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1.
WuBian Tian Hideki KitaHideki Hyuga Naoki Kondo 《Journal of Alloys and Compounds》2011,509(5):1819-1823
TiB2-C preforms formed with different compositions and processing parameters were reactively infiltrated by Si melts at 1450 °C to fabricate TiB2-SiC-Si composites. Phase constituent and microstructure of these composites were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The resulting composites are generally composed of TiB2 and reaction-formed β-SiC major phases, together with a quantity of residual Si. Unreacted carbon is detected in the samples with a starting composition of 2TiB2 + 1C formed at higher pressure and in all of the ones at the composition of 1TiB2 + 1C. The distribution of these phases is fairly homogeneous in microstructure. TiB2-SiC-Si composites show good mechanical properties, with representative values of 19.9 GPa in hardness, 395 GPa in elastic modulus, 3.5 MPa m1/2 in fracture toughness and 604 MPa in bending strength. The primary toughening and strengthening mechanism is attributed to the crack deflection of TiB2 particles. 相似文献
2.
Effects of sintering additives on microstructure and mechanical properties of TiB2-WC ceramic-metal composite tool materials 总被引:1,自引:0,他引:1
Jinpeng SongChuanzhen Huang Bin ZouHanlian Liu Lin LiuJun Wang 《International Journal of Refractory Metals and Hard Materials》2012,30(1):91-95
TiB2-WC ceramic-metal composite tool materials were fabricated using Co, Ni and (Ni, Mo) as sintering additives by vacuum hot-pressing technique. The microstructure and mechanical properties of the composite were investigated. The composite was analyzed by the observations of scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). The microstructure of TiB2-WC ceramic-metal composites consisted of the fine WC grains and uniform TiB2 grains. The brittle phase of Ni3B4 and a few pores were found in TiB2-WC-Ni ceramic-metal composite. A lot of pores and brittle phases such as W2CoB2 and Co2B were formed in TiB2-WC-Co ceramic-metal composite. The liquid phase of Co was consumed by the reaction which led to the formation of the pores and the coarse grains of TiB2. The pores, brittle phases and coarse grains of TiB2 were harmful to the improvement of the mechanical properties of the composite. The sintering additive of (Ni, Mo) had a significant effect on the density and the mechanical properties of TiB2-WC ceramic-metal composite. The formation of intermetallic compound of MoNi4 inhibited the consumption of liquid phase of (Ni, Mo). The liquid phase of (Ni, Mo) not only inhibited the formation of the pores and the coarse grains of TiB2 but also strengthened the interface energy between WC and TiB2 grains. The grain size was fine and the average relative density of TiB2-WC-(Ni, Mo) ceramic-metal composite reached 99.1%. The flexural strength, fracture toughness and Vickers hardness of TiB2-WC-(Ni, Mo) ceramic-metal composite were 1307.0 ± 121.4 MPa, 8.19 ± 0.29 MPa m1/2 and 22.71 ± 0.82 GPa, respectively. 相似文献
3.
Y. Wang X.M. Qiu D.Q. SunS.Q. Yin 《International Journal of Refractory Metals and Hard Materials》2011,29(2):293-297
The c-BN grain has been brazed with Cu-Ni-Sn-Ti filler metal in vacuum at 1373 K holding for 600 s. The microstructure of the interface between c-BN grain and Cu-Ni-Sn-Ti filler metal has been studied using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS). The composition of the interface has been analyzed by X-ray diffraction analyzer (XRD). Experimental results showed that the reaction layer appeared at the interface between the c-BN grain and the filler metal. The reaction layer mainly consisted of TiN, TiB and TiB2. And the thickness of the reaction layer increases with the increase of Ti content in the filler metal. When Ti content in the filler metal exceeds 15 wt.%, microcracks form at c-BN side of the interface because of the increase of TiN, CuTi and Cu3Ti2 brittle phases and residual stresses, leading to a decrease of the tensile strength of c-BN/Cu-Ni-Sn-Ti composites. Ti content in the filler metal had obvious influence on microstructure and strength of c-BN/ Cu-Ni-Sn-Ti composites. The maximum tensile strength reached 105.1 MPa with 10 wt.% Ti content in the filler metal. 相似文献
4.
