Kinetic Features of Crystallization of Cubic Boron Nitride Single Crystals in the BNLiH(N,Se) System

Abstract

We have investigated the effect of selenium additions on the kinetics of the degree and rate of hexagonal to cubic BN conversion (hBN 4 cBN) as well as on the linear rate of the cBN crystal growth in the BN-LiH(N, Se) system. Experiments were performed in the temperature range 1940 to 2080 K at a pressure of 4.3 GPa. For 0.5, 1.0, and 3.0 mass% selenium addition, the activation energy of the process of cBN formation is found to be 45.0, 39.0, and 34.0 kJ/mol, respectively. The resulting crystals showed n-type conduction with a resistivity of lo5 to lo8 Q cm and a dislocation density of lo5 to lo3 cm-2.

Synthesis of Cubic Boron Nitride at Low-Temperature and Low-Pressure Conditions

“…Introduction. Cubic boron nitride has been investigated extensively by many researchers because it is an important material that is widely used in cutting tools, grinding, and abrasive materials because of its supreme hardness, high thermal conductivity, and high-temperature stability. − Usually, cubic BN (cBN) is obtained from the conversion of hBN to cBN at high temperature (1200−2000 °C) and high pressure (2.5−7.5 GPa) in the presence of catalyst or solvent . In addition, other methods have also been developed to prepare BN.…”

Novel boron‐rich aluminum nitride advanced ceramic materials

“…Depending on the pressure and temperature conditions, a transformation to the wurtzite [78][79][80] or cubic sphalerite 81,82 structure type may appear. The cubic variety of boron nitride has high hardness, high melting point, high thermal conductivity, large bulk moduli, and it is used in cutting tools and grinding, as abrasive material, [83][84][85] in protective coatings 86 and electronic devices. 87 In the previous studies, aluminum nitride was doped with different elements, for example, boron and gallium have been investigated theoretically.…”

Peculiarities of spontaneous crystallization of cubic boron nitride single crystal powders in the Li-B-N (H, Be) system

“…YO) was introduced into graphite-like boron nitride (hBN) as the catalyst-solvent, which was carefully mixed with easily decomposable additions containing hydrogen-and nitrogen (8.0wt.Yo) and 0.25 and 0.50 wt.% beryllium, respectively. As evidenced by our early investigations [3,4] concerning the influence of doping additions of Se and S (up to 7.0 wt.%) on the crystallization processes in the BN-Li3N system, the amount of beryllium in the mixture should not be too high since it suppresses the nucleation and growth of cBN single crystals. In this case, the degree of conversion does not exceed 0.05 and therefore the concentration of the doping addition in the experiments was not higher than 0.50wt.%.…”