Method for forming amorphous layer on multi-component boride ceramic

Abstract

The invention provides a method for forming an amorphous layer on multi-component boride ceramic, and relates to the field of ceramics, the method comprises the following steps: carrying out ball milling on transition metal boride ceramic powder and boride powder capable of forming the amorphous layer according to a ratio to prepare boride mixed powder; putting the mixed powder into a mold, heating to 1800-2000 DEG C, preserving heat for 5-15 minutes, sintering, applying a uniaxial load of 30-50 MPa when the temperature reaches 800-1000 DEG C, cooling to room temperature at a cooling speed after sintering is completed, and carrying out oxidation treatment on the obtained multi-component transition metal boride ceramic, so that an amorphous protective layer is formed on the surface of the multi-component transition metal boride ceramic. According to the invention, the boride capable of forming the amorphous layer is doped into the transition metal boride ceramic and is pre-oxidized, so that the amorphous layer is formed on the surface of the transition metal boride ceramic, and the amorphous layer improves the oxidation resistance and the wear resistance of the multi-component transition metal boride and reduces the friction coefficient of the multi-component transition metal boride.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramics, and in particular to a method for forming an amorphous layer on a multi-component boride ceramic. Background Art

[0002] Friction and wear are widespread in industrial production and high-end equipment, significantly impacting energy consumption and material loss. According to statistics, approximately 30% of global energy is lost annually due to friction, approximately 60% of mechanical components fail due to wear, and approximately 50% of serious mechanical equipment accidents are attributed to lubrication failure and severe wear. The losses caused by friction and wear are enormous, so reducing friction, minimizing wear, and optimizing lubrication have become key to improving energy efficiency and extending component life and reliability.

[0003] As engine thrust-to-weight ratios continue to increase, turbine inlet temperatures are also rising. For example, the turbine inlet temperatures of existing aircraft engines with thrust-to-weight ratios of 10-11 have reached 1500°C; for engines with thrust-to-weight ratios of 12-15, the average turbine inlet temperature is expected to exceed 1800°C. Aircraft engines operate in harsh environments, such as high speeds and high temperatures. To meet the demands of high reliability and long life, these engines are pushing material performance and manufacturing technologies to their limits. The development of key high-temperature friction pairs in Chinese aircraft engines (such as the turbine transmission shaft and sleeve, the blade shroud mating surface, and the turbine blade and outer ring) has long been constrained by the availability of high-temperature lubricating and wear-resistant materials. With the continuous improvement of thrust-to-weight ratios and the increasingly complex service environments, high-temperature friction pairs in the next generation of aircraft engines face even more demanding operating conditions. This necessitates addressing the lack of solid lubricating and wear-resistant materials and technologies capable of withstanding temperatures exceeding 1000°C, as well as the inadequate research on the damage mechanisms of friction pair interfaces in these complex, high-temperature environments.

[0004] Multi-component transition metal boride ceramics have attracted widespread attention due to their high melting point, high hardness, and excellent oxidation, corrosion, and wear resistance. However, existing multi-component transition metal boride ceramics still suffer from complex composition design and performance prediction, as well as limited high-temperature oxidation resistance. Multi-component systems involve multiple elements and phases, and the mechanisms by which phase equilibrium and microstructural evolution influence the ultimate properties are complex. While their oxidation resistance is superior to that of single borides and many other ceramics, the resulting B2O3 glass protective layer can fail due to volatilization or ineffective healing during extended service in extremely high-temperature oxidizing environments (e.g., >1200-1400°C), leading to further oxidation and even catastrophic damage to the substrate. The specific upper limit of oxidation resistance is highly dependent on composition design. Summary of the Invention

[0005] To address the technical deficiencies mentioned in the background art, the present invention proposes a method for forming an amorphous layer on a multi-component boride ceramic. This method pre-oxidizes the resulting B2O3 amorphous layer, which improves the oxidation resistance of the multi-component transition metal boride over a wide temperature range and enhances its wear resistance. This method enables the multi-component transition metal boride to exhibit significantly stronger oxidation resistance and lubricity at both room and high temperatures than previously reported multi-component transition metal boride ceramics.

