic is higher than that of Al reported in the prior art 2 O 3 Based on a binary eutectic ceramic.
5) Coefficient of thermal expansion and thermal conductivity measurements: the results of measuring the thermal expansion coefficient by an optical dilatometer (ODHT, Modena, Italy) over a temperature range of 100 ℃ to 1200 ℃ are shown in FIG. 10. The coefficient of thermal expansion increases exponentially from 100 ℃ to 500 ℃ and then slowly increases to approach a constant. Al (Al) 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 High entropy eutectic ceramic and Al 2 O 3 /Er 3 Al 5 O 12 The coefficients of thermal expansion of the eutectic ceramics are similar.
The thermal conductivity (κ) is deduced from the thermal diffusivity (α), density (ρ) and heat capacity (Cp) and the results are shown in fig. 11:
κ＝αCpρ (2)
Al 2 O 3 thermal conductivity order of the base ceramic: al (Al) 2 O 3 >Al 2 O 3 /Er 3 Al 5 O 12 >Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 >Er 3 Al 5 O 12 。

Claims (6)

1. Al (aluminum) 2 O 3 The high-entropy eutectic ceramic is characterized by comprising a low-entropy phase Al 2 O 3 And high entropy phase (Y) 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 Two phases; the expression is Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 。
2. Al 2 O 3 The preparation method of the high-entropy eutectic ceramic is characterized by comprising the following steps:
step 1, mixing mixed raw material powder and a ball-milling solvent, and performing ball milling, drying, pressing and sintering in sequence to obtain a prefabricated member;
the mixed raw material powder is Al 2 O 3 、Y 2 O 3 、Er 2 O 3 、Yb 2 O 3 、Ho 2 O 3 And Lu 2 O 3 A mixture of (a);
step 2, directionally solidifying the prefabricated member in a light suspension zone melting furnace to obtain Al 2 O 3 /(Y 0.2 Er 0.2 Yb 0.2 Ho 0.2 Lu 0.2 ) 3 Al 5 O 12 High entropy eutectic ceramics.
3. Al according to claim 2 2 O 3 The preparation method of the high-entropy eutectic ceramic is characterized in that in the step 1, the mol percentage of each raw material in the mixture is as follows, and Al 2 O 3 ：Y 2 O 3 ＝79：21，Al 2 O 3 ：Er 2 O 3 ＝75：25，Al 2 O 3 ：Yb 2 O 3 ＝82：12，Al 2 O 3 ：Ho 2 O 3 ＝80.5：19.5，Al 2 O 3 ：Lu 2 O 3 ＝82：18。
4. Al according to claim 2 2 O 3 The preparation method of the high-entropy eutectic ceramic is characterized in that in the step 1, a process of mixing raw material powder and a ball-milling solvent and a process of ball-milling are carried out in a planetary ball mill, wherein the ball-milling solvent is ethanol; the ball milling time is 24 h; the rotating speed of ball milling is 400-700 r/min; the drying time is 24-48 h, and the drying temperature is 60-80 ℃.
5. Al according to claim 2 2 O 3 The preparation method of the high-entropy eutectic ceramic is characterized in that in the step 1, pressing comprises sequentially performing dry pressing and cold isostatic pressing; the pressure of dry pressure is 20-30 MPa, and the pressure of cold isostatic pressing is 200-300 MPa; the sintering temperature is 1600 ℃ and the time is 2 h.
6. Al according to claim 2 2 O 3 The preparation method of the high-entropy eutectic ceramic is characterized in that in the step 2, the prefabricated part is subjected to rotary preheating before directional solidification, and the rotation rate of the rotary preheating is 15 r/min; the solidification rate of the directional solidification is 40-60 mm/h, and the temperature gradient is 10 3 K/cm。
CN202110774439.XA 2021-07-08 2021-07-08 Aluminum oxide-based high-entropy eutectic ceramic and preparation method thereof Expired - Fee Related CN113354398B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110774439.XA CN113354398B (en) 2021-07-08 2021-07-08 Aluminum oxide-based high-entropy eutectic ceramic and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110774439.XA CN113354398B (en) 2021-07-08 2021-07-08 Aluminum oxide-based high-entropy eutectic ceramic and preparation method thereof

Publications (2)

Publication Number Publication Date
CN113354398A CN113354398A (en) 2021-09-07
CN113354398B true CN113354398B (en) 2022-08-05

Family

ID=77538698

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110774439.XA Expired - Fee Related CN113354398B (en) 2021-07-08 2021-07-08 Aluminum oxide-based high-entropy eutectic ceramic and preparation method thereof

Country Status (1)

Country Link
CN (1) CN113354398B (en)

