阅读说明：本技术 一种二硼化铪-二硅化钽复合粉体及其制备方法 (Hafnium diboride-tantalum disilicide composite powder and preparation method thereof ) 是由 柳彦博 谢明劭 刘少璞 王一帆 于 2021-11-08 设计创作，主要内容包括：本发明提供了一种二硼化铪-二硅化钽复合粉体及其制备方法,属于复合粉体材料技术领域。本发明提供的二硼化铪-二硅化钽复合粉体为熔融共晶态,成分包括二硼化铪与二硅化钽,所述二硼化铪与二硅化钽的质量比为2～11:1。本发明使用二硅化钽作为二硼化铪的改性成分,一方面,二硅化钽的高温氧化产物SiO-(2)能够作为很好高温封填相,对二硼化铪涂层的孔洞缺陷进行封填；另一方面,二硅化钽的另一高温氧化产物Ta-(2)O-(5)能够与HfO-(2)发生固溶反应形成HfTaO-(x),一定程度抑制了HfO-(2)的晶型转变,提升了该粉体的高温热稳定性。因此,本发明提供的二硼化铪-二硅化钽复合粉体具有良好的高温抗氧化烧蚀特性。(The invention provides hafnium diboride-tantalum disilicide composite powder and a preparation method thereof, belonging to the technical field of composite powder materials. The hafnium diboride-tantalum disilicide composite powder provided by the invention is a molten eutectic state, and comprises the components of hafnium diboride and tantalum disilicide, wherein the mass ratio of the hafnium diboride to the tantalum disilicide is 2-11: 1. The invention uses tantalum disilicide as a modifying component of hafnium diboride, on the one hand, the high temperature oxidation product SiO of tantalum disilicide 2 Can be used as a good high-temperature sealing phase to seal and fill the hole defects of the hafnium diboride coating; on the other hand, Ta, another high-temperature oxidation product of tantalum disilicide 2 O 5 Can be reacted with HfO 2 Solid solution reaction occurs to form HfTaO x To a certain extent suppress HfO 2 The crystal form of the powder is changed, and the high-temperature thermal stability of the powder is improved. Therefore, the hafnium diboride-tantalum disilicide composite powder provided by the invention has good high-temperature oxidation resistanceAblation properties are normalized.)

1. The hafnium diboride-tantalum disilicide composite powder is a molten eutectic state, and comprises the components of hafnium diboride and tantalum disilicide, wherein the mass ratio of the hafnium diboride to the tantalum disilicide is 2-11: 1.

2. The hafnium diboride-tantalum disilicide composite powder of claim 1, wherein the particle size of the hafnium diboride-tantalum disilicide composite powder is 10 to 80 μm.

3. The hafnium diboride-tantalum disilicide composite powder according to claim 1 or 2, wherein the flowability of the hafnium diboride-tantalum disilicide composite powder is 9.88 to 11.25s/50g, and the bulk density is 6.19 to 6.38g/cm³。

4. The method for preparing the hafnium diboride-tantalum disilicide composite powder according to any one of claims 1 to 3, comprising the following steps:

(1) mixing hafnium diboride powder, tantalum disilicide powder, a binder and a polar dispersion solvent to obtain a precursor powder dispersion liquid, wherein the mass ratio of the hafnium diboride powder to the tantalum disilicide powder is 2-11: 1;

(2) and sequentially carrying out granulation, spheroidization and ultrasonic treatment on the precursor powder dispersion liquid to obtain the hafnium diboride-tantalum disilicide composite powder.

5. The preparation method according to claim 4, wherein the particle size of the hafnium diboride powder is 1-3 μm; the particle size of the tantalum disilicide powder is 1-3 microns.

6. The preparation method according to claim 4, wherein the binder is polyvinyl alcohol, the alcoholysis degree of the polyvinyl alcohol is not less than 88%, and the viscosity of the polyvinyl alcohol is 8-10 mPa-s.

7. The preparation method according to claim 4 or 6, wherein the mass percentage of the hafnium diboride powder and the tantalum disilicide powder in the precursor powder dispersion liquid in the step (1) is 35-60%, and the mass percentage of the binder is 0.4-0.6%.