Composition, structure and properties of the products of self-propagating high-temperature synthesis (SHS) are characterised by some distinctive features. High heating rate, fast cooling after rapid completion of the reactions and steep temperature gradients make SHS very effective in producing in situ composites with ceramic reinforcements. In the present work, hardfacing of AISI304 substrates has been done by fabricating a hard ternary ceramic matrix composite layer of Al2O3–TiB2–TiN by laser surface treatment at different scan speeds. The formation of the surface layer is due to laser-triggered SHS followed by laser melting. A mixture of Al, TiO2 and hBN has been used as a precursor for the SHS reaction. The study of the microstructure of the as-fabricated composite layer reveals the co-existence of TiB2 and TiN phases in the nanometric size range in Al2O3 matrix. The presence of all the phases has been confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The average grain sizes were calculated for the reinforcing phases and found to be 36 and 66?nm for TiB2 and TiN, respectively, for the ceramic layer fabricated with a scan speed of 10?mm?s?1, whereas 21 and 53?nm have been observed for TiB2 and TiN, respectively, for the ceramic layer fabricated with the scan speed of 5?mm?s?1. The understanding of the chemical synthesis in the SHS reaction mentioned here and the process of development of the reinforced composite in the fabrication of the hardfaced layer over steel surface will be immensely helpful in the discernment of the mechanical properties and, thus, finding the target area for the usage of this product. The virtues of the process and formation of the hard composite are reflected well in the microhardness achieved in the fabricated layers, as it is significantly higher than that of the substrate (AISI304 steel). In addition, indentation with a Berkovich tip in a nano-indentation set-up helped in further evaluation of the composite’s hardness and elastic modulus. The property spectrum of the composite, as reported here, indicates its suitability in various wear-intensive applications. 相似文献
5.
Jianing LiChuanzhong Chen Zhaoqing LinTiziano Squartini 《Journal of Alloys and Compounds》2011,509(14):4882-4886
Laser cladding of the Fe3Al + TiB2/Al2O3 pre-placed alloy powder on Ti-6Al-4V alloy can form the Ti3Al/Fe3Al + TiB2/Al2O3 ceramic layer, which can greatly increase wear resistance of titanium alloy. In this study, the Ti3Al/Fe3Al + TiB2/Al2O3 ceramic layer has been researched by means of electron probe, X-ray diffraction, scanning electron microscope and micro-analyzer. In cladding process, Al2O3 can react with TiB2 leading to formation of amount of Ti3Al and B. This principle can be used to improve the Fe3Al + TiB2 laser cladded coating, it was found that with addition of Al2O3, the microstructure performance and micro-hardness of the coating was obviously improved due to the action of the Al-Ti-B system and hard phases. 相似文献
6.
Xiangbo ShenZhaohui Zhang Sai WeiFuchi Wang Shukui Lee 《Journal of Alloys and Compounds》2011,509(29):7692-7696
In situ synthesized TiB reinforced titanium matrix composites have been synthesized by spark plasma sintering (SPS) process at 950-1250 °C, using mixtures of 15 wt% TiB2 and 85 wt% Ti powders. The effects of the sintering temperature on densification behavior and mechanical properties of the TiB-Ti composites were investigated. The results indicated that with rising sintering temperatures, relative densities of the composites increase obviously, while the in situ TiB whiskers grow rapidly. As a result, bending strength of the TiB-Ti composites increases slowly at the combined actions of the factors referred above. Fracture toughness of the composites is improved remarkably due to the large volume fraction of Ti matrix, the crack deflection, pull-out and the micro-fracture of the needle-shaped TiB grains. The results also suggested that TiB-Ti composite sintered at 1250 °C by SPS process exhibits the highest relative density of 99.6% along with bending strength of 1161 MPa and fracture toughness of 13.5 MPa m1/2. 相似文献
7.
