前驱体法制备(Zr, Hf, Nb, Ta, W)C-SiC复相陶瓷及性能研究

doi:10.15541/jim20240385

摘要/Abstract

摘要：

高熵碳化物(HEC)陶瓷具有硬度高、抗氧化、耐腐蚀、耐磨以及高导热等优点, 在极端环境下具有巨大应用潜力。但高熵陶瓷往往脆性较大, 限制了其进一步应用。为了对HEC陶瓷进行增韧, 本工作在(Zr, Hf, Nb, Ta, W)C高熵陶瓷前驱体中加入碳化硅(SiC)的前驱体聚碳硅烷(PCS), 利用PCS裂解过程中原位生成的SiC(SiC_i)对HEC陶瓷进行增韧。结果表明, 裂解所得陶瓷中SiC的体积分数为23.38%, SiC相晶粒尺寸小(1.19 μm), 且在高熵陶瓷相中均匀分布。通过研究陶瓷前驱体的裂解过程, 发现PCS裂解产物在温度较低时以无定形的O_x-Si-C_y形式存在, 在1500 ℃以上才开始出现SiC结晶相。以1600 ℃裂解所得(Zr, Hf, Nb, Ta, W)C-SiC_i复相陶瓷粉体为原料, 经热压制备了(Zr, Hf, Nb, Ta, W)C-SiC_i陶瓷块体, 研究了陶瓷块体的力学性能, 并与添加商品化SiC纳米粉体及SiC晶须增韧的复相陶瓷进行对比。研究发现, 与(Zr, Hf, Nb, Ta, W)C陶瓷相比, 所有复相陶瓷块体的弯曲强度和断裂韧性均得到明显提升, 其中采用聚合物前驱体法原位生成SiC的增韧效果最为明显, 所得陶瓷的弯曲强度和断裂韧性分别为(698±9) MPa和(7.9±0.6) MPa·m^1/2, 相比(Zr, Hf, Nb, Ta, W)C陶瓷分别提升了17.71%和41.07%。由于液相聚合物前驱体法制备的复相陶瓷中, SiC的晶粒尺寸最小且分布更加均匀, 在受力时可以消耗更多能量, 阻碍裂纹扩展, 因此陶瓷的断裂韧性得到了大幅提高。

关键词: 聚合物前驱体法, 高熵碳化物, 碳化硅, 力学性能

Abstract:

High-entropy carbide (HEC) ceramics are distinguished by their high hardness, oxidation resistance, corrosion resistance, wear resistance, and high thermal conductivity, positioning them as promising candidates for application in extreme environments. However, inherent brittleness of these high-entropy ceramics limits their further application. In order to enhance the toughness of HEC ceramics, polycarbosilane (PCS), a precursor of silicon carbide (SiC), was added into the precursor of (Zr, Hf, Nb, Ta, W)C high-entropy ceramic. The in-situ formed SiC (SiC_i) by pyrolysis of PCS can serve as reinforcement for HEC ceramics. The results demonstrate that the volume fraction of SiC in the ceramics obtained from the pyrolysis of PCS is 23.38%. The SiC phases, with an average grain size of 1.19 μm, are evenly distributed in the high-entropy ceramic matrix. The pyrolysis process of ceramic precursors was investigated, revealing that the pyrolysis products of PCS exit as amorphous O_x-Si-C_y at low pyrolysis temperature, while a crystalline SiC phase emerges when the pyrolysis temperature exceeds 1500 ℃. Bulk (Zr, Hf, Nb, Ta, W)C-SiC_i ceramic was prepared by hot-pressing of precursor-derived ceramic powders obtained through pyrolysis at 1600 ℃. Mechanical properties of (Zr, Hf, Nb, Ta, W)C-SiC_i ceramic bulk were investigated, and composite ceramic bulks toughened by commercial silicon carbide nanopowders or silicon carbide whiskers were also prepared for comparison. Compared with (Zr, Hf, Nb, Ta, W)C ceramic, all composite ceramic bulks exhibit enhanced flexural strength and toughness. Notably, the in-situ generated SiC_i via precursor-derived method shows the most significant toughening effect. Flexural strength and fracture toughness of (Zr, Hf, Nb, Ta, W)C-SiC_i ceramic are (698±9) MPa and (7.9±0.6) MPa·m^1/2, respectively, representing improvements of 17.71% and 41.07% compared to that of (Zr, Hf, Nb, Ta, W)C ceramic bulk. Taking all above data into comprehensive account, the improvement is mainly due to the small grain size and uniform distribution of SiC in the composite ceramics prepared via precursor-derived method, which enhance energy consumption and hinder crack propagation under external stress.

