Ti3SiC2 ceramic as well as preparation method and application thereof

Abstract

The invention discloses Ti3SiC2 ceramic and a preparation method and application thereof.The preparation method of the Ti3SiC2 ceramic comprises the following steps that based on three-dimensional data of a geometric structure model of a target sample, Ti powder and SiC powder serve as raw materials, and a ceramic precursor is prepared through a layer-by-layer fusion forming technology; the ceramic precursor is subjected to pressureless sintering under the vacuum condition, the pressureless sintering temperature ranges from 1350 DEG C to 1750 DEG C, furnace cooling is carried out after sintering is finished, and the Ti3SiC2 ceramic is prepared. The Ti3SiC2 ceramic with a complex structure is prepared by adopting the SLM and pressureless reaction sintering composite process, the prepared sample is good in geometric integrity and free of obvious macroscopic cracks and other defects, and a new thought and method are provided for preparation of the existing Ti3SiC2 ceramic.

Description

Technical Field

[0001] The present invention belongs to the field of advanced ceramic materials, and in particular relates to a Ti3SiC2 ceramic and a preparation method and application thereof. Background Art

[0002] Ti3SiC2 is a typical representative of ternary layered MAX phase compounds. Its crystal structure has the unique characteristics of alternating stacking of TiC octahedral layers and Si atomic layers. It has the dual characteristics of ceramics and metals, and is characterized by low density, high elastic modulus, excellent mechanical strength, good electrical and thermal conductivity, and outstanding high-temperature oxidation resistance. It shows important application prospects in high-end manufacturing fields such as aerospace and nuclear industry.

[0003] Currently, the fabrication of Ti3SiC2 bulk materials relies primarily on traditional processes such as hot pressing and self-propagating high-temperature synthesis (SHS). While complex components can be produced through subsequent processing, the material's inherent high hardness and brittleness lead to significant tool wear and high processing costs during subtractive machining. In particular, microstructure control and performance optimization remain technical bottlenecks in the fabrication of complex components with internal cavities, lattices, and porous structures. Additive manufacturing, leveraging the layer-by-layer formation principle, can efficiently fabricate functional ceramic components with complex internal cavities, multi-level porosity, or biomimetic topologies. Its near-net-shape properties increase material utilization to over 95%, and it supports multi-material integrated printing (with an accuracy of ±20μm). However, Ti3SiC2 decomposes before its melting point at high temperatures, making it difficult to directly form through conventional melt-solidification processes. Existing technologies utilize a process that combines selective laser sintering (SLM) with reactive sintering: a preform is first prepared through additive manufacturing, followed by reactive sintering to achieve material synthesis. For example, Nan et al. prepared a TiC ceramic preform by adding dextrin as a binder. After liquid silicon infiltration, they obtained a sintered body with a Ti3SiC2 content of 45 vol% by means of a solid-phase reaction between TiC and Si. However, this method requires the introduction of a binder, the Ti3SiC2 content in the product still needs to be improved, and the forming performance of complex structural ceramic components has not been verified. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention aims to provide a Ti3SiC2 ceramic and its preparation method and application, so as to solve the problems of insufficient Ti3SiC2 phase content and difficulty in forming complex structures in the existing technology.

[0005] The purpose of the present invention is achieved through the following technical solutions: A method for preparing Ti3SiC2 ceramics comprises the following steps: Based on the three-dimensional data of the target sample's geometric structure model, a ceramic precursor was prepared using Ti powder and SiC powder as raw materials through a layer-by-layer melt molding process. The ceramic precursor was pressurelessly sintered under vacuum conditions at a temperature of 1350-1750°C. After sintering, the ceramic precursor was cooled in the furnace to obtain Ti3SiC2 ceramics.

[0006] Preferably, the amount of Ti powder to SiC powder is 1:0.5-1.0.

[0007] Preferably, the Ti powder has an average particle size of 15-53 μm, a purity of 99.9%, and a spherical morphology.

[0008] Preferably, the average particle size of the SiC powder is 15 to 50 μm.