[0006] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for forming an amorphous layer on a multi-component boride ceramic, comprising the following steps: Step 1: ball-milling the transition metal boride ceramic powder and the boride powder capable of forming an amorphous layer in proportion to prepare a boride mixed powder; Step 2: placing the boride mixed powder obtained in step 1 in a mold and heating it to 1800-2000°C for 5-15 minutes for sintering; applying a uniaxial load of 30-50 MPa when the temperature reaches 800-1000°C; cooling it to room temperature after sintering to obtain a crude multi-component transition metal boride ceramic; Step 3: The crude multi-component transition metal boride ceramic product obtained in step 2 after pretreatment is subjected to oxidation treatment to form an amorphous protective layer on the surface of the multi-component transition metal boride ceramic.

[0007] As a further illustration of the present invention, the transition metal boride ceramics are one to four of TaB2, TiB2, ZrB2, HfB2, ZrB2, NbB2, CrB2, and WB2.

[0008] As a further illustration of the present invention, the boride capable of forming an amorphous layer is any one of VB2, SiB2, GeB2, and MoB2.

[0009] As a further illustration of the present invention, the boride mixed powder prepared in step 1 has the molecular formula (A a B b C c D d E e )B2, where ABCD are different elements selected from Ta, Ti, Zr, Hf, Zr, Nb, Cr or W, E is an element selected from V, Si, Ge or Mo, abcd is 0 to 1 / 2, e is 1 / 5 to 1 / 2, the values of abcd not equal to 0 are equal and equal to e, and a+b+c+d+e=1.

[0010] As a further illustration of the present invention, in step 1, the ball milling process is as follows: the transition metal boride ceramic powder and the boride powder capable of forming an amorphous layer are placed in a tungsten carbide tank filled with 1 wt% stearic acid and ball milled for 4 to 24 hours at a rotation speed of 150 to 360 r / min, and the ball-to-powder ratio during the ball milling process is 2 to 5:1.

[0011] As a further illustration of the present invention, in step 2, the sintering process is as follows: the boride mixed powder obtained in step 1 is placed in a graphite mold, heated to 1800-2000°C at a heating rate of 80-120°C / min under an argon atmosphere in a spark plasma sintering furnace, kept warm for 5-15 minutes, and when the temperature reaches 800-1000°C, a uniaxial load of 30-50 MPa is applied; finally, the mixture is cooled to room temperature at a cooling rate of 80-120°C / min.

[0012] As a further illustration of the present invention, in step three, the pretreatment process of the multi-component transition metal boride ceramic crude product is: the multi-component transition metal boride ceramic crude product obtained in step two is ground to a grit size of 2000 using a diamond grinding wheel, and then surface polished using a colloidal silica suspension.

[0013] As a further illustration of the present invention, in step three, the oxidation treatment process is: heat treatment in a box-type heat treatment furnace at 800-900 ° C for 5-10 minutes.

[0014] As a further illustration of the present invention, in step three, the oxidation treatment process is: surface ablation treatment by oxyacetylene flame for 3-5 minutes.

[0015] As a further illustration of the present invention, in step three, the thickness of the formed amorphous protective layer is 100-800 μm.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention targets multi-component transition metal boride ceramics. By doping with borides (VB2, SiB2, GeB2, MoB2) that can form an amorphous layer, and pre-oxidizing the transition metal boride ceramics, an amorphous layer is formed on the surface. The amorphous layer improves the oxidation resistance and wear resistance of the multi-component transition metal boride and reduces the friction coefficient. In particular, the friction coefficient is significantly reduced to 0.13 in a high temperature environment (800-1200 °C).

[0017] Other features and advantages of this technical solution will be described in the subsequent description, and in part will become apparent from the description, or understood by practicing this technical solution. The objectives and other advantages of this technical solution can be achieved and obtained through the structures specifically pointed out in the written description and the accompanying drawings.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present technical solution and constitute a part of the specification. Together with the embodiments of the present technical solution, they are used to explain the present technical solution and do not constitute a limitation of the present technical solution. In the accompanying drawings: Attachment Figure 1 After SPS firing (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 ) XRD pattern of B2 ternary boride ceramics; Attachment Figure 2 After SPS firing (Ta 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4 ) XRD pattern of B2 quaternary boride ceramics; Attachment Figure 3 After SPS firing (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 ) XRD pattern of B2 pentaary boride ceramics; Attachment Figure 4 After SPS firing (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 ) SEM image of B2 ternary boride ceramics; Attachment Figure 5 After SPS firing (Ta 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4 ) SEM image of B2 quaternary boride ceramics; Attachment Figure 6 After SPS firing (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 ) SEM image of B2 pentaary boride ceramics; Attachment Figure 7 After pre-oxidation (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 ) Curve of friction coefficient of B2 ternary boride ceramics changing with time at 1000 °C; Attachment Figure 8 After pre-oxidation (Ta 1 / 4 Ti1 / 4 Zr 1 / 4 V 1 / 4 ) Curve of friction coefficient of B2 quaternary boride ceramics changing with time at 1000 °C; Attachment Figure 9 After pre-oxidation (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 ) Curve of friction coefficient of B2 penta-boride ceramics changing with time at 1000 °C; Attachment Figure 10 After pre-oxidation (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 ) FIB-TEM characterization of the surface layer of B2 ternary boride ceramics; (a) HAADF-STEM image of the worn cross section; (b) element distribution on the tribofilm; Attachment Figure 11 After pre-oxidation (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 ) FIB-TEM characterization of the surface layer of B2 penta-boride ceramic, where (a) is the HAADF-STEM image of the worn cross section; (b) is the element distribution on the tribofilm. DETAILED DESCRIPTION

