Dependence of the structure of cubic boron nitride polycrystals on the particle size of the starting graphitelike phase

1979 ◽  
Vol 18 (9) ◽  
pp. 664-668
Author(s):  
A. V. Kurdyumov ◽  
G. S. Oleinik ◽  
N. F. Ostrovskaya ◽  
A. N. Pilyankevich ◽  
N. N. Tkachenko ◽  
...  
Keyword(s):  
Particle Size ◽  
Boron Nitride ◽  
Cubic Boron Nitride

Dynamic consolidation of cubic boron nitride and its admixtures

1988 ◽  
Vol 3 (5) ◽  
pp. 1010-1020 ◽  
Author(s):  
Hua Tan ◽  
Thomas J. Ahrens
Keyword(s):  
Particle Size ◽  
Boron Nitride ◽  
Cubic Boron Nitride ◽  
Sem Analysis ◽  
Model Calculations ◽  
Boron Nitride Powder ◽  
Dynamic Consolidation ◽  
Consolidation Model ◽  
Heating Model ◽  
Hardness Values

Cubic boron nitride (C–BN)' powders admixed with graphite-structured boron nitride powder (g-DN), silicon carbide whisker (SCW), or silicon nitride whisker (SNW) were shock compacted to pressures up to 22 GPa. Unlike previous work with diamond and graphite [D. K. Potter and T. J. Ahrens, J. Appl. Phys. 63, 910 (1987) it was found that the addition of g-BN inhibited dynamic consolidation. Good consolidation was achieved with a 4–8 μm particle size C–BN powder admixed with 15 wt.% SNW or 20 wt.% SCW whereas a 37–44 μm particle size C–BN mixture was only poorly consolidated. Scanning electron microscopy (SEM) analysis demonstrates that SCW and SNW in the mixtures were highly deformed and indicated melt textures. A skin heating model was used to describe the physics of consolidation. Model calculations are consistent with SEM analysis images that indicate plastic deformation of SCW and SNW. Micro-Vickers hardness values as high as 50 GPa were obtained for consolidated C–BN and SNW mixtures. This compares to 21 GPa for single-crystal Al2O3 and 120 GPa for diamond.

Tool Wear of Polycrystalline Cubic Boron Nitride Compact Tools in Cutting Hardened Steel

2012 ◽  
Vol 488-489 ◽  
pp. 724-728 ◽  
Author(s):  
Tadahiro Wada
Keyword(s):  
Particle Size ◽  
Boron Nitride ◽  
Tool Wear ◽  
Tool Life ◽  
Cubic Boron Nitride ◽  
Cutting Speed ◽  
Hardened Steel ◽  
Polycrystalline Cubic Boron Nitride ◽  
Cbn Tool ◽  
High Cutting Speed

Using polycrystalline cubic boron nitride compact (cBN) tools, which have different cBN contents and cBN particle sizes, the influences of both the cBN content and the cBN particle size on tool wear in turning of hardened steel at various cutting speeds was experimentally investigated. Three types of cBN tools (a cBN content of 45-55% and 75%, and a cBN particle size of 0.5 μm and 5 μm, respectively) were tested. Furthermore, three kinds of chamfered and honed cutting edges were also used. The main results obtained are as follows: (1) In the case of the cBN tools with the same cBN particle size of 5.0 μm, the tool life of the cBN tool with a cBN content of 75% was longer than that of the cBN tool with a cBN content of 45% at low cutting speed. However, at high cutting speed, the tool life of the cBN tool with a cBN content of 75% was shorter. (2) The tool life of the cBN tool with both a cBN content of 55% and a cBN particle size of 0.5 μm was the longest. (3) The tool wear of cBN tools decreased with a decrease in chamfer width.

scholarly journals Effects of TiAl Alloy as a Binder on Cubic Boron Nitride Composites

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6335
Author(s):  
Yuxi Liu ◽  
Wei Zhang ◽  
Yingbo Peng ◽  
Guojiang Fan ◽  
Bin Liu
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Boron Nitride ◽  
Tial Alloy ◽  
Cubic Boron Nitride ◽  
Sintering Process ◽  
Good Oxidation Resistance ◽  
Tial Intermetallics ◽  
High Pressure Sintering ◽  
Sintering Method

Owing to their extreme hardness, cubic boron nitride (cBN) composites are widely used in cutting applications. The performance of cBN composites is closely related to the characteristics of the binder. Therefore, novel binders must be developed to improve the performance of cBN composites. In the present work, TiAl intermetallics were used as binders to fabricate cBN composites by employing a high-temperature and high-pressure sintering method. The phase transformation, sintering reaction mechanism, thermal stability, and mechanical properties of the resultant cBN composites were investigated. It was found that during the sintering process, Ti atoms preferentially reacted with boron nitride particles, whereas Al atoms enriched and transformed into TiAl3 phases and formed cBN/AlN, AlB2/TiN, and TiB2/TiAl3-layered structures eventually. The composites maintained good oxidation resistance at 1200 °C. A decrease in the particle size of the TiAl binder improved the uniformity of particle size distribution and increased the flexural strength of the composites.

Structural relationships in the synthesis of cubic boron nitride thin films by ion-assisted deposition

1994 ◽  
Vol 52 ◽  
pp. 638-639
Author(s):  
D. L. Medlin ◽  
T. A. Friedmann ◽  
P. B. Mirkarimi ◽  
M. J. Mills ◽  
K. F. McCarty
Keyword(s):  
Boron Nitride ◽  
Ion Irradiation ◽  
Cubic Boron Nitride ◽  
Film Stress ◽  
Bonded Phases ◽  
Structural Relationships ◽  
Precursor Material ◽  
Pressure Synthesis ◽  
Microstructure Of The Material

The allotropes of boron nitride include two sp2-bonded phases with hexagonal and rhombohedral structures (hBN and rBN) and two sp3-bonded phases with cubic (zincblende) and hexagonal (wurtzitic) structures (cBN and wBN) (Fig. 1). Although cBN is synthesized in bulk form by conversion of hBN at high temperatures and pressures, low-pressure synthesis of cBN as a thin film is more difficult and succeeds only when the growing film is simultaneously irradiated with a high flux of ions. Only sp2-bonded material, which generally has a disordered, turbostratic microstructure (tBN), will form in the absence of ion-irradiation. The mechanistic role of the irradiation is not well understood, but recent work suggests that ion-induced compressive film stress may induce the transformation to cBN.Typically, BN films are deposited at temperatures less than 1000°C, a regime for which the structure of the sp2-bonded precursor material dictates the phase and microstructure of the material that forms from conventional (bulk) high pressure treatment.

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