[0009] Preferably, the layer-by-layer melting molding process is implemented using a laser powder bed melting device, and the operating parameters of the laser powder bed melting device are: scanning spacing of 10~100μm, layer thickness of 10~100μm, interlayer optical path rotation angle of 67°, and a combination of laser power and scanning speed selected from the following parameter group: 120 W and 800 mm / s, 120 W and 1200 mm / s, 120 W and 1600 mm / s, 180 W and 1200 mm / s, and 240 W and 1200 mm / s.

[0010] Preferably, in the step of pressureless sintering the ceramic precursor under vacuum conditions, the vacuum degree is -80 to -100 KPa.

[0011] Preferably, the specific operation of pressureless sintering the ceramic precursor under vacuum conditions is as follows: heating to 1350-1750° C. at a rate of 2-10° C. / min, and sintering at this temperature for 1-5 hours.

[0012] Preferably, the temperature is raised to 1650° C. at a rate of 5° C. / min and sintered for 2 h.

[0013] The Ti3SiC2 ceramics prepared by the above-mentioned preparation method of Ti3SiC2 ceramics.

[0014] The above-mentioned Ti3SiC2 ceramics are used in the fields of aerospace and nuclear industry.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention uses Ti and SiC powders as raw materials, employing a combined SLM and pressureless reaction sintering process to produce Ti3SiC2 ceramics with complex structures. The resulting samples exhibit excellent geometric integrity, free of defects such as obvious macrocracks. While some pores and irregularly arranged particles still exist in the microstructure, this does not affect their application value in scientific research. This invention provides new ideas and methods for the preparation of existing Ti3SiC2 ceramics. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 These are SEM images of the Ti powder and SiC powder of the present invention, where a corresponds to Ti powder and b corresponds to SiC powder.

[0017] Figure 2 XRD diffraction patterns of the Ti3SiC2 ceramic precursors prepared in Examples 1 to 3.

[0018] Figure 3 XRD diffraction patterns of the Ti3SiC2 ceramic precursors prepared in Examples 2 and 4-5.

[0019] Figure 4 These are SEM images of the Ti3SiC2 ceramic precursor prepared in Example 1 at different magnifications.

[0020] Figure 5 These are SEM images of the Ti3SiC2 ceramic precursor prepared in Example 2 at different magnifications.

[0021] Figure 6 These are SEM images of the Ti3SiC2 ceramic precursor prepared in Example 3 at different magnifications.

[0022] Figure 7 These are SEM images of the Ti3SiC2 ceramic precursor prepared in Example 4 at different magnifications.

[0023] Figure 8 These are SEM images of the Ti3SiC2 ceramic precursor prepared in Example 5 at different magnifications.

[0024] Figure 9 These are actual photos of Ti3SiC2 ceramics prepared in Examples 6 and 7.

[0025] Figure 10 This is the XRD diffraction spectrum of the Ti3SiC2 ceramic prepared in Example 6.

[0026] Figure 11 These are SEM images of the Ti3SiC2 ceramics prepared in Example 6 at different magnifications. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] In the following examples, selective laser melting (SLM) was performed using an EOS M290 machine equipped with a Yb fiber laser. The laser wavelength ranged from 1060 to 1100 nm, with a maximum power of 400 W. The scanning strategy employed a raster reciprocating scan pattern with a scan interval of 50 μm. To ensure build quality, the powder layer thickness was simultaneously controlled at 50 μm.

[0029] Example 1 A method for preparing a Ti3SiC2 ceramic precursor, the specific steps are as follows: The three-dimensional data of the target sample geometric structure (cube, size 10 mm × 10 mm × 10 mm) model were designed. Ti powder and SiC powder were used as raw materials and a ceramic precursor was prepared by layer-by-layer melting and molding using a laser powder bed fusion equipment. The operating parameters of the laser powder bed fusion equipment were as follows: laser power of 120 W, scanning spacing of 50 μm, layer thickness of 50 μm, scanning speed of 800 mm / s, and interlayer optical path rotation angle of 67°. The ceramic precursor was heated to 1650°C at a rate of 5°C / min, sintered under pressureless conditions for 2 h, and then cooled to room temperature with the furnace to prepare Ti3SiC2 ceramics.

