scholarly journals Preparation and properties of B4C-TiB2 ceramics prepared by spark plasma sintering

2020 ◽  
Author(s):  
Jingzhe Fan ◽  
Weixia Shen ◽  
zhuangfei Zhang ◽  
Chao Fang ◽  
Yuewen Zhang ◽  
...  

Abstract By doping titanium hydride (TiH2) into boron carbide (B4C), a series of B4C + x wt% TiH2 (x = 0, 5, 10, 15 and 20) composite ceramics were obtained through spark plasma sintering (SPS). The effects of sintering temperature and the amount of TiH2 additive on the microstructure, mechanical and electrical properties of the sintered B4C-TiB2 composite ceramics were investigated. Powder mixtures of B4C with 0−20 wt% TiH2 were heated from 1400 to 1800 °C for 20 minutes under 50 MPa. The results indicated that higher sintering temperatures contributed to greater ceramic density. With increasing TiH2 content, titanium diboride (TiB2) formed between the TiH2 and B4C matrix. This effectively improved Young’s modulus and fracture toughness of the composite ceramics, significantly improving their electrical properties: the electrical conductivity reached 114.9 S·cm−1 at 1800 °C when x = 20. Optimum mechanical properties were obtained for the B4C ceramics sintered with 20 wt% TiH2, which had a relative density of 99.9 ± 0.1%, Vickers hardness of 31.8 GPa and fracture toughness of 8.5 MPa·m1/2. The results indicated that the doping of fine Ti particles into the B4C matrix increased the conductivity and the fracture toughness of B4C.

2005 ◽  
Vol 287 ◽  
pp. 335-339 ◽  
Author(s):  
Kyeong Sik Cho ◽  
Kwang Soon Lee

Rapid densification of the SiC-10, 20, 30, 40wt% TiC powder with Al, B and C additives was carried out by spark plasma sintering (SPS). In the present SPS process, the heating rate and applied pressure were kept at 100°C/min and at 40 MPa, while the sintering temperature varied from 1600-1800°C in an argon atmosphere. The full density of SiC-TiC composites was achieved at a temperature above 1800°C by spark plasma sintering. The 3C phase of SiC in the composites was transformed to 6H and 4H by increasing the process temperature and the TiC content. By tailoring the microstructure of the spark-plasma-sintered SiC-TiC composites, their toughness could be maintained without a notable reduction in strength. The strength of 720 MPa and the fracture toughness of 6.3 MPa·m1/2 were obtained in the SiC-40wt% TiC composite prepared at 1800°C for 20 min.


2014 ◽  
Vol 616 ◽  
pp. 194-198 ◽  
Author(s):  
Jian Feng Zhang ◽  
Rong Tu ◽  
Takashi Goto

WC-Co-cBN composites were consolidated by SPS at 1373 to 1673 K under a moderate pressure of 100 MPa. The addition of cBN increased the starting and finishing temperature of shrinkage and decreased the relative density of WC-Co. The relative density of WC-(10-20 vol%) cBN composites was about 97-100% at 1573 K and decreased with increasing the sintering temperature to 1673 K due to the phase transformation of cBN to hBN. The highest hardness and fracture toughness of WC-Co-20 vol% cBN composite sintered at 1573 K were 23.2 GPa and 8.0 MP m1/2, respectively.


2006 ◽  
Vol 313 ◽  
pp. 105-108 ◽  
Author(s):  
Lian Meng Zhang ◽  
Mei Juan Li ◽  
Qiang Shen ◽  
T. Li ◽  
M.Q. Yu

Aluminum nitride-boron nitride (AlN/BN) composite ceramics were prepared by spark plasma sintering (SPS). The sintering behaviors of AlN/BN composites with 5~15% volume fraction of BN were studied. The influences of BN content, as well as the sintering temperature on the density, microstructure, mechanical strength, thermal conductivity and machinability of the composites were also investigated. The results showed that the full densification of AlN/BN composite ceramics could be realized by SPS technique at the temperature no higher than 1800°C for 3 minutes. The thermal conductivity of AlN/BN composites is in the range of 66~79W/mK, and AlN/BN composites can be cut or drilled by carbides or even steel tools when BN content is 15% volume fraction. The mechanical strength of AlN/BN composites is about 330MPa and is not remarkably affected by the addition of BN. The improvement of mechanical properties of AlN/BN composite ceramics is due to the fine and homogenous microstructure developed in the SPS process.


2010 ◽  
Vol 654-656 ◽  
pp. 2158-2161 ◽  
Author(s):  
Eri Miura-Fujiwara ◽  
Takeshi Teramoto ◽  
Hisashi Sato ◽  
Equo Kobayashi ◽  
Yoshimi Watanabe

This study aims at producing porous Ti filled with biodegradable materials for biomedical implants by means of spark plasma sintering method (SPS). To improve bone fixation and to obtain appropriate Young’s modulus as a medical implant material, we applied -tri calcium phosphate (-TCP) to the Ti-based composite. Ti/-TCP powder mixtures were sintered by SPS under applied stress of 45MPa with various temperatures and holding time. Vickers hardness (Hv) of obtained composite increased with increasing the holding time up to 10 min, and saturated hardness was approximately 750 Hv, which is extremely higher than that of bulk Ti. Hardness also increased as sintering temperature increased up to 1473 K. From the results of microstructure observations by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDXS), O- and P- containing Ti surrounded around Ti particle, and O diffused into Ti particle to a certain extent. X-ray diffraction results indicated several kinds of Ti-O and/or Ti-P formed in the specimen. Results indicated that it is the brittle phases formed during sintering that increased the hardness.