Ming He Shuren ZhangXiaohua Zhou Bo LiJing Wan 《Journal of Alloys and Compounds》2011,509(11):4260-4263
The behavior of dielectric and microwave properties against sintering temperature has been carried out on CaO-SiO2-B2O3 ceramic matrix composites with ZrO2 addition. The results indicated that ZrO2 addition was advantageous to improve the dielectric and microwave properties. X-ray diffraction (XRD) patterns show that the major crystalline β-CaSiO3 and a little SiO2 phase existed at the temperature ranging from 950 °C to 1050 °C. At 0.5 wt% ZrO2, CaO-SiO2-B2O3 ceramic matrix composites sintered at 1000 °C possess good dielectric properties: ?r = 5.85, tan δ = 1.59 × 10−4 (1 MHz) and excellent microwave properties: ?r = 5.52, Q · f = 28,487 GHz (11.11 GHz). The permittivity of Zr-doped CaO-SiO2-B2O3 ceramic matrix composites exhibited very little temperature dependence, which was less than ±2% over the temperature range of −50 to 150 °C. Moreover, the ZrO2-doped CaO-SiO2-B2O3 ceramic matrix composites have low permittivity below 5.5 over a wide frequency range from 20 Hz to 1 MHz. 相似文献
8.
Wenmao Huang Cong ZhouBin Liu Mingliang WangHaowei Wang Naiheng Ma 《Surface & coatings technology》2012
This study reported a novel treatment to improve the corrosion resistance of TiB2/A356 composites. The method was employed in combination of the molten-salt electrodeposition and subsequent electrochemical anodization technique. By means of molten-salt electrodeposition, the Al coatings were deposited on the surface of TiB2/A356 composites. It was found that the morphology of the Al coatings is closely related to the current density. Thus, under the suitable condition, a dense and uniform Al coating can be obtained, with the crystal size in the range of 0.5–2 μm and the coating thickness of ~ 9 μm. This continuous Al layer can eliminate the adverse corrosion contribution of TiB2 particles in Al matrix. The following step of anodization was designed to convert the Al film to an anodized Al oxide film for further corrosion protection. The electrochemical corrosion behavior was evaluated by potentiodynamic polarization curves and electrochemical impedance spectroscopy. These results showed the corrosion resistance was greatly enhanced in TiB2/A356 composites with an anodized Al-coating than that of the anodized composites. It is evident that the new treatment of metal electrodeposition in molten salts and following anodization is an effective method of anti-corrosion in composites. 相似文献
9.
The effect of different sintering additives on the high temperature oxidation and corrosion behaviour of silicon nitride based ceramics was investigated. Comparative tests were conducted at 1200 and 1500 °C in air, in water vapour, and with the highly corrosive gases HCl and SO2. Si3N4 was prepared with MgO, Al2O3, Y2O3 and Al2O3 + Y2O3 sintering additives. Hot pressed discs were tested for a total time of up to 128 h. The electrically conductive ceramic composites Si3N4 + TiN and Si3N4 + MoSi2 were also tested under the same conditions. The effects that the different corrosion environments have on the different ceramics are presented. SEM studies of the oxidised ceramics show the direct transformation of Si3N4 grains into SiO2 through a reaction interface layer. 相似文献
10.
Hongbo LiYongting Zheng Jiecai HanLijuan Zhou 《Journal of Alloys and Compounds》2011,509(5):1661-1664
h-BN-SiC-AlN-TiN ceramic composites with volume content of AlN-TiN ranging from 20% to 70% were prepared by combustion synthesis from powder compacts of B4C, Si, Al and TiN under 100 MPa nitrogen pressure. The volume fraction of AlN-TiN was found to have a significant influence on the microstructure, mechanical properties and thermal shock resistance of the composites. With the increasing volume content of AlN-TiN, the mechanical properties of the composites were improved remarkably, while thermal shock resistance decreased. Thermal shock tests showed that the critical thermal shock temperature (ΔT) was higher than 1200 °C for the composites with AlN-TiN contents of 30 vol%; while it was decreased to 850 and 670 °C for the composites with AlN-TiN contents of 50 and 70 vol%, respectively. 相似文献
11.
