A carbon-doped hafnium nitride nanocrystalline film and its preparation method

Abstract

The present invention discloses a carbon-doped hafnium nitride nanocrystalline film, the chemical formula of which is HfC x N 1‑x ; wherein x is 0.09 to 0.1. The present invention also discloses a method for preparing the carbon-doped hafnium nitride nanocrystalline film, which adopts a magnetron co-sputtering method, specifically: placing a pure hafnium target and a graphite target in a chamber, and evacuating the chamber to a vacuum of 4×10 ‑ 4 Pa; nitrogen and argon are continuously introduced into the chamber to control the sputtering current of the pure hafnium target and graphite target, and HfC is deposited on the substrate. x N 1‑x The present invention introduces the C element into HfN to produce a hafnium carbonitride nanocrystalline film with extremely low infrared emissivity and excellent durability.

Description

Technical Field

[0001] The present invention relates to a carbon-doped hafnium nitride nanocrystalline film and also relates to a preparation method of the hafnium nitride nanocrystalline film. Background Art

[0002] Traditional infrared stealth film materials are primarily pure metals such as aluminum, silver, gold, and copper. While these materials have very low infrared emissivity, they suffer from poor environmental durability, such as low hardness, low melting point, and poor corrosion resistance. Transition metal nitrides such as HfN, while offering excellent durability properties such as high hardness, high melting point, and wear and corrosion resistance, have infrared emissivities far higher than pure metals, exhibiting poor infrared stealth properties. Therefore, they cannot be directly used as infrared stealth materials. Summary of the Invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a carbon-doped hafnium nitride nanocrystalline film. When used as an infrared stealth material, the hafnium nitride nanocrystalline film has high hardness, high melting point, good wear and corrosion resistance, and also has extremely low infrared emissivity. Another purpose of the present invention is to provide a method for preparing the above-mentioned hafnium nitride nanocrystalline film.

[0004] Technical solution: The carbon-doped hafnium nitride nanocrystalline film of the present invention has the chemical formula HfC x N 1-x ; Among them, the value of x is 0.09~0.1.

[0005] The material of the present invention is a film composed of three elements: Hf, C, and N. x N 1-x The membrane has a single-phase rock salt solid solution structure.

[0006] Among them, HfC x N 1-x The average grain size of the film is less than 10 nm.

[0007] Among them, HfC x N 1-x In the film, the content of C element is 9 at. to 10 at.%, preferably 9 at.%.

[0008] The preparation method of the carbon-doped hafnium nitride nanocrystalline film adopts a magnetron co-sputtering method, specifically: a pure hafnium target and a graphite target are placed in a chamber, and the vacuum is evacuated to 4×10 -4 Pa; nitrogen and argon are continuously introduced into the chamber to control the sputtering current of the pure hafnium target and graphite target, and HfC is deposited on the substrate. x N 1-x membrane.

[0009] The flow ratio of nitrogen to argon is 0.1 to 1:40.

[0010] Among them, both pure hafnium target and graphite target use DC medium frequency pulse power supply. The sputtering current of pure hafnium target is 0.4~0.5A, pulse width is 4~5μs, and pulse frequency is 100~120kHz; the sputtering current of graphite target is 0.1~0.2A, pulse width is 4~5μs, and pulse frequency is 100~120kHz.

[0011] The sputtering conditions are as follows: the distance between the target and the sample stage is 110-120 mm, the substrate temperature is 500-550° C., the working gas pressure is 0.8-0.85 Pa, the sample stage rotation speed is 10-12 r / min, and the sputtering time is 100-120 min.

[0012] The present invention introduces the element C into HfN to produce a carbon / hafnium nitride nanocrystalline film with extremely low infrared emissivity and excellent durability. After C doping, the bonding strength between Hf and N can be effectively improved, which not only increases the hardness of hafnium nitride to 33.5GPa, but also weakens the material's absorption intensity of infrared light, thereby significantly reducing the material's infrared emissivity.