Key words: precursor-derived method, high-entropy carbide, silicon carbide, mechanical property

中图分类号:

TB383

李紫薇, 弓伟露, 崔海峰, 叶丽, 韩伟健, 赵彤. 前驱体法制备(Zr, Hf, Nb, Ta, W)C-SiC复相陶瓷及性能研究[J]. 无机材料学报, 2025, 40(3): 271-280.

LI Ziwei, GONG Weilu, CUI Haifeng, YE Li, HAN Weijian, ZHAO Tong. (Zr, Hf, Nb, Ta, W)C-SiC Composite Ceramics: Preparation via Precursor Route and Properties[J]. Journal of Inorganic Materials, 2025, 40(3): 271-280.

图/表 18

图1 PHEC-PCS固化物的TG-DTG曲线(a)和PHEC-PCS固化物裂解过程气体释放的MS曲线(b~e)

Fig. 1 (a) TG-DTG curves of cured PHEC-PCS and (b-e) MS spectra of gases released during pyrolysis of cured PHEC-PCS

图2 不同温度裂解所得HEC-W5-SiCi样品的XPS图谱

Fig. 2 XPS spectra of HEC-W5-SiCi obtained at different pyrolysis temperatures (a, b) Nb3d and Ta4f of HEC-W5-SiCi-1000; (c, d) Hf4f and W4f of HEC-W5-SiCi-1200; (e, f) Zr3d and Si2p of HEC-W5-SiCi-1400. Colorful figures are available on website

图3 PHEC-PCS在600~1800 ℃裂解所得粉体的XRD图谱

Fig. 3 XRD patterns of PHEC-PCS pyrolyzed in the range of 600-1800 ℃

图4 600~1800 ℃裂解所得HEC-W5-SiCi粉体的SEM照片

Fig. 4 SEM images of HEC-W5-SiCi powder pyrolyzed in the range of 600-1800 ℃

图5 1600 ℃裂解所得HEC-W5-SiCi粉体的SEM照片和EDS图谱

Fig. 5 SEM image and EDS mappings of HEC-W5-SiCi powder pyrolyzed at 1600 ℃

图6 HEC-W5-SiCi(a, d)、HEC-W5-SiCp(b, e)和HEC-W5-SiCw(c, f)复相陶瓷的表面SEM照片(a~c)及其中SiC相的晶粒尺寸(d~f)

Fig. 6 (a-c) Surface SEM images and (d-f) grain size statistics of SiC in (a, d) HEC-W5-SiCi, (b, e) HEC-W5-SiCp, and (c, f) HEC-W5-SiCw bulk ceramics

图7 HEC-W5、HEC-W5-SiCp、HEC-W5-SiCw和HEC-W5-SiCi复相陶瓷的力学性能

Fig. 7 Mechanical properties of HEC-W5, HEC-W5-SiCp, HEC-W5-SiCw, and HEC-W5-SiCi ceramics (a) Vickers hardness; (b) Elasticity modulus; (c) Flexural strength; (d) Fracture toughness

图8 维氏硬度测试后陶瓷的裂纹扩展形貌图

Fig. 8 Morphologies of crack extension of ceramics after Vickers hardness test (a) HEC-W5; (b) HEC-W5-SiCp; (c) HEC-W5-SiCw; (d) HEC-W5-SiCi

图9 HEC-W5-SiCi复相陶瓷的弯曲强度和断裂韧性与文献[11,14,22⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓ -34]数据的对比

Fig. 9 Flexural strength and fracture toughness of HEC-W5- SiCi ceramics of this work and data in literature[11,14,22⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓ -34] *This literature only has fracture toughness data.

表S1 HEC-W5-SiCi-1600样品的元素含量分析

Table S1 Elemental content analysis of HEC-SiCi-1600

Empirical formula	Content/(%, in mass)
Empirical formula	Zr	Hf	Nb	Ta	W	Si	C	O
(Zr_0.238Hf_0.237Nb_0.237Ta_0.237W_0.05)-Si_0.347C_1.405O_0.031	13.1	25.6	13.3	25.9	5.5	5.9	10.2	0.3

表S2 HEC-W5、HEC-W5-SiCp、HEC-W5-SiCw和HEC-W5-SiCi的力学性能

Table S2 Mechanical properties of HEC-W5, HEC-W5-SiCp, HEC-W5-SiCw, and HEC-W5-SiCi ceramics

