CN111943678A - HfxZr1-xC ceramic solid solution nanowire and preparation method thereof - Google Patents

Abstract

The invention relates to Hf_xZr_1‑xThe preparation method of the C ceramic solid solution nanowire comprises the steps of respectively weighing precursors with different masses and configuring the precursors according to different molar ratios. Preparing Hf on the surface of carbon/carbon composite material by Low Pressure Chemical Vapor Deposition (LPCVD) technology_xZr_1‑xC solid solution nanowires. The atom molar ratio in the solid solution nanowire can be regulated and controlled by regulating and controlling the content of each component in the mixed precursor powder, and the microstructure of the solid solution nanowire can be effectively controlled by regulating and controlling LPCVD process parameters. Book (I)The preparation process is simple and easy to operate, can effectively control the shape of the nanowire, and expands the application of the nanowire in various material fields.

Description

HfxZr1-xC ceramic solid solution nanowire and preparation method thereof

Technical Field

The invention belongs to the technical field of nano materials, and relates to Hf_xZr_1-xC ceramic solid solution nano-wire and a preparation method thereof.

Background

The ultrahigh-temperature ceramic carbide (HfC, ZrC and the like) has high melting point, high hardness, excellent physical and chemical properties and good ablation resistance, and one-dimensional nanowire/tube material of the ultrahigh-temperature ceramic carbide has the advantages of both bulk ceramic and bulk ceramicThe excellent performance of the porcelain and the unique geometric characteristics of the one-dimensional nano material are ideal strengthening and toughening reinforcement materials of the composite material, but the inherent brittleness of the ultra-high temperature ceramics reduces the strengthening and toughening effect of the ultra-high temperature ceramics. Since HfC and ZrC have similar crystal structures and the atomic radii of Hf and Zr are close, a continuous solid solution can be formed. Formed solid solution structure Hf_xZr_1-xC can inhibit the transformation of a crystal structure at high temperature, reduce the volume effect, have certain activation effect and can improve the toughness and the high-temperature stability of the nanowire, so the Hf_xZr_1-xThe C ceramic solid solution nanowire is a composite material strengthening and toughening reinforcement material with great application prospect.

CN102730685A discloses a method for preparing one-dimensional hafnium carbide nanowires, which comprises pretreating a graphite substrate, and controlling corresponding process parameters by using a CVD technique. Finally, the one-dimensional hafnium carbide nano-wire and the nano-belt are prepared on the graphite substrate.

CN109706434A discloses a solid solution nanowire and a preparation method and application thereof, wherein gold spraying is carried out on a silicon wafer through magnetron sputtering to be used as a catalyst of the solid solution nanowire. And then heating the mixture of InP and ZnSe, and carrying out chemical vapor deposition reaction in a high-temperature region under the action of carrier gas to prepare the InP-ZnSe solid solution nanowire.

The document 1 "Ghaffari S A, Faghhi-Sani M A, Golestani-Fard F, et al.Difusion and solution analysis for between the binary systems of TaC, HfC and ZrC. International Journal of Refractory Metals and Hard Materials,2013,41: 180-" reports the evolution of the phase transition, the formation of the solid solution and the diffusion behavior of the HfC-ZrC binary system. The research finds the process of forming solid solution of ZrC and HfC and the diffusion behavior of ZrC in HfC.

Thus, it is demonstrated that HfC and ZrC form Hf_xZr_1-xThe feasibility of the C ceramic solid solution is proved, and the formed solid solution structure takes the crystal structure of HfC as a framework, and ZrC is diffused in the crystal structure of HfC to form a mixed symmetrical interstitial solid solution.

Document 3J C Ren, Y L Zhang, P F Zhang, et al, alignment resistance of HfC coating formed by HfC nanowire in cyclic alignment, journal of the European Ceramic Society,2017,37(8): 2759) 2768 document reports toughening of coating using HfC nanowires during cyclic ablation, improving the protection of C/C composites against ablation. It is demonstrated that the toughening of the coating by the nano-wires can effectively alleviate the generation of coating defects. However, oxidation of the HfC nanowires occurs with the ablation process, the toughening effect on the coating is lost, and the coating rapidly fails.