Zhiwei Liu Qingyou Han Jianguo LiWeidong Huang 《Journal of Materials Processing Technology》2012,212(2):365-371
Some issues such as clustering of TiB2 particles, formation of long rod-like Al3Ti particles, as well as high porosity level usually associate with the fabrication of in situ TiB2p/Al-alloy composites via conventional stir casting technique using Ti and B as reactants. High-intensity ultrasonic vibration was introduced in our research to solve the above issues. The process involved that the original in situ TiB2p/Al-12Si-4Cu sample with large clusters of TiB2 particles, large long rod-like Al3Ti particles and high porosity was remelted at 850 °C, and then ultrasonic vibration was applied to the melt with an ultrasonic probe. The microstructural evolution of the samples treated by ultrasonic vibration with different time was examined by using SEM. After treated by ultrasonic vibration for 12 min, large clusters of TiB2 particles were broken up effectively and TiB2 particles were dispersed uniformly in the matrix, and long rod-like Al3Ti particles were turned into blocky ones with the size of 10 μm due to the effect of ultrasonic stirring. In the meantime, the porosity in the composites decreased from about 6.5% to 0.86% due to the effect of ultrasonic degassing. Microhardness test suggested that a homogeneous microstructure of the composite was achieved after ultrasonic treatment. An effective approach using high-intensity ultrasonic vibration to optimize the microstructures of the particulate reinforced Al-alloy composites was proposed, and the mechanism of the effect of high-intensity ultrasonic vibration on the microstructural evolution of the reinforcements and degassing of composites was also discussed in our research. 相似文献
12.
T.S.R.Ch. Murthy J.K. Sonber C. Subramanian R.K. Fotedar Sunil Kumar M.R. Gonal A.K. Suri 《International Journal of Refractory Metals and Hard Materials》2010
A new composite of TiB2 with CrSi2 has been prepared with excellent oxidation resistance. Dense composite pellets were fabricated by hot pressing of powder mixtures. Microstructural characterization was carried out by XRD and SEM with EDAX. Mechanical and physical properties were evaluated. Extensive oxidation studies were also carried out. A near theoretical density (99.9% TD) was obtained with a small addition of 2.5 wt.% CrSi2 by hot pressing at 1700 °C under a pressure of 28 MPa for 1 h. The microstructure of the composite revealed three distinct phases, (a) dark grey matrix of TiB2, (b) black phase – rich in Si and (c) white phase – Cr laden TiB2. Hardness and fracture toughness were measured as 29 ± 2 GPa and 5.97 ± 0.61 MPa m1/2, respectively. Crack branching, deflection and bridging mechanisms were responsible for the higher fracture toughness. With increase in CrSi2 content, density, hardness and fracture toughness values of the composite decreased. Thermo gravimetric studies revealed the start of oxidation of the composite at 600 °C in O2 atmosphere. Isothermal oxidation of these composites showed better oxidation resistance by formation of a protective oxide layer. TiO2, Cr2O3 and SiO2 phases were identified on the oxidized surface. Effects of CrSi2 content, temperature and duration of oxidation on the oxide layer formation are reported. Activation energy of the composite was calculated as ∼110 kJ/mol using Arrhenius equation. Diffusion controlled mechanism of oxidation was observed in all the composites. 相似文献
13.
S. Guruvenket J.E. Klemberg-Sapieha L. Martinu 《Surface & coatings technology》2009,203(19):2905-2911
The use of hard and superhard nanocomposite (nc) coatings with tailored functional properties is limited when applied to low alloy steel substrates due to their low load carrying capacity. Specifically in this work, in order to enhance the performance of martensitic SS410 substrates, we applied a duplex process which consisted of surface nitriding by radio-frequency plasma followed by the deposition of single layer (TiN, nc-TiN/a-SiNx or nc-TiCN/a-SiCN) or multilayer (TiN/nc-TiN/a-SiNx, TiN/nc-TiCN/a-SiCN) coating systems prepared by plasma enhanced chemical vapor deposition (PECVD). We show that plasma nitriding gives rise to a diffusion layer at the surface due to diffusion of nitrogen and formation of the α-Fe and ε-Fe2N phases, respectively, leading to a surface hardness, H, of 11.7 GPa, compared to H = 5 GPa for the untreated steel. Among the TiN, nc-TiN/a-SiNx and nc-TiCN/a-SiCN coatings, the latter one possesses the highest H value of 42 GPa and the highest H3/Er2 ratio of 0.83 GPa. Particularly, the TiN/nc-TiCN/a-SiCN multilayer coating system exhibits superior tribological properties compared to single layer TiN and multilayer TiN/nc-TiN/a-SiNx coatings: this includes excellent adhesion, low friction (Cf = 0.17) and low wear rate (K = 1.6 × 10− 7 mm3/N m). The latter one represents an improvement by a factor of 600 compared to the bare SS410 substrate. The significance of the relationship between the H/E and H3/Er2 ratios and the tribological performance of the nano-composite coatings is discussed. 相似文献
14.