Sample	Vickers hardness/GPa	Elasticity modulus/GPa	Flexural strength/MPa	Fracture toughness/ (MPa·m^1/2)	Shape factor, Y
HEC-W5	23.82±0.49	447.07±3.71	593±15	5.6±0.2	2.537
HEC-W5-SiC_p	21.79±0.78	418.96±5.24	675±12	7.1±0.5	2.535
HEC-W5-SiC_w	21.61±0.35	435.50±4.38	726±18	6.7±0.3	2.533
HEC-W5-SiC_i	23.03±0.63	575.70±8.25	698±9	7.9±0.6	2.534

表S3 HEC-W5-SiCi复相陶瓷与已报道陶瓷的弯曲强度和断裂韧性数据汇总[11,14,22⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓ -34]

Table S3 Flexural strength and fracture toughness of HEC-W5-SiCi ceramics and previous studies[11,14,22⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓ -34]

Sample	Flexural strength/MPa	Fracture toughness/(MPa·m^1/2)	Ref.
(Ti_0.25Nb_0.25Hf_0.25Ta_0.25)C_0.3N_0.7	481±56^b	7.17±0.62^c	[22]
(TiZrHfVNbTa)C	473±21^b	3.6±0.2^c	[23]
(Hf_0.2Zr_0.2Ta_0.2Nb_0.2Ti_0.2)C	400^b	5.9^c	[24]
(Hf_0.2Zr_0.2Ta_0.2Nb_0.2Ti_0.2)C	450±64^b	4.8±0.2^c	[25]
(Hf_0.2Ta_0.2Zr_0.2Nb_0.2Ti_0.2)C	494^b	2.306^d	[26]
(Hf_0.2Zr_0.2Ti_0.2Ta_0.2Nb_0.2)C	421±27^a	3.5±0.3^d	[27]
(Ti_0.2Hf_0.2Zr_0.2Nb_0.2Ta_0.2)B₂	-	2.83±0.15^e	[28]
(Hf_0.2Nb_0.2Ta_0.2Ti_0.2Zr_0.2)B₂	376±25^b	4.70±0.27^c	[29]
(Ti_0.2Zr_0.2Hf_0.2Nb_0.2Ta_0.2)B₂	339±17^a	3.81±0.40^c	[30]
(Ti_0.2Zr_0.2Hf_0.2Nb_0.2Ta_0.2)B₂-20SiC_p	447±45^a	4.85±0.33^c	[30]
(NbTaZrW)C-50SiC_P	455^b	6.54^c	[31]
(HfZrTaTiW)C-1.5wt%SiC_nw	626.5^b	6.2^e	[32]
(Ti_0.2Zr_0.2Hf_0.2Nb_0.2Ta_0.2)B₂-20SiC_p	750±43^b	4.12±0.20^e	[33]
(Ti_0.2Zr_0.2Hf_0.2Nb_0.2Ta_0.2)B₂-20SiC_p	476±42^b	4.63±0.23^c	[34]
(Ti_0.2Zr_0.2Hf_0.2Nb_0.2Ta_0.2)C-20SiC_p	554±73^a	5.24±0.41^c	[11]
HEC-W5	593±15^b	5.6±0.2^c	[14]
HEC-W5-SiC_p	675±12^b	7.1±0.5^c	This work
HEC-W5-SiC_w	726±18^b	6.7±0.3^c	This work
HEC-W5-SiC_i	698±9^b	7.9±0.6^c	This work

图S1 HEC-W5-SiCi样品的XPS图谱

Fig. S1 XPS spectra of HEC-W5-SiCi (a-d) W4f, Zr3d, Hf4f and Si2p of HEC-W5-SiCi-1000; (e, f) Zr3d and Si2p of HEC-W5-SiCi-1200

图S2 商品化SiCp和SiCw的SEM照片

Fig. S2 SEM images of commercialized SiCp and SiCw

图S3 (a)HEC-W5和HEC-W5-SiC陶瓷的致密度, (b)不同HEC-W5-SiC陶瓷的XRD图谱

Fig. S3 (a) Relative density of HEC-W5 ceramics and HEC-W5-SiC ceramics, (b) XRD patterns of different EC-W5-SiC ceramics

图S4 HEC-W5-SiCp陶瓷表面的SEM照片及EDS面扫描

Fig. S4 SEM image and EDS mappings of HEC-W5-SiCp ceramics surface

图S5 HEC-W5-SiCw陶瓷表面的SEM照片及EDS面扫描

Fig. S5 SEM image and EDS mappings of HEC-W5-SiCw ceramics surface

图S6 HEC-W5-SiCi陶瓷表面的SEM照片及EDS面扫描

Fig. S6 SEM images and EDS mappings of HEC-W5-SiCi ceramics surface

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