[0030] Example 2 Example 2 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the difference is that the laser power is 120 W and the scanning speed is 1200 mm / s.

[0031] Example 3 Example 2 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the difference is that the laser power is 120 W and the scanning speed is 1600 mm / s.

[0032] Example 4 Example 4 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the difference is that the laser power is 180 W and the scanning speed is 1200 mm / s.

[0033] Example 5 Example 4 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 240 W and the scanning speed is 1200 mm / s.

[0034] Comparative Examples 1 to 5 Comparative Examples 1 to 5 provide a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the scanning speed is fixed at 400 mm / s, and the laser power is set to 120 W, 180 W, 240 W, 300 W and 360 W, respectively.

[0035] Comparative Examples 6-10 Comparative Examples 6 to 10 provide a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the scanning speed is fixed at 600 mm / s, and the laser power is set to 120 W, 180 W, 240 W, 300 W and 360 W, respectively.

[0036] Comparative Example 11 Comparative Example 11 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 180 W and the scanning speed is 800 mm / s.

[0037] Comparative Example 12 Comparative Example 12 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 240 W and the scanning speed is 800 mm / s.

[0038] Comparative Example 13 Comparative Example 13 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 300 W and the scanning speed is 800 mm / s.

[0039] Comparative Example 14 Comparative Example 14 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 360 W and the scanning speed is 800 mm / s.

[0040] Comparative Examples 15-19 Comparative Examples 15 to 19 provide a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the scanning speed is fixed at 1000 mm / s, and the laser power is set to 120 W, 180 W, 240 W, 300 W and 360 W, respectively.

[0041] Comparative Example 20 Comparative Example 20 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 300 W and the scanning speed is 1200 mm / s.

[0042] Comparative Example 21 Comparative Example 21 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 360 W and the scanning speed is 1200 mm / s.

[0043] Comparative Examples 22-26 Comparative Examples 22 to 26 provide a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the scanning speed is fixed at 1400 mm / s, and the laser power is set to 120 W, 180 W, 240 W, 300 W and 360 W, respectively.

[0044] Comparative Example 27 Comparative Example 21 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 180 W and the scanning speed is 1600 mm / s.

[0045] Comparative Example 28 Comparative Example 21 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 240 W and the scanning speed is 1600 mm / s.

[0046] Comparative Example 29 Comparative Example 21 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 300 W and the scanning speed is 1600 mm / s.

[0047] Comparative Example 30 Comparative Example 21 provides a method for preparing a Ti3SiC2 ceramic precursor. Compared with Example 1, the differences are: the laser power is 360 W and the scanning speed is 1600 mm / s.

[0048] By observing the appearance of the ceramic precursors prepared in Examples 1 to 5 and Comparative Examples 1 to 30, it can be found that the samples of Comparative Examples 1 to 30 have serious surface defects and cannot be used to prepare products with complex shapes; in contrast, the samples of Examples 1 to 5 have significantly fewer surface defects and fully meet the molding requirements of complex structural parts.

[0049] Example 6 A preparation method of Ti3SiC2 ceramics, the specific steps are as follows: (1) Design the three-dimensional data of the target sample's geometric structure model. The specific geometric structure is a cuboid with dimensions of 30 mm × 10 mm × 6 mm. (2) Ti powder and SiC powder were used as raw materials and a ceramic precursor was prepared by layer-by-layer melting and molding using a laser powder bed fusion device. The operating parameters of the laser powder bed fusion device were as follows: laser power of 240 W, scanning spacing of 50 μm, layer thickness of 50 μm, scanning speed of 1200 mm / s, and interlayer optical path rotation angle of 67°. The ceramic precursor was heated to 1650℃ at a rate of 5℃ / min and sintered under vacuum (vacuum degree of -0.1 MPa) for 2 h without pressure. It was then cooled to room temperature in the furnace to obtain Ti3SiC2 ceramics. XRD test and semi-quantitative analysis of the diffraction data using Jade software showed that the mass fraction of the Ti3SiC2 phase in the prepared Ti3SiC2 ceramics was 65%.