G.B. Raju Bikramjit Basu A.K. Suri 《International Journal of Refractory Metals and Hard Materials》2010
The present communication reports the effect of MoSi2 addition on high temperature thermal conductivity and room temperature (RT) electrical properties of TiB2. The thermal diffusivity and the thermal conductivity of the hot pressed TiB2–MoSi2 samples were measured over a range from room temperature to 1000 °C using the laser-flash technique, while electrical resistivity was measured at RT using a four linear probe method. The reciprocal of thermal diffusivity of TiB2 samples exhibit linear dependence on temperature and the measured thermal conductivity of TiB2-2.5% MoSi2 composites correlate well with the theoretical predictions from Hashin’s model and Hasselman and Johnson’s model. A common observation is that the thermal conductivity of all the samples slightly increases with temperature (up to 200 °C) and then decreases with further increasing temperature. It is interesting to note that both the thermal conductivity and electrical conductivity of TiB2 samples enhanced with the addition of 2.5 wt.% MoSi2 sinter additive. Among all the samples, TiB2-2.5 wt.% MoSi2 ceramics measured with high thermal conductivity (77 W/mK) and low electrical resistivity (12 μΩ-cm) at room temperature. Such an improvement in properties can be attributed to its high density and low volume fraction of porosity. On the other hand, both the thermal and electrical properties of TiB2 were adversely affected with further increasing the amount of MoSi2 (10 wt.%). 相似文献
15.
《Intermetallics》2007,15(2):206-210
Extremely fine and homogeneous TiN/TiB2/Ti-silicide composite powders have been synthesized from mixtures of Ti, BN and Si3N4 powders by high-energy ball milling through a mechanically activated self-sustaining reaction. They have a microstructure consisting of TiN and TiB2 crystallites of less than 15 nm embedded in amorphous TiSi2 or Ti5Si3 matrix. When these nanocomposite powders were annealed at high temperatures, the microstructure did not change significantly and TiN and TiB2 mutually suppressed the grain growth of both phases effectively. 相似文献
16.
Titanium diboride (TiB2) and its ceramic composites were prepared by hot pressing process. The sintering process, phase evolution, microstructure and mechanical properties of TiB2 ceramics prepared by using different milling media materials: tungsten carbide (WC/Co) or SiAlON was studied. It was found that the inclusion of WC/Co significantly improved the sinterability of the TiB2 ceramics. A core/rim structure with pure TiB2 as the core and W-rich TiB2, i.e. (Ti,W)B2 as the rim was identified. Microstructure analysis revealed that this core/rim structure was formed through a dissolution and re-precipitation process. In addition, silicon carbide (SiC) was also introduced to form TiB2–SiC composites. The addition of SiC as the secondary phase not only improved the sinterability but also led to greatly enhanced fracture toughness. The optimum mechanical properties with Vickers hardness ~ 22 GPa, and fracture toughness ~ 6 MPa m1/2 were obtained on TiB2–SiC composites milled with WC/Co. 相似文献
17.
TiB2–SiC ceramic composites, with different contents of SiC whiskers (SiCw), as a ceramic sinter-additive, were prepared by the hot pressing process at 1850 °C for 2 h under a pressure of 20 MPa. For comparison, a monolithic TiB2 ceramic was also fabricated under the identical temperature, pressure, atmosphere, and holding time by the hot pressing process. The effects of fabrication process and SiC whiskers on microstructural features, phase evolution and mechanical properties were investigated. Hardness measurements revealed an initial increase in hardness for TiB2–SiC compared to TiB2. Also the improvement of the fracture toughness was attributed to the toughening and strengthening effects of SiC whiskers such as crack deflection. The results showed that promoted densification of TiB2–SiC ceramic composites is due to addition of SiC whiskers and reduction of oxide impurities by reacting with SiC whiskers and removing them from the surface layer of TiB2 particles. The reaction between TiB2 particles and SiC whiskers led to in-situ formation of TiC phase in the matrix as well. In general, it is concluded that the sinterability of TiB2-based composites was remarkably improved by introducing SiC whiskers compared to the single phase TiB2 ceramic. 相似文献
18.