Document 4, "Silvestoni L, Sciti D, Balat-Pichelin M, et al, zirconium carbide nanoparticles with a titanium silicate," micro structure, mechanical properties and high temperature oxidation. materials Chemistry and Physics,2013,143(1):407-415, "reports that the synergistic effect exhibited by various transition metal oxides during oxidation can effectively improve their oxidation resistance.

In conventional applications of single-phase nanowires to toughen coatings, rapid and severe oxidation inevitably occurs, resulting in loss of the toughening effect. Meanwhile, the structural morphology of the nanowire can also affect the toughening effect. Due to Hf_xZr_{1- x}The microstructure morphology of the C ceramic solid solution nanowire and the proportion content of the solid solution components can be adjusted according to the proportion content of the process and the precursor, and various oxides formed in the oxidation process can generate synergistic action, so that the oxidation resistance of the nanowire is improved, the toughening effect of the nanowire on the coating is continuously exerted, and the C ceramic solid solution nanowire has great potential in the application field. However, the preparation and application of the ceramic solid solution nanowire are not reported at present. Thus, for the preparation of Hf_xZr_1-xThe C ceramic solid solution nano-wire has important significance.

Disclosure of Invention

Technical problem to be solved

In order to avoid the defects of the prior art, the invention provides Hf_xZr_1-xC ceramic solid solution nano-wire and a preparation method thereof.

Technical scheme

Hf_xZr_1-xC ceramic solid solution nanowires, characterized in that: preparing Hf on the surface of carbon/carbon composite material_xZr_1-xC solid solution nanowire, Hf_xZr_1-xC, the ceramic solid solution nanowires are distributed in a crossed mode, and the shape of the ceramic solid solution nanowires presents a quadrangular prism structure.

The diameter of the nanowire is 40-150 nm.

Preparing the Hf_xZr_1-xThe method for preparing the C ceramic solid solution nanowire is characterized by comprising the following steps of:

step 1: polishing the C/C composite material substrate, then ultrasonically cleaning for 10-30min and drying;

step 2: adding Ni (NO) with absolute ethyl alcohol₃)₂Preparing a solution with the concentration of 0.5-1.2 mol/L;

and step 3: putting the C/C composite material into Ni (NO)₃)₂Soaking the solution for 7-10 h, and then drying the solution in an oven at the temperature of 80 ℃ for 2-6 h to obtain a primary sample;

step 4, preparing Hf by using low-pressure chemical vapor deposition method_xZr_1-xC, nano-wire:

step S1: suspending the dried initial sample in a tubular chemical vapor deposition furnace, and placing the dried initial sample in HfCl with a molar ratio of 3-7: 7-3₄And ZrCl₄Powder is put in the volatilization container;

step S2: pumping the pressure in the tubular chemical vapor deposition furnace to 5-10kPa, heating to 1000-1200 ℃, and introducing Ar and H in the heating process₂Gas is introduced at the flow rates of 200-400 ml/min and 0.5-1.0L/min respectively; keeping the temperature at 1150 ℃ for 1-2 h, and simultaneously introducing CH₄Gas with the flow rate of 20-80 ml/min, and stopping introducing CH after the heat preservation is finished₄And H₂A gas;

step S3: when the temperature in the chemical vapor deposition furnace is reduced to 350 ℃, stopping introducing Ar gas, naturally cooling along with the tubular chemical vapor deposition furnace, and depositing on a C/C composite material matrix to obtain Hf_xZr_1-xAnd C, nano wires.

And (3) drying in the step (1) by using an oven.

And step S2, the pressure in the tubular chemical vapor deposition furnace is pumped to 5-10kPa by using a vacuum pump.

In the step S2, the temperature is raised to 1000-1200 ℃ at a rate of 7 ℃/min.