8. The method according to claim 4, wherein the granulation is spray-dried granulation, and the parameters of the spray-dried granulation include:

the inlet temperature is 230-260 ℃;

the outlet temperature is 120-140 ℃;

the rotating speed of the spray head is 30-40 Hz;

the rotating speed of a peristaltic pump used for spray drying is 30-35 rpm.

9. The method according to claim 4, wherein the spheroidization process is an induction plasma spheroidization process, and the parameters of the induction plasma spheroidization process comprise:

the power was 40kW, the argon flow rate was 60SCFH, the hydrogen flow rate was 6SCFH, and the powder feed rate was 5.0 RPM.

10. The hafnium diboride-tantalum disilicide composite powder prepared by the method of any one of claims 1 to 3 or the hafnium diboride-tantalum disilicide composite powder prepared by the method of any one of claims 4 to 9 is used as an anti-oxidation ablation coating material.

Technical Field

The invention relates to the technical field of composite powder materials, in particular to hafnium diboride-tantalum disilicide composite powder and a preparation method thereof.

Background

Carbon fiber reinforced carbon matrix composites (C/C) are characterized by low density, low coefficient of thermal expansion at high temperatures, and excellent mechanical properties, and are considered to be one of the most promising materials for aircraft hot-end components. However, in an aerobic environment of 400 ℃ or higher, the carbon fiber reinforced carbon matrix composite is easily oxidized, resulting in a decrease in performance. Preparing an anti-oxidative ablative coating on the surface thereof is one of the effective methods.

Hafnium diboride (HfB)₂) The compound is a hexagonal metalloid structure compound, has the advantages of high melting point (3380 ℃) and hardness, excellent chemical stability and the like, and is expected to be used as an anti-oxidation ablation coating material of a carbon fiber reinforced carbon matrix composite material. At present, single hafnium diboride as an antioxidant material can generate a glass phase B under the high temperature condition of more than 1100 DEG C₂O₃Large amount of volatilization and HfO₂The oxide porous skeleton is exposed, so that the oxidation resistance is greatly reduced.

Disclosure of Invention

In view of the above, the present invention is directed to a hafnium diboride-tantalum disilicide composite powder and a preparation method thereof. The hafnium diboride-tantalum disilicide composite powder provided by the invention has good high-temperature oxidation resistance.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides hafnium diboride-tantalum disilicide composite powder which is in a molten eutectic state, and comprises the components of hafnium diboride and tantalum disilicide, wherein the mass ratio of the hafnium diboride to the tantalum disilicide is 2-11: 1.

Preferably, the particle size of the hafnium diboride-tantalum disilicide composite powder is 10-80 μm.

Preferably, the fluidity of the hafnium diboride-tantalum disilicide composite powder is 9.88 to 11.25s/50g, and the apparent density is 6.19 to 6.38g/cm³。

The invention provides a preparation method of the hafnium diboride-tantalum disilicide composite powder, which comprises the following steps:

(1) mixing hafnium diboride powder, tantalum disilicide powder, a binder and a polar dispersion solvent to obtain a precursor powder dispersion liquid, wherein the mass ratio of the hafnium diboride powder to the tantalum disilicide powder is 2-11: 1;

(2) and sequentially carrying out granulation, spheroidization and ultrasonic treatment on the precursor powder dispersion liquid to obtain the hafnium diboride-tantalum disilicide composite powder.

Preferably, the particle size of the hafnium diboride powder is 1-3 μm; the particle size of the tantalum disilicide powder is 1-3 microns.

Preferably, the binder is polyvinyl alcohol, the alcoholysis degree of the polyvinyl alcohol is more than or equal to 88%, and the viscosity of the polyvinyl alcohol is 8-10 mPa & s.

Preferably, the mass percentage of the hafnium diboride powder and the tantalum disilicide powder in the precursor powder dispersion liquid in the step (1) is 35-60%, and the mass percentage of the binder is 0.4-0.6%.

Preferably, the granulation is spray-drying granulation, and the parameters of the spray-drying granulation include:

the inlet temperature is 230-260 ℃;

the outlet temperature is 120-140 ℃;

the rotating speed of the spray head is 30-40 Hz;

the rotating speed of a peristaltic pump used for spray drying is 30-35 rpm.

