scholarly journals Influence of binder systems on sintering characteristics, microstructures, and mechanical properties of PcBN composites fabricated by SPS

2022 ◽  
Vol 11 (2) ◽  
pp. 321-330
Author(s):  
Shuna Chen ◽  
Hengzhong Fan ◽  
Yunfeng Su ◽  
Wensheng Li ◽  
Jicheng Li ◽  
...  

AbstractCubic boron nitride (cBN) with high hardness, thermal conductivity, wear resistance, and chemical inertness has become the most promising abrasive and machining material. Due to the difficulty of fabricating pure cBN body, generally, some binders are incorporated among cBN particles to prepare polycrystalline cubic boron nitride (PcBN). Hence, the binders play a critical factor to the performances of PcBN composites. In this study, the PcBN composites with three binder systems containing ceramic and metal phases were fabricated by spark plasma sintering (SPS) from 1400 to 1700 °C. The sintering behaviors and mechanical properties of the composites were investigated. Results show that the effect of binder formulas on mechanical properties mainly related to the compactness, mechanical performances, and thermal expansion coefficient of binder phases, which affect the carrying capacity of the composites and the bonding strength between binder phases and cBN particles. The PcBN composite with SiAlON phase as binder presented optimal flexural strength (465±29 MPa) and fracture toughness (5.62±0.37 MPa·m1/2), attributing to the synergistic effect similar to transgranular and intergranular fractures. Meanwhile, the excellent mechanical properties can be maintained a comparable level when the temperature even rises to 800 °C. Due to the weak bonding strength and high porosity, the PcBN composites with Al2O3-ZrO2(3Y) and Al-Ti binder systems exhibited inferior mechanical properties. The possible mechanisms to explain these results were also analyzed.

2014 ◽  
Vol 665 ◽  
pp. 79-84
Author(s):  
Guo Duan Liu ◽  
Zi Li Kou ◽  
Xiao Zhi Yan ◽  
Li Lei ◽  
Duan Wei He

Cubic boron nitride (cBN) is a excellent super hard materials with superior mechanical properties that has been widely used in different industrial applications. Conventional cBN was sintered with binder in the cBN powder, and the binder affect the mechanical properties of cBN. Here we report that we sinter the polycrystalline cBN on WC-16wt%Co substrates without any sintering agent at the pressure 5.5 GPa and temperatures of 1300-1600°C for 10 min. In the sintering, we used 1-2μm fine grained cBN powder as the starting materials, also, liquid substance infiltrated from the substrates and occurred chemical reactions with cBN powder. Reaction contents were investigated at different temperatures according to X-ray diffraction (XRD). Plenty of direct BN-BN bonding was formed in the scanning electron microscopy ( SEM) observation.The hardness of best samples reach 38.5 GPa under the loading force of 5 kg, which have high hardness for the formation of direct BN-BN fine grains in the sample. .


2019 ◽  
Vol 126 (7) ◽  
pp. 075107 ◽  
Author(s):  
Vladimir L. Solozhenko ◽  
Volodymyr Bushlya ◽  
Jinming Zhou

2015 ◽  
Vol 655 ◽  
pp. 45-48
Author(s):  
Kun Li ◽  
Hai Yan Chen ◽  
Qiu Shuang He ◽  
Li Hua Dong

(0, 5, 10, 15, 20) vol% CBN-WC/Co composites were consolidated by ball milling and the following hot-pressing sintering method. WC, Co and CBN powders were used as the starting materials. The effects of the CBN content on the density, microstructure and mechanical properties of CBN-WC/Co composites were investigated. The results showed that the CBN content had remarkable influence on the microstructure and mechanical properties of CBN-WC/Co Composites. With the increasing content of CBN, the density decrease, while Vickers hardness and flexural strength increased initially to the maximum values and then decreased at CBN 10 vol%. When 10 vol% CBN-WC/Co powders were hot-pressing sintered at 1350°C and 20MPa for 90 min, an excellent Vickers hardness of 19.8GPa was achieved, combining a flexural strength of 682MPa.


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.


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