[0050] Implementation 7 A preparation method of Ti3SiC2 ceramics, the specific steps are as follows: (1) Design the three-dimensional data of the target sample geometric structure model. The specific geometric structure is a cube unit porous structure with an overall size of 20 mm × 18 mm × 10 mm; the wall thickness of the cube unit is 2 mm, and the size is 2 mm × 2 mm × 2 mm.

[0051] (2) Ti powder and SiC powder were used as raw materials and a ceramic precursor was prepared by layer-by-layer melting and molding using a laser powder bed fusion device. The operating parameters of the laser powder bed fusion device were as follows: laser power of 240 W, scanning spacing of 50 μm, layer thickness of 50 μm, scanning speed of 1200 mm / s, and interlayer optical path rotation angle of 67°. The ceramic precursor was heated to 1650°C at a rate of 5°C / min and sintered under vacuum (vacuum degree of -0.1 MPa) without pressure for 2 h. It was then cooled to room temperature in the furnace to obtain Ti3SiC2 ceramics. XRD test and semi-quantitative analysis of the diffraction data using Jade software showed that the mass fraction of the Ti3SiC2 phase in the prepared Ti3SiC2 ceramics was 78%.

[0052] Figure 1 is the SEM picture of the Ti powder and SiC powder of the present invention, as shown in Figure 1 As shown in the figure, Ti powder particles have a nearly spherical structure, while SiC powder exhibits an irregular polygonal morphology. This morphological difference is closely related to their respective crystal growth mechanisms.

[0053] Figure 2 The XRD diffraction patterns of the Ti3SiC2 ceramic precursors prepared in Examples 1 to 3 are as follows: Figure 2As shown, the XRD diffraction spectra all show obvious characteristic peaks of TiSi2, Ti5Si3, TiC and Ti3SiC2, and the incompletely reacted 6H-SiC residual phase can be detected. Figure 2 Semi-quantitative analysis of the various phases revealed that, at a scanning power of 120 W, as the scanning speed decreased from 1600 mm / s to 800 mm / s, the relative content of TiC increased monotonically, while the mass fraction of Ti3SiC2 decreased by 7.5%. The changes in the contents of SiC, TiSi2, and Ti5Si3 did not show any significant regularity. This phase evolution is primarily due to the in-situ reaction of Ti with SiC during the SLM process to form TiC, simultaneously releasing free Si. This is due to the large reaction enthalpy change and low Gibbs free energy of the TiC synthesis reaction. Furthermore, Si and Ti further react to primarily form TiSi2. As the Ti content gradually decreases, once its concentration reaches a certain threshold, another compound, Ti5Si3, begins to increase.

[0054] Figure 3 The XRD diffraction patterns of the Ti3SiC2 ceramic precursors prepared in Examples 2 and 4-5 are as follows: Figure 3 As mentioned, Figure 3 Semi-quantitative analysis of the different phases in the reaction product showed that the mass ratios of TiC, TiSi2, and Ti3SiC2 increased with increasing laser power, while the mass ratios of Ti5Si3 and SiC decreased. Specifically, when the laser power increased from 120 W to 240 W, the mass ratio of TiC increased by 7.2%, and the mass ratio of Ti3SiC2 increased by 6.5%. Under all experimental conditions, a small amount of Ti3SiC2 phase was detected in the reaction product. The orderly growth of Ti3SiC2 crystals is a slow kinetic process controlled by diffusion. During rapid cooling, excessively high cooling rates "freeze" unreacted intermediate phases, making it difficult to form high levels of Ti3SiC2 in the material.

[0055] Figures 4 to 8 The SEM images of the Ti3SiC2 ceramic precursors prepared in Examples 1 to 5 at different magnifications are shown in FIG. Figures 4 to 8As shown in the figure, SEM analysis of the polished surface of the sample prepared using SLM technology reveals a large number of tiny holes on the surface of the sample, with poor overall continuity. In addition, many irregularly shaped pits are visible on the surface. These defects significantly reduce the degree of material densification. With the increase of laser power and the decrease of scanning speed, the number of existing holes increases significantly and gradually penetrates each other, eventually forming defects similar to "long rivers". The image also contains many cracks, whose sizes are mainly distributed in the range of tens to hundreds of microns. These pores and cracks may be caused by incomplete gas escape or localized material shrinkage during melting and solidification, which adversely affects the mechanical properties of the material, such as strength and toughness.