[0020] The preferred embodiments of the present technical solution are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present technical solution and are not used to limit the present technical solution.

[0021] The present invention provides a method for forming an amorphous layer on a multi-component boride ceramic, comprising the following steps: Step 1: ball-milling the transition metal boride ceramic powder and the boride powder capable of forming an amorphous layer in proportion to prepare a boride mixed powder.

[0022] Specifically, the transition metal boride ceramics are one to four of TaB2, TiB2, ZrB2, HfB2, ZrB2, NbB2, CrB2, and WB2; the purity of each transition metal boride ceramic powder is 98~99.99%, and the particle size is 1~3um; the boride capable of forming an amorphous layer is any one of VB2, SiB2, GeB2, and MoB2.

[0023] Specifically, the boride mixed powder prepared in step 1 has the molecular formula (A a B b Cc D d E e )B2, where ABCD are different elements selected from Ta, Ti, Zr, Hf, Zr, Nb, Cr or W, E is an element selected from V, Si, Ge or Mo, abcd is 0 to 1 / 2, e is 1 / 5 to 1 / 2, the values of abcd not equal to 0 are equal and equal to e, and a+b+c+d+e=1.

[0024] The ball milling process is as follows: the transition metal boride ceramic powder and the boride powder capable of forming an amorphous layer are placed in a tungsten carbide tank filled with 1 wt% stearic acid and ball milled for 4 to 24 hours at a rotation speed of 150 to 360 r / min. The ball-to-powder ratio during the ball milling process is 2 to 5:1.

[0025] Specifically, the boride mixed powder obtained in step 1 is stored and dried in a vacuum drying oven.

[0026] Step 2: Place the boride mixed powder obtained in step 1 in a mold and heat it to 1800-2000°C for 5-15 minutes for sintering. When the temperature reaches 800-1000°C, apply a uniaxial load of 30-50 MPa. After sintering, cool it to room temperature at a cooling rate to obtain a crude multi-component transition metal boride ceramic product.

[0027] The sintering process is as follows: the boride mixed powder obtained in step 1 is loaded into a graphite mold, heated to 1800-2000°C at a heating rate of 80-120°C / min under an argon atmosphere in a spark plasma sintering furnace, kept at that temperature for 5-15 minutes, and when the temperature reaches 800-1000°C, a uniaxial load of 30-50 MPa is applied; and finally, the mold is cooled to room temperature at a cooling rate of 80-120°C / min.

[0028] Step 3: The crude multi-component transition metal boride ceramic product obtained in step 2 after pretreatment is subjected to oxidation treatment to form an amorphous protective layer on the surface of the multi-component transition metal boride ceramic.

[0029] Specifically, the pretreatment process of the crude multi-component transition metal boride ceramic product is as follows: the crude multi-component transition metal boride ceramic product obtained in step 2 is ground to a grit size of 2000 using a diamond grinding wheel, and then surface polished using a colloidal silica suspension.

[0030] The oxidation treatment process is: heat treatment in a box-type heat treatment furnace at 800~900 °C for 5~10 minutes; or surface ablation treatment by oxyacetylene flame for 3-5 minutes.

[0031] It should be noted that the sample loading in the above steps 1, 2 and 3 was all completed in a glove box with an argon atmosphere to prevent oxidation.

[0032] Specifically, the thickness of the amorphous protective layer is 100-800µm. The relative density of the multi-component transition metal boride ceramic is 95-100%, the hardness is 22-27GPa, and the fracture toughness is 3-6MPa·m. 1 / 2 .

