X-ray diffraction analysis of aluminum nitride sintered with cubic boron nitride

X-ray diffraction spectra of AlN after HP-HT sintering of a mixture containing AlN and c-BN have been examined. A residual elastic strain in the AlN lattice was found in the samples after the pressure was removed. It is envidenced by the decrease in both the lattice constant ratio (c/a) and the unit cell volume. Such a state of the lattice is typical of AlN at 8 GPa. For analysis of experimental results, a calculation was made of the thermoelastic strain caused by the difference in elastic moduli and thermal expansion coefficients of c-BN and AlN. The residual change in the c/a ratio and the unit cell volume in the AlN lattice after the pressure is removed is shown to be due to two factors: thermoelastic deformations in the phases of the composite and physico-chemical interactions between the components of the charge. (C) 1997 Elsevier Science S.A.