Advantageous effects

The invention provides Hf_xZr_1-xThe preparation method of the C ceramic solid solution nanowire comprises the steps of respectively weighing precursors with different masses and configuring the precursors according to different molar ratios. Preparing Hf on the surface of carbon/carbon composite material by Low Pressure Chemical Vapor Deposition (LPCVD) technology_xZr_1-xC solid solution nanowires. The atom molar ratio in the solid solution nanowire can be regulated and controlled by regulating and controlling the content of each component in the mixed precursor powder, and the microstructure of the solid solution nanowire can be effectively controlled by regulating and controlling LPCVD process parameters. The invention prepares Hf on the surface of the carbon/carbon composite material_xZr_1-xC solid solution nanowire, Hf_xZr_1-xC, the ceramic solid solution nanowires are distributed in a crossed mode, and the shape of the ceramic solid solution nanowires presents a quadrangular prism structure. The diameter of the nanowire is 40-150 nm.

Compared with the prior art, the invention has the beneficial effects that: hf of the invention_xZr_1-xThe C ceramic solid solution nanowire is in cross distribution, the shape of the nanowire presents a quadrangular prism structure, the nanowire is distributed in a relatively dispersed mode, the C ceramic solid solution nanowire can be used for toughening the ablation-resistant and oxidation-resistant complex phase coating, and the C ceramic solid solution nanowire has the performance advantages of being large in specific surface area, dispersed and relatively good in phase compatibility and capable of being uniformly distributed in the coating. The special potential of oxidation resistance and ablation can be fully exerted, and the toughening effect on the composite material under the extreme environment is realized. The diameter of the nanowire is 40-150nm, and the thin solid solution nanowire can be expanded to be applied to the field of electricity. The preparation process is simple and easy to operate, can effectively control the shape of the nanowire, and expands the application of the nanowire in various material fields. Is suitable for being applied to the preparation of various materials.

Drawings

FIG. 1 is Hf_0.3Zr_0.7A microscopic topography of the C solid solution nanowire;

FIG. 2 is Hf_0.5Zr_0.5A microscopic topography of the C solid solution nanowire;

FIG. 3 is Hf_0.7Zr_0.3A microscopic topography of the C solid solution nanowire;

FIG. 4 is Hf_0.5Zr_0.5C, element content distribution diagram of the solid solution nanowire;

FIG. 5 is Hf_0.5Zr_0.5High resolution of TEM of the C solid solution nanowire and selection of an electron diffraction pattern.

Detailed Description

The invention will now be further described with reference to the following examples and drawings:

the invention aims to provide a preparation method of the solid solution nanowire, which is simple in preparation process and easy to operate, so that the high-temperature-resistant solid solution nanowire can be prepared at a lower temperature, and the toughening performance of the nanowire can be improved. Thereby achieving a new breakthrough in the preparation of the solid solution nano material, fully utilizing the advantages and the potential of the solid solution compound and realizing the toughening effect on the composite material in the ultra-high temperature extreme environment.

Example 1:

novel Hf_xZr_1-xThe preparation method of the C ceramic solid solution nanowire comprises the following steps:

step S1: polishing a C/C composite material matrix with the size of (8mm by 2mm), ultrasonically cleaning for 10-30min, and drying in an oven for later use;

step S2: using absolute ethyl alcohol to react Ni (NO)₃)₂Preparing a solution with the concentration of 0.5 mol/L;

step S3: the prepared C/C composite material is put into the Ni (NO) prepared in step S2₃)₂Soaking the solution for 8h, and then drying the solution in an oven at the temperature of 80 ℃ for 4h to obtain a primary sample;

step S4: preparation of Hf by LPCVD_xZr_1-xThe specific method of the C nanowire is as follows:

step S41: placing the dried sample in the step S3 into a tubeWeighing HfCl in a chemical vapor deposition furnace according to a molar ratio of 3:7₄And ZrCl₄Powder is put in the volatilization container;

step S42: pumping the pressure in the tubular chemical vapor deposition furnace to 5kPa by using a vacuum pump, then heating to 1100 ℃ at the heating rate of 7 ℃/min, and introducing Ar and H in the heating process₂Gas is introduced at the flow rates of 300ml/min and 0.8L/min respectively; keeping the temperature at 1100 ℃ for 1h, and simultaneously introducing CH₄Gas with a flow rate of 50ml/min, closing CH after heat preservation is finished₄And H₂A gas switch;

step S43: if the temperature in the chemical vapor deposition furnace is reduced to 350 ℃, an Ar gas switch and a power switch are sequentially closed; naturally cooling along with the tubular chemical vapor deposition furnace, namely depositing on a C/C composite material matrix to obtain Hf_xZr_1-xAnd C, nano wires.