[0033] Multi-component transition metal borides containing VB2 (or one of SiB2, GeB2, or MoB2) can be oxidized at 800-900 °C to generate V2O5 (SiO2, GeO2, MoO3) and B2O3. V2O5 (SiO2, GeO2, MoO3), which has a very high amorphous transformation ability, can enter B2O3 (Ta, Ti, Zr, Hf, Zr, Nb, Cr, and W do not have this effect), causing B2O3, which would otherwise leave the substrate surface in gaseous form, to remain on the substrate surface in the form of V(Si, Ge, Mo)-BO amorphous melt glass. This glaze layer not only provides antioxidant and wear resistance, but also significantly reduces the friction coefficient of the transition metal boride ceramic. The resulting multi-component transition metal boride has excellent self-lubricating, anti-wear, and anti-oxidation properties, providing a new solution for improving the high-temperature self-lubrication of transition metal boride ceramics. The treatment method provided by the present invention can significantly reduce the high-temperature friction coefficient and simultaneously optimize the oxidation resistance and wear resistance of the multi-component transition metal boride.

[0034] The following describes the process in conjunction with specific embodiments: Example

[0035] Yes 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4 )B2 quaternary boride ceramics were treated with this process. The specific treatment process is as follows: TaB2, TiB2, ZrB2, and VB2 boride powders were weighed in equal molar ratios and ball-milled in a tungsten carbide jar filled with 1 wt% stearic acid at 300 rpm for 4 hours. The ball-to-powder ratio during ball milling was 2:1. The milled boride powder was then sintered at 2000°C and 35 MPa, followed by rapid cooling.

[0036] The polished boride ceramics were examined by X-ray diffraction (XRD, Bruker D8 ADVANCE, λ = 1.5404 Å); and the polished samples were examined by scanning electron microscopy (SEM, FEI Helios G4CX) to study their microstructure. (Ta 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4) XRD pattern of B2 quaternary boride ceramics is as follows Figure 2 As shown in the figure, it can be seen that a single phase (Ta 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4 )B2 quaternary boride; and according to its SEM image ( Figure 5 ) It can be seen that most areas form a single phase (Ta 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4 )B2 quaternary boride. The SEM and XRD analysis results show that the single phase (Ta 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4 )B2 quaternary boride. The hardness of the boride ceramic was measured using a Vickers hardness tester with a force of 4.9 N applied for 15 seconds. The Vickers hardness was 20.54±1.71 GPa.

[0037] The quaternary boride ceramics obtained above were oxidized in a box-type heat treatment furnace at 800°C for 5 min to obtain the pre-oxidized (Ta 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4 )B2 quaternary boride ceramics.

[0038] The tribological performance testing method of this embodiment is as follows: After pre-oxidation (Ta 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4 The friction and wear properties of B2 quaternary boride ceramics were evaluated using a reciprocating friction and wear tester (HT-1200, China). The Al2O3 ball was used as the counterball, with a load of 10 N, a frequency of 3 Hz, a temperature of 1000 °C, and a run time of 30 min. The wear properties were also measured using a three-dimensional profilometer.

[0039] The average friction coefficient of the quaternary boride ceramic of Example 1 after the friction coefficient stabilizes under a load of 10 N (after 15 minutes) is 0.129. Figure 8 The wear rate of the quaternary boride ceramic of Example 1 under a load of 10 N is 2.80×10 −5 mm 3 / N·m.

[0040] Example 2 Yes 1 / 5 Ti 1 / 5 Zr 1 / 5 V1 / 5 Hf 1 / 5 This process was used to treat 5-element boride ceramics made of 1-element boride (B2). The specific treatment process involved weighing boride powders of TaB2, TiB2, ZrB2, VB2, and HfB2 in equal molar ratios. The powders were then ball-milled for 4 hours at 300 rpm in a tungsten carbide jar containing 1 wt% stearic acid. The ball-to-powder ratio was 2:1. The milled boride powders were then sintered at 2000°C and 35 MPa, followed by rapid cooling.

[0041] The polished boride ceramics were examined by X-ray diffraction (XRD, Bruker D8 ADVANCE, λ = 1.5404 Å); and the polished samples were examined by scanning electron microscopy (SEM, FEI Helios G4CX) to study their microstructure. (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 ) XRD pattern of B2 penta-boride ceramics is as follows Figure 3 As shown in the figure, it can be seen that a single phase (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 )B2 penta-boride; and according to its SEM image ( Figure 6 ) It can be seen that most areas form a single phase (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 )B2 penta-boride. The SEM and XRD analysis results show that the single phase (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 )B2 pentaary boride. The hardness of the boride ceramic was measured using a Vickers hardness tester with a force of 4.9 N applied for 15 seconds. The Vickers hardness was 23.148±1.08 GPa.