Preferably, the spheroidizing process is an induction plasma spheroidizing process, and the parameters of the induction plasma spheroidizing process include:

the power was 40kW, the argon flow rate was 60SCFH, the hydrogen flow rate was 6SCFH, and the powder feed rate was 5.0 RPM.

The invention provides application of the hafnium diboride-tantalum disilicide composite powder as an anti-oxidation ablation coating material.

The invention provides hafnium diboride-tantalum disilicide composite powder which is in a molten eutectic state, and comprises the components of hafnium diboride and tantalum disilicide, wherein the mass ratio of the hafnium diboride to the tantalum disilicide is 2-11: 1. The invention uses tantalum disilicide as a modified component of hafnium diboride, and in a high-temperature environment, on the one hand, the high-temperature oxidation product SiO of the tantalum disilicide₂Can be used as a good high-temperature sealing phase to seal and fill the hole defects of the hafnium diboride coating; on the other hand, Ta, another high-temperature oxidation product of tantalum disilicide₂O₅Can be reacted with HfO₂Solid solution reaction occurs to form HfTaO_xTo a certain extent suppress HfO₂The crystal form of the powder is changed, and the high-temperature thermal stability of the powder is improved. Therefore, the hafnium diboride-tantalum disilicide composite powder provided by the invention has good high-temperature oxidation and ablation resistance, and the prepared hafnium diboride-tantalum disilicide composite coating can protect a substrate from being oxidized at 1800 ℃. The results of the examples show that the quality loss rate of the coating after the hafnium diboride-tantalum disilicide composite coating is evaluated by oxyacetylene ablation is 3.57 multiplied by 10^-4g/s, 10 lower than that of conventional ultrahigh temperature ceramic coating^-3Of this order.

Meanwhile, the hafnium diboride-tantalum disilicide composite powder provided by the invention has good powder flowability and apparent density, and is beneficial to preparation of coatings.

The invention provides a preparation method of the hafnium diboride-tantalum disilicide composite powder, and the preparation method adopts a method of mixing the hafnium diboride powder, the tantalum disilicide powder, the binder and the polar dispersing solvent, and sequentially carrying out granulation and spheroidization treatment, so that the preparation method is simple to operate, easy to realize industrial batch production and has good application prospect.

Drawings

FIG. 1 is a scanning electron microscope image of the surface of the hafnium diboride-tantalum disilicide composite powder obtained in example 1;

FIG. 2 is a cross-sectional scanning electron microscope image of the hafnium diboride-tantalum disilicide composite powder obtained in example 1;

FIG. 3 is an X-ray diffraction pattern of the hafnium diboride-tantalum disilicide composite powder obtained in example 1;

FIG. 4 is an elemental analysis chart of the hafnium diboride-tantalum disilicide composite powder prepared in example 1;

FIG. 5 is a scanning electron microscope image of a cross-section of a coating formed by hot pressing the hafnium diboride-tantalum disilicide composite powder of example 1.

Detailed Description

The invention provides hafnium diboride-tantalum disilicide composite powder which is a molten eutectic state, and comprises the following components in percentage by mass, wherein the mass ratio of the hafnium diboride to the tantalum disilicide is 2-11: 1, preferably 4-10: 1, and more preferably 6-8: 1. in the present invention, the volume ratio of the hafnium diboride to the tantalum disilicide is 2.3 to 9:1, preferably 4:1, in terms of volume ratio.

In the invention, the particle size of the hafnium diboride-tantalum disilicide composite powder is preferably 10-80 μm, more preferably 20-60 μm, and even more preferably 30-50 μm.

In the invention, the fluidity of the hafnium diboride-tantalum disilicide composite powder is preferably 9.88-11.25 s/50g, and more preferably 10.67s/50 g; the preferred loose density is 6.19-6.38 g/cm³More preferably 6.23g/cm³。

The invention uses tantalum disilicide as a modifying component of hafnium diboride, on the one hand, the oxidation product SiO of tantalum disilicide₂Can be used as a good high-temperature sealing phase to seal and fill the hole defects of the hafnium diboride coating; on the other hand, Ta, another oxidation product of tantalum disilicide₂O₅Can be reacted with HfO₂Solid solution reaction occurs to form HfTaO_xTo a certain extent suppress HfO₂The crystal form of the powder is changed, and the high-temperature thermal stability of the powder is improved.