[0013] Beneficial effects: Compared with the existing technology, the present invention has the following significant effects: the average infrared emissivity of the hafnium carbonitride nanocrystalline film material prepared by the present invention in the infrared bands of 3-5μm and 8-14μm is 0.08 and 0.03 respectively, the hardness reaches 33.5GPa, and the self-corrosion current density in 3.5wt.% NaCl solution is 1×10 -7 A.cm -2 , which shows that the nanocrystalline film material of the present invention not only has extremely low infrared emissivity, but also has excellent durability. It is expected to be used as an infrared stealth durable film in harsh environments such as high-speed solid-liquid particle collision, high temperature and corrosive liquid gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the infrared emissivity of the hafnium carbonitride nanocrystalline film prepared in Example 1;

[0015] Figure 2 is the XRD pattern of the hafnium carbonitride nanocrystalline film prepared in Example 1;

[0016] Figure 3 TEM image of the hafnium carbonitride nanocrystalline film prepared in Example 1;

[0017] Figure 4 1 is the hardness-displacement curve of the hafnium carbonitride nanocrystalline film prepared in Example 1;

[0018] Figure 5 1 is the potentiodynamic polarization curve of the hafnium carbonitride nanocrystalline film prepared in Example 1;

[0019] Figure 6 Comparison of infrared emissivity of hafnium carbonitride nanocrystalline films prepared in Comparative Examples 1 and 2 with that in Example 1;

[0020] Figure 7 The hardness of the hafnium carbonitride nanocrystalline films prepared in Comparative Examples 1 and 2 is compared with that in Example 1;

[0021] Figure 8 The corrosion resistance of the hafnium carbonitride nanocrystalline films prepared in Comparative Examples 1 and 2 is compared with that in Example 1. DETAILED DESCRIPTION

[0022] Example 1

[0023] The carbon-doped hafnium nitride nanocrystalline film of the present invention is composed of three elements: Hf, C, and N. Its chemical formula is HfC x N 1-x ; Among them, the value of x is 0.09, that is, the C content is 9at.%.

[0024] The method for preparing the carbon-doped hafnium nitride nanocrystalline film adopts a magnetron co-sputtering method and specifically includes the following steps:

[0025] (1) A silicon wafer was selected as the substrate, and the substrate was ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water, and then dried;

[0026] (2) Place the pure hafnium target and graphite target in the chamber, adjust the target-substrate distance to 110 mm, and evacuate to 4 × 10 -4 Pa, the substrate was heated to 500 ° C, and the pure hafnium target used a DC medium-frequency pulse power supply with a sputtering current of 0.4 A, a pulse width of 4 μs, and a pulse frequency of 100 kHz; the graphite target also used a DC medium-frequency pulse power supply with a sputtering current of 0.1 A, a pulse width of 4 μs, and a pulse frequency of 100 kHz;

[0027] (3) Nitrogen and argon were continuously introduced into the chamber, wherein the nitrogen flow rate was 0.5 sccm, the argon flow rate was 40 sccm, the working pressure was 0.8 Pa, the sample rotation speed was 10 r / min, and a carbon-doped hafnium nitride nanocrystalline film was deposited on the substrate. The sputtering time was 120 min, and after sputtering, HfC with an x ​​value of 0.09 was obtained. x N 1-x membrane.

[0028] like Figure 1 As shown in FIG. 1 , the average infrared emissivity of the hafnium carbonitride nanocrystalline film material prepared in Example 1 in the infrared bands of 3-5 μm and 8-14 μm is only 0.08 and 0.03, respectively. Figure 2 As shown in FIG, the hafnium carbonitride nanocrystalline film material prepared in Example 1 has a face-centered cubic single-phase solid solution structure. Figure 3 As shown in FIG, the average grain size of the hafnium carbonitride nanocrystalline film material prepared in Example 1 is only 5 nm. Figure 4 As shown in FIG, the hardness of the hafnium carbonitride nanocrystalline film material prepared in Example 1 reaches 33.5 GPa. Figure 5 As shown in the figure, the self-corrosion current density of the hafnium carbonitride nanocrystalline film material prepared in Example 1 in a 3.5 wt.% NaCl solution is 1×10 -7 A.cm -2 .