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4507394A (en) * 1982-12-24 1985-03-26 Ngk Insulators, Ltd. High electric resistant zirconia and/or hafnia ceramics
US5008221A (en) * 1985-04-11 1991-04-16 Corning Incorporated High toughness ceramic alloys
DE3856206T2 (en) * 1987-03-16 1999-03-11 Hitachi Ltd Sintered ceramic body and process for its manufacture
JP3852804B2 (en) * 1998-03-26 2006-12-06 独立行政法人科学技術振興機構 Method for producing oxide-based eutectic ceramic fiber
CN1907906A (en) * 2005-08-05 2007-02-07 李根法 Eutectic powder additive for producing ceram and ceramic solder and preparation method thereof
CN102020458B (en) * 2010-11-04 2013-05-08 西北工业大学 Method for getting structure appearance of aluminum oxide-based ternary melt growth ceramic
CN103304227B (en) * 2013-07-01 2014-08-13 沈阳铸造研究所 Alumina-based ceramic core for directional solidification and preparation method thereof
CN104193311B (en) * 2014-09-05 2016-02-24 哈尔滨工业大学 A kind of oxide eutectic pottery amorphous powder reactive spray preparation method
CN105314971B (en) * 2015-12-07 2019-01-08 哈尔滨工业大学 A kind of method that pulsed discharge plasma auxiliary remelting prepares the spontaneous composite ceramics of alumina base ternary eutectic
CN110526706B (en) * 2019-09-19 2021-09-21 安徽工业大学 Eutectic high-entropy oxide powder material and preparation method thereof
CN111056827B (en) * 2019-11-29 2021-09-24 中国科学院金属研究所 High-temperature phase-stable multi-component rare earth silicate solid solution ceramic and preparation method thereof
CN111235629B (en) * 2020-03-09 2021-04-23 西北工业大学深圳研究院 Preparation method of alumina-YAG eutectic melt growth composite material
CN112142467B (en) * 2020-09-25 2022-08-30 西安石油大学 Al (aluminum) 2 O 3 EAG eutectic ceramic and preparation method thereof
CN112830782B (en) * 2021-01-25 2021-10-26 山东大学 High-entropy rare earth niobium/tantalum/molybdate ceramic and preparation method thereof

Also Published As

Publication number Publication date
CN113354398A (en) 2021-09-07

Similar Documents

Publication Publication Date Title
Zhao et al. High-entropy (Y0. 2Nd0. 2Sm0. 2Eu0. 2Er0. 2) AlO3: A promising thermal/environmental barrier material for oxide/oxide composites
CN113023776B (en) Fluorite-structured high-entropy oxide powder for thermal barrier coating and preparation method thereof
JP7412019B2 (en) Rare earth tantalate ceramics that prevent corrosion due to low melting point oxides and their manufacturing method
Jiang et al. Effect of additives on properties of aluminium titanate ceramics
CN113045312B (en) High-entropy yttrium pyrochlore ceramic with glass-like thermal conductivity and preparation method thereof
CN114853477B (en) Ablation-resistant high-entropy carbide-high-entropy boride-silicon carbide composite ceramic and preparation method thereof
CN114436656B (en) High-entropy silicate ceramic with low thermal conductivity and high thermal stability, and preparation method and application thereof
CN113042753B (en) Method for reducing SLM forming nickel-based superalloy cracks and improving mechanical property
CN114478005B (en) Tetragonal phase thermal barrier coating material and preparation method thereof
CN110372386B (en) Method for preparing compact tantalum carbide ceramic through low-temperature liquid-phase hot-pressing sintering
Sun et al. Effect of heat treatment on microstructure and property of plasma-sprayed lanthanum hexaaluminate coating
Ye et al. Ultrafast high-temperature sintering of (Y0. 2Dy0. 2Er0. 2Tm0. 2Yb0. 2) 4Hf3O12 high-entropy ceramics with defective fluorite structure
Luo et al. Pressureless sintering of high performance silicon nitride ceramics at 1620° C
CN114956818A (en) Low-thermal-conductivity high-entropy cerate ceramic material and preparation method thereof
Chen et al. A high-entropy (Yb0. 2Y0. 2Lu0. 2Ho0. 2Er0. 2) 2Si2O7 environmental barrier coating prepared by atmospheric plasma-spray
Ye et al. Ultrafast high-temperature sintering of high-entropy (La0. 2Nd0. 2Sm0. 2Eu0. 2Gd0. 2) 2Hf2O7 ceramics with fluorite structure
Xu et al. In-situ preparation and thermal shock behavior of corundum–mullite–magnesium aluminate spinel composite ceramic
Mechnich et al. Accelerated reaction bonding of mullite
CN113354398B (en) Aluminum oxide-based high-entropy eutectic ceramic and preparation method thereof
Henniche et al. Microstructure and mechanical properties of ceramics obtained from chemically co-precipitated Al2O3-GdAlO3 nano-powders with eutectic composition
CN117383938A (en) High-entropy rare earth niobate ceramic coating material and preparation method thereof
Henniche et al. Microstructure, mechanical and thermo-physical properties of hot-pressed Al2O3-GdAlO3-ZrO2 ceramics with eutectic composition
Zhou et al. Nano-infiltration and transient eutectic (NITE) joining of SiC ceramics applied for the harsh environments
Chen et al. Oxidation of Ti 3 SiC 2 composites in air
Zhong et al. Microstructure of directionally solidified Al2O3/EAG eutectic ceramics prepared with high-temperature gradient

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20220805