Hf prepared by the above procedure_0.3Zr_0.7The nanowire is shown in fig. 1, and the nanowire cross distribution can be seen from the figure, and the morphology of the nanowire shows a quadrangular prism structure. The nano wires are distributed in a dispersed manner, can be used for toughening the ablation-resistant and oxidation-resistant complex phase coating, and can be uniformly distributed in the coating due to the large specific surface area, the dispersion and the good phase compatibility, so that the performance advantage of the solid solution nano wires is exerted.

Example 2

Novel Hf_xZr_1-xThe preparation method of the C ceramic solid solution nanowire comprises the following steps:

step S1: polishing a C/C composite material matrix with the size of (8mm by 2mm), ultrasonically cleaning for 10-30min, and drying in an oven for later use;

step S2: using absolute ethyl alcohol to react Ni (NO)₃)₂Preparing a solution with the concentration of 0.8 mol/L;

step S3: the prepared C/C composite material is put into the Ni (NO) prepared in step S2₃)₂Soaking the solution for 8h, and then drying the solution in an oven at the temperature of 80 ℃ for 4h to obtain a primary sample;

step S4: using LPCVDPreparation of Hf_xZr_1-xThe specific method of the C nanowire is as follows:

step S41: suspending the dried initial sample in the step S3 in a tubular chemical vapor deposition furnace, and weighing HfCl according to the molar ratio of 5:5₄And ZrCl₄Powder is put in the volatilization container;

step S42: pumping the pressure in the tubular chemical vapor deposition furnace to 7kPa by using a vacuum pump, then heating to 1150 ℃ at the heating rate of 7 ℃/min, and introducing Ar and H in the heating process₂Gas is introduced at the flow rates of 200ml/min and 1.0L/min respectively; keeping the temperature at 1150 ℃ for 1.5h, and simultaneously introducing CH₄Gas flow rate of 60ml/min, and closing CH after heat preservation₄And H₂A gas switch;

step S43: if the temperature in the chemical vapor deposition furnace is reduced to 350 ℃, an Ar gas switch and a power switch are sequentially closed; naturally cooling along with the tubular chemical vapor deposition furnace, namely depositing on a C/C composite material matrix to obtain Hf_0.5Zr_0.5And C, nano wires.

Hf prepared by the above procedure_0.5Zr_0.5The C nanowire is shown in FIG. 2; hf (hafnium)_0.5Zr_0.5The element distribution of the C nanowire is shown in fig. 4 and the electron diffraction pattern and high resolution image are shown in fig. 5. It can be seen that the solid solution nanowire elements are uniformly distributed, the diameters of the nanowires are uniformly distributed, and the solid solution nanowire Hf can be further prepared according to the fact that the single-phase nanowire HfC has better field emission performance_0.5Zr_0.5And C is used for field emission test and expands the application field of the field emission test.

Example 3

Novel Hf_xZr_1-xThe preparation method of the C ceramic solid solution nanowire comprises the following steps:

step S1: polishing a C/C composite material matrix with the size of (8mm by 2mm), ultrasonically cleaning for 10-30min, and drying in an oven for later use;

step S2: using absolute ethyl alcohol to react Ni (NO)₃)₂Preparing a solution with the concentration of 1.0 mol/L;

step S3: will makeThe prepared C/C composite material is put into the Ni (NO) prepared in step S2₃)₂Soaking the solution for 8h, and then drying the solution in an oven at the temperature of 80 ℃ for 4h to obtain a primary sample;

step S4: preparation of Hf by LPCVD_xZr_1-xThe specific method of the C nanowire is as follows:

step S41: placing the dried initial sample in the step S3 in a tubular chemical vapor deposition furnace in a hanging manner, and weighing HfCl according to the molar ratio of 7:3₄And ZrCl₄Powder is put in the volatilization container;