[0029] Example 2

[0030] The carbon-doped hafnium nitride nanocrystalline film of the present invention is composed of three elements: Hf, C, and N. Its chemical formula is HfC x N 1-x ; Among them, x is 0.1, that is, the C content is 10at.%.

[0031] The method for preparing the carbon-doped hafnium nitride nanocrystalline film adopts a magnetron co-sputtering method and specifically includes the following steps:

[0032] (1) A silicon wafer was selected as the substrate, and the substrate was ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water, and then dried;

[0033] (2) Place the pure hafnium target and graphite target in the chamber, adjust the target-substrate distance to 110 mm, and evacuate to 4 × 10 -4 Pa, the substrate was heated to 500 ° C, and the pure hafnium target used a DC medium-frequency pulse power supply with a sputtering current of 0.4 A, a pulse width of 4 μs, and a pulse frequency of 100 kHz; the graphite target also used a DC medium-frequency pulse power supply with a sputtering current of 0.1 A, a pulse width of 4.5 μs, and a pulse frequency of 100 kHz;

[0034] (3) Nitrogen and argon were continuously introduced into the chamber, wherein the nitrogen flow rate was 0.5 sccm, the argon flow rate was 40 sccm, the working pressure was 0.8 Pa, the sample stage speed was 10 r / min, and a carbon-doped hafnium nitride nanocrystalline film was deposited on the substrate. The sputtering time was 120 min, and after sputtering, HfC with an x ​​value of 0.1 was obtained. x N 1-x membrane.

[0035] Comparative Example 1

[0036] A hafnium nitride nanocrystalline film material is composed of two elements, Hf and N, with a C content of 0 at.%.

[0037] The preparation method of the hafnium nitride nanocrystalline film material adopts a magnetron co-sputtering method and specifically includes the following steps:

[0038] (1) A silicon wafer was selected as the substrate, and the substrate was ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water, and then dried;

[0039] (2) Place the pure hafnium target and graphite target in the chamber, adjust the target-substrate distance to 110 mm, and evacuate to 4 × 10 -4 Pa, the substrate was heated to 500 ° C, the pure hafnium target used a DC medium frequency pulse power supply, the sputtering current was set to 0.4A, the pulse width was 4μs, and the pulse frequency was 100kHz; the graphite target also used a DC medium frequency pulse power supply, and the sputtering current was set to 0A;

[0040] (3) Nitrogen and argon were continuously introduced into the chamber, wherein the nitrogen flow rate was 0.5 sccm, the argon flow rate was 40 sccm, the working gas pressure was 0.8 Pa, the sample stage speed was 10 r / min, and a carbon-doped hafnium nitride nanocrystalline film was deposited on the substrate. The sputtering time was 120 min, and an HfN film was obtained after sputtering.

[0041] Comparative Example 2

[0042] The carbon-doped hafnium nitride nanocrystalline film of the present invention is composed of three elements: Hf, C, and N. Its chemical formula is HfC x N 1-x ; Among them, the value of x is 0.26, that is, the C content is 26at.%.

