Spark Plasma Sintering of CBN-WC-10Co Composites

2007 ◽  
Vol 336-338 ◽  
pp. 1053-1055 ◽  
Author(s):  
Xiao Liang Shi ◽  
Gang Qin Shao ◽  
Xing Long Duan ◽  
R.Z. Yuan

Nanocomposite WC-10Co powder produced by spray pyrolysis-continuous reduction & carbonization technology and cubic boron nitride (CBN) plated with titanium by vacuum vapor deposit were used, and this paper adopted spark plasma sintering (SPS) process to prepare CBN enhanced ultrafine WC-10Co cemented carbide cermets composite material. The microstructure and mechanical properties of CBN-WC-10Co composites were investigated. The results show that CBN-WC-10Co composites consolidated by spark plasma sintering can reach 95.0 % relative density, and transverse rupture strength (TRS) is 1050 MPa, the average grain size of cermets matrix is less than 420 nm, and CBN-WC-10Co composites with excellent properties are achieved. The CBN still remains very good crystal shape after 1240°C spark plasma sintering, and there is not obvious clearance between CBN plated with titanium and the cermets matrix, the coated titanium layer can not only improve the thermal stability of CBN, but also increase the properties of CBN-WC-10Co composites.

2010 ◽  
Vol 37-38 ◽  
pp. 980-984 ◽  
Author(s):  
Xiao Qiang Li ◽  
Zhang Yi Xiao ◽  
Chao Yang ◽  
Sheng Guan Qu

Commerical pure WC powders of 0.2, 0.4, 0.8, 2.0 and 3.0 m in diameter were sintered by spark plasma sintering process at 1300 °C, respectively. By analyzing the XRD patterns of the initial powders and the microstructure of the sintered samples, it is affirmed that the powders with an average size of 0.8 m exhibits the best activity and sintering property. To optimize sintering temperature, the sintering of 0.8 m powders was carried out at 1200-1700 °C. The specimen sintered at 1300 °C has a density of 15.49 g/cm3 and an average grain size of about 0.7 m, and exhibits the most excellent mechanical properties. The corresponding Vickers hardness and transverse rupture strength are 2469 HV and 1656 MPa, respectively.


2008 ◽  
Vol 368-372 ◽  
pp. 601-603
Author(s):  
Xi Wei Qi ◽  
Ji Zhou ◽  
Zhen Xing Yue ◽  
Ming Ya Li ◽  
Xiu Mei Han

Dense NiCuZn ferrites consisting of fine grains were prepared by spark plasma sintering (SPS) at 750°C for 3 min under a uniaxial pressure of 15 MPa. The powders were densified to >95% of theoretical density by the SPS process, and the average grain size of the prepared NiCuZn ferrite was < 1 /m. The saturation magnetization of prepared specimens (without further annealing treatment) was approximate 50.54 emu/g, which was slightly smaller than that of 52.21 emu/g for specimens prepared by conventional sintering at 980°C for 4 h. Phase identifications indicated that prepared NiCuZn ferrite existed impurity phase (Cu2O), and Cu2O would gradually transform to CuO when annealing temperature increased.


2002 ◽  
Vol 17 (3) ◽  
pp. 575-581 ◽  
Author(s):  
Tomonari Takeuchi ◽  
Claudio Capiglia ◽  
Nalini Balakrishnan ◽  
Yasuo Takeda ◽  
Hiroyuki Kageyama

Dense BaTiO3 ceramics consisting of fine grains were prepared using fine powder (average grain size of 0.06 μm; BT006) as a starting material and the spark plasma sintering (SPS) method. The powder was densified to >95% of theoretical x-ray density by the SPS process, and the average grain size of the resulting ceramics was <0.5 μm; the particle size of the initial powder significantly affects the grain size of the resulting SPS pellets. Fixed-frequency (100 kHz), room-temperature permittivity measurements of the BT006-SPS ceramics showed relatively low values (3000–3500) compared with those (typically 5000) for SPS ceramics consisting of larger grains (approximately 1 μm). Lower permittivity was attributed to poor development of ferroelectric domains in the ceramics, which originated from incomplete development of the tetragonal structure as well as the presence of a local orthorhombic structure.


2008 ◽  
Vol 403 ◽  
pp. 241-242
Author(s):  
Mikinori Hotta ◽  
Takashi Goto

SiAlON-cubic boron nitride (cBN) composite was prepared by spark plasma sintering (SPS) using -SiAlON and cBN powders as starting materials, and the effect of holding time on densification, phase transformation and hardness of the composite was investigated. The SiAlON-cBN composite containing 20 vol% cBN sintered at 1650oC for 60s was densified to >97% of theoretical density. cBN phase transformed to hexagonal boron nitride (hBN) in the SiAlON-cBN composite with increasing holding time at 1650oC. Vickers hardness of the SiAlON-20vol%cBN composite sintered at 1650oC for 60-300s was 17.7GPa, and the hardness decreased with increasing holding time.


2004 ◽  
Vol 449-452 ◽  
pp. 1101-1104 ◽  
Author(s):  
Ji Soon Kim ◽  
S.-H. Jung ◽  
Young Do Kim ◽  
Chung Hyo Lee ◽  
Young Soon Kwon

Mechanically-alloyed NiAl powder was sintered by Spark-Plasma Sintering (SPS) process. Densification behavior and mechanical property were determined. Above 97% relative density was obtained after sintering at 1150oC for 5min. Crystallite size determined by the Scherrer method was approximately 80 nm. TEM observation revealed a relative larger crystallite size. X-ray diffraction analysis showed that the sintered bodies were composed mainly of NiAl phase together with Ni3Al phase. Sintered NiAl body showed an average Vicker’s hardness of 555Hv, transverse-rupture strength of 1393MPa, 4-point-bending strength of 1100MPa, and fracture toughness of 19.9MPa m-1/2


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