[0056] Figure 9 The following are photos of Ti3SiC2 ceramics prepared in Examples 6 and 7. The sample on the left corresponds to Example 6, and the sample on the right corresponds to Example 7. Figure 9 As shown, the forming process of the present invention has the ability to prepare both basic geometric bodies and complex structures: it can prepare standard rectangular specimens with simple structures, and can also form complex components with porous structures. The prepared samples have good geometric integrity and are free of defects such as obvious macro cracks.

[0057] Figure 10 The XRD diffraction pattern of the Ti3SiC2 ceramic prepared in Example 6 is as follows: Figure 10 As shown in Figure 2, a strong diffraction peak of Ti3SiC2 is observed at 2θ=39.549°, while the characteristic peaks of SiC and TiSi2 are weaker. This is due to the reactive synthesis of Ti3SiC2 due to the low Ti content in the raw materials.

[0058] Figure 11 The SEM images of the Ti3SiC2 ceramics prepared in Example 6 at different magnifications are as follows: Figure 11 As shown in Figure 3, the microstructure of the sintered sample still contains some pores and irregularly arranged particles.

[0059] Combine Figures 9-11 We can see that the present invention uses a composite SLM / pressureless reaction sintering process to prepare Ti3SiC2 samples. This study shows that the performance of sintered Ti3SiC2 samples is largely dependent on the process parameters of selective laser melting (SLM). The splitting ratio and process parameters will be optimized in the future.

[0060] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing Ti3SiC2 ceramics, characterized in that: The steps include: Based on the three-dimensional data of the target sample's geometric structure model, a ceramic precursor was prepared using Ti powder and SiC powder as raw materials through a layer-by-layer melt molding process. The ceramic precursor was pressurelessly sintered under vacuum conditions at a temperature of 1350-1750°C. After sintering, the ceramic precursor was cooled in the furnace to obtain Ti3SiC2 ceramics.

2. The method for preparing Ti3SiC2 ceramics according to claim 1, characterized in that: The layer-by-layer melting molding process is implemented using a laser powder bed melting device. The operating parameters of the laser powder bed melting device are: scanning spacing of 10-100 μm, layer thickness of 10-100 μm, interlayer optical path rotation angle of 67°, and a combination of laser power and scanning speed selected from the following parameter group: 120 W and 800 mm / s, 120 W and 1200 mm / s, 120 W and 1600 mm / s, 180 W and 1200 mm / s, and 240 W and 1200 mm / s.

3. The method for preparing Ti3SiC2 ceramics according to claim 1, characterized in that: The amount of the Ti powder and the SiC powder is 1:0.5-1.

0.

4. The method for preparing Ti3SiC2 ceramics according to claim 3, characterized in that: The Ti powder has an average particle size of 15-53 μm, a purity of 99.9%, and a spherical morphology.

5. The method for preparing Ti3SiC2 ceramics according to claim 4, characterized in that: The average particle size of the SiC powder is 15-50 μm.

6. The method for preparing Ti3SiC2 ceramics according to claim 1, characterized in that: In the step of pressureless sintering of the ceramic precursor under vacuum conditions, the vacuum degree is -80 to -100 KPa.

7. The method for preparing Ti3SiC2 ceramics according to claim 6, characterized in that: The specific operation of pressureless sintering of the ceramic precursor under vacuum conditions is as follows: heating to 1350-1750° C. at a rate of 2-10° C. / min, and sintering at this temperature for 1-5 hours.

8. The method for preparing Ti3SiC2 ceramics according to claim 7, characterized in that: The temperature was raised to 1650°C at a rate of 5°C / min and sintered for 2 h.

9. The Ti3SiC2 ceramic prepared by the method for preparing the Ti3SiC2 ceramic according to any one of claims 1 to 8.

10. Application of the Ti3SiC2 ceramics according to claim 9 in the fields of aerospace and nuclear industry.

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