[0042] The above-obtained penta-boride ceramics were oxidized at 800°C for 5 min in a box-type heat treatment furnace to obtain the pre-oxidized (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 )B2 pentaary boride ceramics.

[0043] The tribological performance testing method of this embodiment is as follows: After pre-oxidation at 800 °C for 5 min (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 The friction and wear properties of B2 penta-boride ceramics were evaluated using a reciprocating friction and wear tester (HT-1200, China). The Al2O3 ball was used as the counterball, with a load of 10 N, a frequency of 3 Hz, a temperature of 1000 °C, and a run time of 30 min. The wear properties were also measured using a three-dimensional profilometer.

[0044] The average friction coefficient of the five-element boride ceramic of Example 2 after the friction coefficient stabilizes under a load of 10 N (after 15 minutes) is 0.142. Figure 9 The wear rate of the five-element boride ceramic in Example 2 under a load of 10 N is 1.87×10 −5 mm 3 / N·m.

[0045] The FIB-TEM characterization of the pre-oxidized surface of the penta-boride ceramic of Example 2 is as follows: Figure 11 As shown in the figure, the enrichment of V element in the surface friction film was found, confirming the dominant role of V element in this phenomenon.

[0046] Comparative Example 1 Preparation (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 )B2 ternary boride ceramics, the specific treatment system is: TaB 2， TiB 2， ZrB2 boride powders were weighed in equal molar ratios and ball-milled in a tungsten carbide jar containing 1 wt% stearic acid at 300 rpm for 4 hours. The ball-to-powder ratio was 2:1. The milled boride powders were then fired at 2000°C and 35 MPa, followed by rapid cooling to produce ternary boride ceramics.

[0047] The polished ternary boron boride ceramics were examined by X-ray diffraction (XRD, Bruker D8 ADVANCE, λ =1.5404 Å); and the polished samples were examined by scanning electron microscopy (SEM, FEI Helios G4CX) to study their microstructure.

[0048] Income (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 ) XRD pattern of B2 ternary boride ceramics is as follows Figure 1As shown in the figure, it can be seen that a single phase (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 )B2 ternary boride; and according to its SEM image ( Figure 4 ) It can be seen that most areas form a single phase (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 )B2 ternary boride. The SEM and XRD analysis results show that the single phase (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 )B2 ternary boride. The hardness of this boride ceramic was measured using a Vickers hardness tester with a force of 4.9 N applied for 15 seconds. The Vickers hardness was 21.11±0.77 GPa.

[0049] The ternary boride ceramics obtained above were oxidized at 800°C for 5 min in a box-type heat treatment furnace to obtain the pre-oxidized (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 )B2 ternary boride ceramics.

[0050] The tribological performance testing method of this comparative example is as follows: After pre-oxidation (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 The friction and wear properties of B2 ternary boride ceramics were evaluated using a reciprocating friction and wear tester (HT-1200, China). The Al2O3 ball was used as the counterball, with a load of 10 N, a frequency of 3 Hz, a temperature of 1000 °C, and a run time of 30 min. The wear properties were also measured using a three-dimensional profilometer.

[0051] The average friction coefficient of the ternary boride ceramic of Comparative Example 1 after the friction coefficient stabilizes under a load of 10 N (after 15 minutes) is 0.306. Figure 7 The wear rate of the ternary boride ceramic of Example 1 under a load of 10 N is 6.90×10 −5 mm 3 / N·m.

[0052] The FIB-TEM characterization of the pre-oxidized surface of the ternary boride ceramic of Comparative Example 1 is as follows Figure 10 As shown, no amorphous layer was found.

[0053] Table 1 (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 )B2、(Ta 1 / 4 Ti 1 / 4 Zr1 / 4 V 1 / 4 )B2 and (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 )B2 Vickers hardness

[0054] Table 2 (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 )B2、(Ta 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4 )B2 and (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 ) Friction coefficient of B2 at 1000 °C

[0055] Table 3 (Ta 1 / 3 Ti 1 / 3 Zr 1 / 3 )B2、(Ta 1 / 4 Ti 1 / 4 Zr 1 / 4 V 1 / 4 )B2 and (Ta 1 / 5 Ti 1 / 5 Zr 1 / 5 V 1 / 5 Hf 1 / 5 )B2 wear rate at 1000 °C (×10 −5 mm 3 / N·m)

[0056] In summary, the pre-oxidized multi-component transition metal boride containing VB2 (SiB2, GeB2, MoB2) prepared by this invention exhibits lower friction coefficients and wear rates at temperatures between 800°C and 1200°C compared to multi-component transition metal borides without VB2 (SiB2, GeB2, MoB2). This transition metal boride ceramic can be used in the field of high-temperature self-lubricating, wear-resistant materials, exhibiting significantly superior friction and wear performance compared to mono-component boride ceramics without VB2.