J.K. SonberR.K. Fotedar A.K. Suri 《International Journal of Refractory Metals and Hard Materials》2011,29(1):21-30
This paper presents the results of experimental investigations carried out on the synthesis of pure ZrB2 by boron carbide reduction of ZrO2 and densification with the addition of HfB2 and TiSi2. Process parameters and charge composition were optimized to obtain pure ZrB2 powder. Monolithic ZrB2 was hot pressed to full density and characterized. Effects of HfB2 and TiSi2 addition on densification and properties of ZrB2 composites were studied. Four compositions namely monolithic ZrB2, ZrB2 + 10% TiSi2, ZrB2 + 10% TiSi2 + 10% HfB2 and ZrB2 + 10% TiSi2 + 20% HfB2 were prepared by hot pressing. Near theoretical density (99.8%) was obtained in the case of monolithic ZrB2 by hot pressing at 1850 °C and 35 MPa. Addition of 10 wt.% TiSi2 resulted in an equally high density of 98.9% at a lower temperature (1650 °C) and pressure (20 MPa). Similar densities were obtained for ZrB2 + HfB2 mixtures also with TiSi2 under similar conditions. The hardness of monolithic ZrB2 was measured as 23.95 GPa which decreased to 19.45 GPa on addition of 10% TiSi2. With the addition of 10% HfB2 to this composition, the hardness increased to 23.08 GPa, close to that of monolithic ZrB2. Increase of HfB2 content to 20% did not change the hardness value. Fracture toughness of monolithic sample was measured as 3.31 MPa m1/2, which increased to 6.36 MPa m1/2 on addition of 10% TiSi2. With 10% HfB2 addition the value of KIC was measured as 6.44 MPa m1/2, which further improved to 6.59 MPa m1/2 with higher addition of HfB2 (20%). Fracture surface of the dense bodies was examined by scanning electron microscope. Intergranular fracture was found to be a predominant mode in all the samples. Crack propagation in composites has shown considerable deflection indicating high fracture toughness. An oxidation study of ZrB2 composites was carried out at 900 °C in air for 64 h. Specific weight gain vs time plot was obtained and the oxidized surface was examined by XRD and SEM. ZrB2 composites have shown a much better resistance to oxidation as compared to monolithic ZrB2. A protective glassy layer was seen on the oxidized surfaces of the composites. 相似文献
19.
Yongsheng Liu Litong Zhang Laifei Cheng Wenbin Yang Weihua Zhang Yongdong Xu 《Corrosion Science》2009,51(4):820-826
An amorphous boron carbide (a-BC) coating was prepared by LPCVD process from BCl3-CH4-H2-Ar system. XPS result showed that the boron concentration was 15.0 at.%, and carbon was 82.0 at.%. One third of boron was distributed to a bonding with carbon and 37.0 at.% was dissolved in graphite lattice. A multiple-layered structure of CVD SiC/a-BC/SiC was coated on 3D C/SiC composites. Oxidation tests were conducted at 700, 1000, and 1200 °C in 14 vol.% H2O/8 vol.% O2/78 vol.% Ar atmosphere up to 100 h. The 3D C/SiC composites with the modified coating system had a good oxidation resistance. This resulted in the high strength retained ratio of the composites even after the oxidation. 相似文献
20.
The formation, microstructure and properties of high-density TiN/Ti5Si3 ceramic composites created by the pyrolysis of preceramic polymer with filler were investigated. Methylpolysiloxane was mixed
with TiH2 as filler and ceramic composites prepared by pyrolysis at 1200°C to 1600°C under N2, Ar and vacuum were studied. When a specimen with 70 vol.% TiH2 was pyrolyzed up to 1600°C in a vacuum after a preheat treatment at 850°C in a N2 atmosphere and subsequently heat-treated at 1600°C for 1 h under Ar at a pressure of 2 MPa, a ceramic composite with full
density was obtained. The microstructure of the ceramic composite was composed of TiN and Ti5Si3 phases. Under specific pyrolysis conditions, a ceramic composite with a density of 99.2 TD%, a Vickers hardness of 18 GPa,
a fracture toughness of 3.5 MPam1/2, a flexural strength of 270 MPa and a electrical conductivity of 6200 ohm−1·cm−1 was obtained. 相似文献