The invention provides a preparation method of the hafnium diboride-tantalum disilicide composite powder, which comprises the following steps:

(1) mixing hafnium diboride powder, tantalum disilicide powder, a binder and a polar dispersion solvent to obtain a precursor powder dispersion liquid, wherein the mass ratio of the hafnium diboride powder to the tantalum disilicide powder is 2-11: 1;

(2) and sequentially carrying out granulation, spheroidization and ultrasonic treatment on the precursor powder dispersion liquid to obtain the hafnium diboride-tantalum disilicide composite powder.

The method comprises the steps of mixing hafnium diboride powder, tantalum disilicide powder, a binder and a polar dispersion solvent to obtain a precursor powder dispersion liquid, wherein the mass ratio of the hafnium diboride powder to the tantalum disilicide powder is 2-11: 1. In the invention, the particle size of the hafnium diboride powder is preferably 1-3 μm, and more preferably 2 μm; the purity of the hafnium diboride powder is preferably more than or equal to 99.9 percent.

In the invention, the particle size of the tantalum disilicide powder is preferably 1-3 μm, and more preferably 2 μm; the purity of the tantalum disilicide powder is preferably more than or equal to 99.9%.

In the invention, the binder is preferably polyvinyl alcohol, and the alcoholysis degree of the polyvinyl alcohol is preferably more than or equal to 88%, and more preferably 88-95%; the viscosity is preferably 8 to 10 mPas, and more preferably 9 mPas. In the present invention, the binder is used for binding the raw material particles.

In the present invention, the polar dispersion solvent is preferably water or absolute ethanol.

In the invention, the mass percentage content of the hafnium diboride powder and the tantalum disilicide powder in the precursor powder dispersion liquid is preferably 35-60%, and more preferably 40-50%; the mass percentage content of the binder is preferably 0.4-0.6%, and more preferably 0.5%.

The invention has no special requirements on the sources of the hafnium diboride powder, the tantalum disilicide powder, the binder and the polar dispersing solvent, and the products which are generally sold on the market in the field can be used.

In the present invention, the mixing is preferably performed by ball milling. In the invention, the rotation speed of the ball milling mixing is preferably 200-250 rpm, more preferably 220-240 rpm; the time is preferably not less than 3 hours, and more preferably 4 to 5 hours. In the invention, the ball-to-material ratio of the ball-milling mixing is preferably 3-5: 1, and more preferably 4: 1.

After the dispersion liquid is obtained, the precursor powder dispersion liquid is subjected to granulation, spheroidization and ultrasonic treatment in sequence to obtain the hafnium diboride-tantalum disilicide composite powder. In the present invention, the granulation is preferably spray-dried granulation. In the present invention, the granulation is preferably performed in a spray drying granulation tower. In the present invention, the parameters of the spray drying granulation preferably include:

the inlet temperature is preferably 230-260 ℃, and more preferably 250 ℃;

the outlet temperature is preferably 120-140 ℃, and more preferably 130 ℃;

the rotating speed of the spray head is preferably 30-40 Hz, and more preferably 35 Hz;

the rotating speed of a peristaltic pump used for spray drying is preferably 30-35 rpm, and more preferably 32 rpm.

And after granulation, obtaining the hafnium diboride-tantalum disilicide agglomerated powder, wherein the grain size of the hafnium diboride-tantalum disilicide agglomerated powder is preferably less than or equal to 105 microns, and more preferably 20-80 microns.

The invention preferably dries the hafnium diboride-tantalum disilicide agglomerated powder obtained after granulation. The invention has no special requirements on the specific operation mode of the drying, and the drying mode which is well known by the technicians in the field can be used.

In the present invention, the spheroidizing treatment is preferably an induction plasma spheroidizing treatment. The present invention preferably performs the induction plasma spheroidizing process in an induction plasma spheroidizing apparatus. In the present invention, the parameters of the induction plasma spheroidizing process preferably include: the power was 40kW, the argon flow rate was 60SCFH, the hydrogen flow rate was 6SCFH, and the powder feed rate was 5.0 RPM.