[0057] Obviously, those skilled in the art may make various changes and modifications to this technical solution without departing from the spirit and scope of this technical solution. Thus, if these modifications and variations of this technical solution fall within the scope of the claims of this technical solution and their equivalents, this technical solution is intended to include these modifications and variations.

Claims

1. A method for forming an amorphous layer on a multi-component boride ceramic, characterized in that: The steps include: Step 1: ball-milling the transition metal boride ceramic powder and the boride powder capable of forming an amorphous layer in proportion to prepare a boride mixed powder; Step 2: placing the boride mixed powder obtained in step 1 in a mold and heating it to 1800-2000°C for 5-15 minutes for sintering; applying a uniaxial load of 30-50 MPa when the temperature reaches 800-1000°C; cooling it to room temperature after sintering to obtain a crude multi-component transition metal boride ceramic; Step 3: The crude multi-component transition metal boride ceramic product obtained in step 2 after pretreatment is subjected to oxidation treatment to form an amorphous protective layer on the surface of the multi-component transition metal boride ceramic.

2. The method for forming an amorphous layer on a multi-component boride ceramic according to claim 1, wherein: The transition metal boride ceramics are one to four of TaB2, TiB2, ZrB2, HfB2, ZrB2, NbB2, CrB2, and WB2.

3. The method for forming an amorphous layer on a multi-component boride ceramic according to claim 1, wherein: The boride capable of forming an amorphous layer is any one of VB2, SiB2, GeB2, and MoB2.

4. The method for forming an amorphous layer on a multi-component boride ceramic according to claim 1, wherein: The molecular formula of the boride mixed powder prepared in step 1 is (A a B b C c D d E e )B2, where ABCD are different elements selected from Ta, Ti, Zr, Hf, Zr, Nb, Cr or W, E is an element selected from V, Si, Ge or Mo, abcd is 0 to 1 / 2, e is 1 / 5 to 1 / 2, the values of abcd not equal to 0 are equal and equal to e, and a+b+c+d+e=1.

5. The method for forming an amorphous layer on a multi-component boride ceramic according to claim 1, wherein: In step 1, the ball milling process is as follows: the transition metal boride ceramic powder and the boride powder capable of forming an amorphous layer are placed in a tungsten carbide tank filled with 1 wt% stearic acid and ball milled for 4 to 24 hours at a rotation speed of 150 to 360 r / min. The ball-to-powder ratio during the ball milling process is 2 to 5:

1.

6. The method for forming an amorphous layer on a multi-component boride ceramic according to claim 1, wherein: In step 2, the sintering process is as follows: the boride mixed powder obtained in step 1 is loaded into a graphite mold, heated to 1800-2000°C at a heating rate of 80-120°C / min under an argon atmosphere in a spark plasma sintering furnace, kept warm for 5-15 minutes, and when the temperature reaches 800-1000°C, a uniaxial load of 30-50 MPa is applied; finally, the mixture is cooled to room temperature at a cooling rate of 80-120°C / min.

7. The method for forming an amorphous layer on a multi-component boride ceramic according to claim 1, wherein: In step three, the pretreatment process of the multi-component transition metal boride ceramic crude product is as follows: the multi-component transition metal boride ceramic crude product obtained in step two is ground to a grit size of 2000 using a diamond grinding wheel, and then surface polished using a colloidal silica suspension.

8. The method for forming an amorphous layer on a multi-component boride ceramic according to claim 1, wherein: In step three, the oxidation treatment process is: heat treatment in a box-type heat treatment furnace at 800~900 °C for 5~10 minutes.

9. The method for forming an amorphous layer on a multi-component boride ceramic according to claim 1, wherein: In step three, the oxidation treatment process is: surface ablation treatment by oxyacetylene flame for 3-5 minutes.

10. The method for forming an amorphous layer on a multi-component boride ceramic according to claim 1, wherein: In step 3, the thickness of the formed amorphous protective layer is 100-800µm.

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