step S42: pumping the pressure in the tubular chemical vapor deposition furnace to 9kPa by using a vacuum pump, then heating to 1200 ℃ at the heating rate of 7 ℃/min₂Gas is introduced at the flow rates of 300ml/min and 0.8L/min respectively; keeping the temperature at 1200 ℃ for 2h, and simultaneously introducing CH₄Gas with a flow rate of 30ml/min, closing CH after heat preservation is finished₄And H₂A gas switch;

step S43: if the temperature in the chemical vapor deposition furnace is reduced to 350 ℃, an Ar gas switch and a power switch are sequentially closed; naturally cooling along with the tubular chemical vapor deposition furnace, namely depositing on a C/C composite material matrix to obtain Hf_0.7Zr_0.3And C, nano wires.

Hf prepared by the above procedure_0.7Zr_0.3C nanowires as shown in fig. 3, compared with fig. 1 and fig. 2, the distribution density of nanowires is increased, the diameter is reduced (40-150nm), and the thin solid solution nanowires can be expanded to be applied in the electrical field.

Hf prepared by using preparation method of the invention_xZr_1-xThe C solid solution nanowire can fully exert the unique potential of oxidation resistance and ablation resistance, and realize the toughening effect on the composite material in an extreme environment.

Claims (6)

1. Hf_xZr_1-xC ceramic solid solution nanowires, characterized in that: preparing Hf on the surface of carbon/carbon composite material_xZr_{1- x}C solid solution nanowire, Hf_xZr_1-xSolid solution of C ceramicThe bulk nanowires are distributed in a crossed mode, and the shape of the bulk nanowires is in a quadrangular prism structure.

2. The Hf of claim 1_xZr_1-xC ceramic solid solution nanowires, characterized in that: the diameter of the nanowire is 40-150 nm.

3. Preparation of the Hf of claim 1 or 2_xZr_1-xThe method for preparing the C ceramic solid solution nanowire is characterized by comprising the following steps of:

step 1: polishing the C/C composite material substrate, then ultrasonically cleaning for 10-30min and drying;

step 2: adding Ni (NO) with absolute ethyl alcohol₃)₂Preparing a solution with the concentration of 0.5-1.2 mol/L;

and step 3: putting the C/C composite material into Ni (NO)₃)₂Soaking the solution for 7-10 h, and then drying the solution in an oven at the temperature of 80 ℃ for 2-6 h to obtain a primary sample;

step 4, preparing Hf by using low-pressure chemical vapor deposition method_xZr_1-xC, nano-wire:

step S1: suspending the dried initial sample in a tubular chemical vapor deposition furnace, and placing the dried initial sample in HfCl with a molar ratio of 3-7: 7-3₄And ZrCl₄Powder is put in the volatilization container;

step S2: pumping the pressure in the tubular chemical vapor deposition furnace to 5-10kPa, heating to 1000-1200 ℃, and introducing Ar and H in the heating process₂Gas is introduced at the flow rates of 200-400 ml/min and 0.5-1.0L/min respectively; keeping the temperature at 1150 ℃ for 1-2 h, and simultaneously introducing CH₄Gas with the flow rate of 20-80 ml/min, and stopping introducing CH after the heat preservation is finished₄And H₂A gas;

step S3: when the temperature in the chemical vapor deposition furnace is reduced to 350 ℃, stopping introducing Ar gas, naturally cooling along with the tubular chemical vapor deposition furnace, and depositing on a C/C composite material matrix to obtain Hf_xZr_1-xAnd C, nano wires.

4. The method of claim 3Hf_xZr_1-xThe preparation method of the C ceramic solid solution nanowire is characterized by comprising the following steps: and (3) drying in the step (1) by using an oven.

5. The Hf of claim 3_xZr_1-xThe preparation method of the C ceramic solid solution nanowire is characterized by comprising the following steps: and step S2, the pressure in the tubular chemical vapor deposition furnace is pumped to 5-10kPa by using a vacuum pump.

6. The Hf of claim 3_xZr_1-xThe preparation method of the C ceramic solid solution nanowire is characterized by comprising the following steps: in the step S2, the temperature is raised to 1000-1200 ℃ at a rate of 7 ℃/min.

Images