In the invention, the powder obtained after spheroidizing treatment is preferably dispersed in water for ultrasonic treatment. In the invention, the power of the ultrasonic wave is preferably 300-500W, and the time is preferably 20 min.

After the ultrasonic treatment, the solid-liquid separation is preferably carried out on the dispersion liquid after the ultrasonic treatment, the obtained powder is sequentially dried and sieved, and the hafnium diboride-tantalum disilicide composite powder is obtained, wherein the particle size of the hafnium diboride-tantalum disilicide composite powder is preferably 10-80 microns, more preferably 20-60 microns, and further preferably 30-50 microns.

After sieving, the obtained hafnium diboride-tantalum disilicide composite powder is preferably dried at the temperature of 80-200 ℃, more preferably 100-150 ℃; the time is preferably 20-30 h, and more preferably 25 h.

The invention provides application of the hafnium diboride-tantalum disilicide composite powder as an anti-oxidation ablation coating material.

The hafnium diboride-tantalum disilicide composite powder and the preparation method thereof provided by the present invention are described in detail below with reference to the examples, but they should not be construed as limiting the scope of the present invention.

In the following examples:

PVA: the purity is more than or equal to 97 percent and is produced by Beijing Yili fine chemicals GmbH.

Hafnium diboride and tantalum disilicide as raw materials: the particle size is 1-3 μm, the purity is 99.9%, and the product is purchased from Jinyan New Material science and technology Co., Ltd.

Spray drying prilling tower: LGZ-8 centrifugal spray dryer of Wuxi Dongjiang spray granulation drying machinery factory.

Induction plasma spheroidization equipment: induction plasma spheroidizing equipment manufactured by teknaplasmassysinc.

And (4) SEM characterization: the morphology of the hafnium diboride-tantalum disilicide composite powder prepared in the examples and the morphology of the prepared coating are observed by using a cold field emission scanning electron microscope model S-4800 of Japan high and new technology Co.

XRD analysis: the composite powder prepared in the embodiment is analyzed by an X' PertPRODPD type polycrystalline X-ray diffraction analyzer produced by PANALYtical corporation in the Netherlands; and (3) testing conditions are as follows: k of Cu_αThe beam, Ni filter, tube voltage 40kV, tube current 40mA, slit size DS 0.957 °, PSD 2.12, and scanning speed 4 °/min.

And (3) testing the fluidity: the fluidity of the prepared composite powder was measured by using a Hall flow meter model FL4-1 manufactured by Beijing institute of iron and Steel.

Loose density test: the test was carried out according to the measurement of the loose packed density of GBT 1479.1-2011 metal powder.

Oxygen-acetylene flame assessment: according to the GJB 323-.

Example 1

(1) Adding 739.9g of hafnium diboride, 260.1g of tantalum disilicide, 5g of PVA and 1500g of deionized water into a ball milling tank, wherein the ball-to-material ratio is 4:1, and carrying out ball milling for 3h at 250r/min to uniformly mix the components to obtain a suspension of precursor powder;

(2) transferring the suspension obtained in the step (1) to a spray drying granulation tower for agglomeration granulation, putting the granulated powder into an oven at 80 ℃ for drying for 30h, and then performing inspection screening to obtain HfB with the particle size of less than 105 mu m₂-TaSi₂Agglomerated powder (HfB)₂With TaSi₂The volume ratio is 7: 3);

wherein, the spray drying granulation parameters are as follows: the inlet temperature is 250 ℃, the outlet temperature is 130 ℃, the rotating speed of the spray head is 35Hz, and the rotating speed of the peristaltic pump is 30 rpm;

(3) to HfB₂-TaSi₂Sending the agglomerated powder into an induction plasma spheroidizing device for spheroidizing, collecting the spheroidized powder, pouring the collected powder into deionized water, carrying out ultrasonic treatment for 20min, finally pouring out turbid liquid, only reserving bottom sediments, placing the turbid liquid in a drying oven at 100 ℃ for drying for 30h, and then passing through a test sieve to obtain hafnium diboride-tantalum disilicide composite powder;

wherein, the induction plasma spheroidization parameters are as follows: the power is 40kW, the argon flow is 60SCFH, the hydrogen flow is 6SCFH, and the powder feeding rate is 5.0 RPM.