[0043] The method for preparing the carbon-doped hafnium nitride nanocrystalline film adopts a magnetron co-sputtering method and specifically includes the following steps:

[0044] (1) A silicon wafer was selected as the substrate, and the substrate was ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water, and then dried;

[0045] (2) Place the pure hafnium target and graphite target in the chamber, adjust the target-substrate distance to 110 mm, and evacuate to 4 × 10 -4 Pa, the substrate was heated to 500 ° C, and the pure hafnium target used a DC medium-frequency pulse power supply with a sputtering current of 0.4 A, a pulse width of 4 μs, and a pulse frequency of 100 kHz; the graphite target also used a DC medium-frequency pulse power supply with a sputtering current of 0.2 A, a pulse width of 4 μs, and a pulse frequency of 100 kHz;

[0046] (3) Nitrogen and argon were continuously introduced into the chamber, wherein the nitrogen flow rate was 0.5 sccm, the argon flow rate was 40 sccm, the working pressure was 0.8 Pa, the sample stage speed was 10 r / min, and a carbon-doped hafnium nitride nanocrystalline film was deposited on the substrate. The sputtering time was 120 min, and after sputtering, HfC with an x ​​value of 0.26 was obtained. x N 1-x membrane.

[0047] Figure 6 The results show that the reflectivity of the sample in comparative example 1 to infrared light with a wavelength of 2000nm is 79%, that is, the emissivity is 0.21, the emissivity of the sample in comparative example 2 to infrared light with a wavelength of 2000nm is 0.16, and the emissivity of the sample in embodiment 1 to infrared light with a wavelength of 2000nm is only 0.12. Figure 7 The results show that the hardness of the sample of Comparative Example 1 is 26.5 GPa, the hardness of the sample of Comparative Example 2 is 28.2 GPa, and the hardness of the sample of Example 1 is 33.5 GPa. Figure 8 The results show that the sample of Example 1 has a more positive corrosion potential and a lower corrosion current density than the samples of Comparative Examples 1 and 2. Figures 6-8 By comparison, it can be seen that Example 1 has the lowest infrared emissivity, the highest hardness and the best corrosion resistance. This is because, on the one hand, carbon doping enhances the bonding strength of hafnium nitride and weakens the lattice vibration absorption effect, thereby effectively reducing the infrared emissivity; on the other hand, carbon doping refines the grain size of hafnium nitride, thereby improving the hardness and corrosion resistance of hafnium nitride.

Claims

1. A carbon-doped hafnium nitride nanocrystalline film, characterized in that: Its chemical formula is HfC x N 1-x ; Among them, the value of x is 0.09~0.

1.

2. The carbon-doped hafnium nitride nanocrystalline film according to claim 1, wherein: HfC x N 1-x The membrane has a single-phase rock salt solid solution structure.

3. The carbon-doped hafnium nitride nanocrystalline film according to claim 1, wherein: HfC x N 1-x The average grain size in the film is less than 10 nm.

4. The carbon-doped hafnium nitride nanocrystalline film according to claim 1, wherein: HfC x N 1-x The content of element C in the film is 9 at.%.

5. The method for preparing the carbon-doped hafnium nitride nanocrystalline film according to claim 1, wherein: The magnetron co-sputtering method is used, specifically: a pure hafnium target and a graphite target are placed in a chamber and vacuumed to 4×10 -4 Pa; nitrogen and argon are continuously introduced into the chamber to control the sputtering current of the pure hafnium target and graphite target, and HfC is deposited on the substrate. x N 1-x membrane.

6. The preparation method according to claim 5, characterized in that: The flow ratio of the nitrogen gas to the argon gas is 0.1 to 1:

40.

7. The preparation method according to claim 5, characterized in that: Both the pure hafnium target and the graphite target use a DC medium-frequency pulse power supply. The sputtering current of the pure hafnium target is 0.4-0.5A, the pulse width is 4-5μs, and the pulse frequency is 100-120kHz; the sputtering current of the graphite target is 0.1-0.2A, the pulse width is 4-5μs, and the pulse frequency is 100-120kHz.

8. The preparation method according to claim 5, characterized in that: The sputtering conditions are as follows: target-substrate distance of 110-120 mm, substrate temperature of 500-550° C., working gas pressure of 0.8-0.85 Pa, sample stage rotation speed of 10-12 r / min, and sputtering time of 100-120 min.

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