2020 ◽  
Author(s):  
Xingheng Yan ◽  
Xingui Zhou ◽  
Honglei Wang

Abstract B4C-TiB2 composite ceramics with ultra-high fracture toughness were successfully prepared via spark plasma sintering at 1900℃ using B4C and Ti3SiC2 as raw materials. The results show that compared with pure B4C ceramics sintered by SPS, the hardness of B4C-TiB2 composite ceramics is decreased, but the flexural strength and fracture toughness are significantly improved, especially the fracture toughness has been improved by leaps and bounds. When the content of Ti3SiC2 is 30vol.%, the B4C-TiB2 composite ceramic has the best comprehensive mechanical properties: hardness, bending strength and fracture toughness are 27.28 GPa, 405.11 MPa and 18.94 MPa·m1/2, respectively. The fracture mode of the B4C-TiB2 composite ceramics is a mixture of transgranular fracture and intergranular fracture. Two main two reasons for the ultra-high fracture toughness are the existence of lamellar graphite at the grain boundary, and the formation of a three-dimensional interpenetrating network covering the whole composite.


2020 ◽  
Author(s):  
Xingheng Yan ◽  
Xingui Zhou ◽  
Honglei Wang

Abstract B4C-TiB2 composite ceramics with ultra-high fracture toughness were successfully prepared via spark plasma sintering using B4C and 30 vol.% Ti3SiC2 as raw materials at different sintering temperatures. The results show that compared with pure B4C ceramics sintered by SPS, the flexural strength and fracture toughness are significantly improved, especially the fracture toughness has been improved by leaps and bounds. When the sintering temperature is 1900 ℃, the B4C-TiB2 composite ceramic has the best comprehensive mechanical properties: hardness, bending strength and fracture toughness are 27.28 GPa, 405.11 MPa and 18.94 MPa·m1/2, respectively. The main two reasons for the ultra-high fracture toughness are the formation of TiB2 three-dimensional network covering the whole composites, and the existence of lamellar graphite at the grain boundary.


2007 ◽  
Vol 534-536 ◽  
pp. 893-896 ◽  
Author(s):  
Swapan Kumar Sarkar ◽  
Min Ho Youn ◽  
Ik Hyun Oh ◽  
Byong Taek Lee

Carbon nanotube (CNT) reinforced hydroxyapatite (HAp) composites were fabricated by using the spark plasma sintering process with surfactant modified CNT and HAp nano powder. Without the dependency on sintering temperature, the main crystal phase existed with the HAp phase although a few contents of β-TCP (Tri calcium phosphate) phase were detected. The maximum fracture toughness, (1.27 MPa.m1/2) was obtained in the sample sintered at 1100 oC and on the fracture surface a typical intergranular fracture mode, as well as the pull-out pmhenomenon of CNT, was observed.


Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 29
Author(s):  
Shi Tian ◽  
Zelin Liao ◽  
Wenchao Guo ◽  
Qianglong He ◽  
Heng Wang ◽  
...  

TiB2-BN composite ceramics combine excellent electrical conductivity, thermal shock resistance, high-temperature resistance, corrosion resistance, and easy processing of TiB2 and BN. However, in practical applications, their high-temperature oxidation resistance is poor and the resistivity distribution is uneven and changes substantially with temperature. A TiB2-BN-SiC composite ceramic with stable and controllable resistivity was prepared by introducing SiC into the TiB2-BN composite ceramics. In this work, spark plasma sintering (SPS) technology was used to prepare TiB2-BN-SiC composite ceramics with various TiB2-SiC ratios and sintering temperatures. The samples were tested by XRD, SEM, and thermal and mechanical analysis. The results show that as the volume ratio of TiB2-SiC was increased from 3:1 to 12:1, the resistivity of the sample decreased from 8053.3 to 4923.3 μΩ·cm, the thermal conductivity increased from 24.89 to 34.15 W/(m k), and the thermal expansion rate increased from 7.49 (10−6/K) to 10.81 (10−6/K). As the sintering temperature was increased from 1650 to 1950 °C, the density of the sample increased, the mechanical properties were slightly improved, and the resistivity, thermal expansion rate, and thermal conductivity changed substantially. The volume ratio and sintering temperature are the key factors that control the resistivity and thermal characteristics of TiB2-SiC-BN composite ceramics, and the in situ from liquid phases of FeB and FeO also promotes the sintering of the TiB2-BN-SiC ceramics.


Sign in / Sign up

Export Citation Format

Share Document