The surface Scanning Electron Microscope (SEM) of the obtained hafnium diboride-tantalum disilicide composite powder is shown in figure 1. As can be seen from FIG. 1, the obtained hafnium diboride-tantalum disilicide composite powder has a spherical shape with a compact and smooth surface and a particle size of 40 μm.

The cross-sectional Scanning Electron Microscope (SEM) of the obtained hafnium diboride-tantalum disilicide composite powder is shown in FIG. 2. As can be seen from FIG. 2, the cross section of the prepared composite powder has no obvious defect holes, and the modified additive tantalum disilicide and the hafnium diboride body are well combined.

The X-ray diffraction spectrum of the obtained hafnium diboride-tantalum disilicide composite powder is shown in figure 3. As can be seen from FIG. 3, characteristic peaks of hafnium diboride and tantalum disilicide appear in the spectrum; it is understood from this that tantalum disilicide was successfully added to the composite powder, and the composition was not changed during the preparation.

The element distribution of the obtained hafnium diboride-tantalum disilicide composite powder cross section is detected, and the obtained result is shown in figure 4. As can be seen from FIG. 4, the composite powder has no obvious segregation phenomenon of elements and the whole elements are uniformly distributed.

Example 2

(1) Adding 830.2g of hafnium diboride, 169.8g of tantalum disilicide, 5g of PVA and 1500g of deionized water into a ball milling tank, wherein the ball-to-material ratio is 4:1, and carrying out ball milling for 2 hours at 400r/min to uniformly mix the components to obtain a suspension of precursor powder;

(2) transferring the suspension obtained in the step (1) to a spray drying granulation tower for agglomeration granulation, putting the granulated powder into a drying oven at 150 ℃ for drying for 20h, and then performing inspection screening to obtain HfB with the particle size of less than 105 mu m₂-TaSi₂Agglomerated powder (HfB)₂With TaSi₂The volume ratio is 8: 2);

wherein, the spray drying granulation parameters are as follows: the inlet temperature is 250 ℃, the outlet temperature is 130 ℃, the rotating speed of the spray head is 35Hz, and the rotating speed of the peristaltic pump is 35 rpm;

(3) to HfB₂-TaSi₂Sending the agglomerated powder into an induction plasma spheroidizing device for spheroidizing, collecting the spheroidized powder, pouring the collected powder into deionized water, carrying out ultrasonic treatment for 20min, finally pouring out turbid liquid, only reserving bottom sediments, placing the turbid liquid in a drying oven at 100 ℃ for drying for 30h, and then passing through a test sieve to obtain hafnium diboride-tantalum disilicide composite powder;

wherein, the induction plasma spheroidization parameters are as follows: the power is 40kW, the argon flow is 60SCFH, the hydrogen flow is 6SCFH, and the powder feeding rate is 5.0 RPM.

Performing SEM representation on the prepared composite powder, wherein the prepared composite powder is in a spherical shape with a compact and smooth surface and has a particle size distribution of 20-80 microns according to a representation result; according to the cross section SEM characterization result, the prepared composite powder has no obvious defect holes, and the modified additive is well combined with the bulk substance. The XRD spectrogram of the prepared composite powder has characteristic peaks of hafnium diboride and tantalum disilicide, so that the tantalum disilicide is successfully added into the composite powder, and no component transformation exists in the preparation process.

Example 3

(1) Adding 916.7g of hafnium diboride, 83.3g of tantalum disilicide, 5g of PVA and 1500g of deionized water into a ball milling tank, wherein the ball-to-material ratio is 4:1, and carrying out ball milling for 4h at 300r/min to uniformly mix the components to obtain a suspension of precursor powder;

(2) transferring the suspension obtained in the step (1) to a spray drying granulation tower for agglomeration granulation, putting the granulated powder into a 120 ℃ oven for drying for 25h, and then performing inspection screening to obtain HfB with the particle size of less than 105 mu m₂-TaSi₂Agglomerated powder (HfB)₂With TaSi₂The volume ratio is 9: 1);

wherein, the spray drying granulation parameters are as follows: the inlet temperature is 250 ℃, the outlet temperature is 130 ℃, the rotating speed of the spray head is 40Hz, and the rotating speed of the peristaltic pump is 35 rpm;

(3) to HfB₂-TaSi₂Sending the agglomerated powder into an induction plasma spheroidizing device for spheroidizing, collecting the spheroidized powder through deionized water, pouring the collected powder into the deionized water and carrying out ultrasonic treatment for 20min, finally pouring out turbid liquid to only leave bottom sediments, placing the turbid liquid in a drying oven at 100 ℃ for drying for 30h, and then passing through a test sieve to obtain hafnium diboride-tantalum disilicide composite powder;

wherein, the induction plasma spheroidization parameters are as follows: the power is 40kW, the argon flow is 60SCFH, the hydrogen flow is 6SCFH, and the powder feeding rate is 5.0 RPM.

Performing SEM representation on the prepared composite powder, wherein the prepared composite powder is in a spherical shape with a compact and smooth surface and has a particle size distribution of 20-80 microns according to a representation result; according to the cross section SEM characterization result, the prepared composite powder has no obvious defect holes, and the modified additive is well combined with the bulk substance. The XRD spectrogram of the prepared composite powder has characteristic peaks of hafnium diboride and tantalum disilicide, so that the tantalum disilicide is successfully added into the composite powder, and no component transformation exists in the preparation process.

Comparative example 1

Comparative example 1 differs from example 1 in HfB₂With TaSi₂The volume ratio is 1:1, and the other operations are the same, so that the hafnium diboride-tantalum disilicide composite powder is obtained.

Comparative example 2

The difference between the comparative example 2 and the example 1 is that the pure hafnium diboride powder is obtained by omitting the addition of tantalum disilicide and the rest of the operation is the same.

Performance testing

Fluidity and apparent Density of powder

HfB before spheroidization in examples 1 to 3₂-TaSi₂The agglomerated powder and the fluidity and apparent density of the obtained hafnium diboride-tantalum disilicide composite powder after spheroidization were tested, and the obtained results are shown in table 1.

TABLE 1 flowability and packing Density of powder before and after spheroidization in examples 1-3

As can be seen from Table 1, the fluidity and the apparent density of the spheroidized powder are greatly improved, which is beneficial to preparing the hafnium diboride-tantalum disilicide composite coating by using a spraying method.

Oxyacetylene ablation examination of (II) coatings

The powder obtained in the examples 1-3 and the powder obtained in the comparative examples 1-2 are prepared into a coating by adopting a hot pressing process, the hot pressing process is carried out in a graphite resistance furnace with the vacuum level of 100Pa, argon is filled in the furnace, and the hot pressing conditions are as follows: heating to 1900 deg.C at a heating rate of 30 deg.C/min, maintaining for 20min, and cooling.

A Scanning Electron Micrograph (SEM) of a cross section of the coating obtained in example 1 is shown in FIG. 5. As can be seen from fig. 5, the resulting coating was almost crack-free, had a small amount of voids and was relatively dense. The cross-sectional scanning electron micrographs of the coatings obtained in examples 2 to 3 are similar to those in FIG. 5.

The oxidation resistance of the coatings prepared from the powders obtained in examples 1-3 and comparative examples 1-2 was examined at 1750 ℃ by using an oxygen-acetylene flame, and the results of the mass loss rate are shown in table 2.

TABLE 2 Mass loss Rate results for coatings

Group of	Mass loss rate (g/s)
		Example 1	5.79×10-4
Example 2	3.57×10-4
		Example 3	8.63×10-4
Comparative example 1	2.83×10-3
		Comparative example 2	4.65×10-3

As can be seen from Table 1, the coating prepared from the powder of the invention has a lower mass loss rate than that of the conventional ultrahigh-temperature ceramic coating by 10 after being examined by oxyacetylene ablation^-3This magnitude indicates that the addition of tantalum disilicide plays a role in enhancing the anti-oxidation ablation performance of the ultrahigh-temperature ceramic coating. However, when the amount of tantalum disilicide added is too large, the mass loss rate is rather high, and the high-temperature oxidation resistance of the coating is adversely affected. This indicates that the amount of tantalum disilicide added needs to be controlled within a reasonable range.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.