摘要:
Boron nitride containing titanium nitride in an amount of 0.05 to 10 wt.% which is produced at a relatively low temperature, utilizing a chemical vapor deposition technique. In the deposition process, boron, titanium and nitrogen source gases are introduced into an evacuated reactor together with a carrier and/or diluent gas and contacted with a heated substrate previously mounted in the reactor, whereby boron nitride with titanium nitride is deposited onto the substrate. The deposit thus obtained has a high density, a significantly improved heat-shielding ability, a high degree of anisotropy with respect to thermal diffusivity and a high chemical stability. By using such anisotropic boron nitride with BN ceramics, very useful BN type composite ceramics can be produced.
摘要:
Highly pure, high-density rhombohedral polycrystalline boron nitride substantially comprising rhombohedral crystals and having a three-fold axis of symmetry (an axis parallel to axis c according to hexagonal representation) oriented to one direction, which can be obtained in an arbitrary mass or thin film form by a chemical vapor deposition process of introducing a boron source gas and a nitrogen source gas and, optionally, a diluting and carrier gas into a reactor provided with a heated base to deposit boron nitride on the base, while providing a nitrogen source gas- and/or a carrier gas-diffusing layer around the heated base. The resulting boron nitride is extremely useful as semiconductors, crucibles for melting, various high-temperature jigs, high-frequency insulators, microwave transmitting apertures, and boron source for semi-conductors and, in addition, optimal as a precursor of high-pressure phase cubic boron nitride.
摘要:
Highly pure, high-density rhombohedral polycrystalline boron nitride substantially comprising rhombohedral crystals and having a three-fold axis of symmetry (an axis parallel to axis c according to hexagonal representation) oriented to one direction, which can be obtained in an arbitrary mass or thin film form by a chemical vapour deposition process of introducing a boron source gas and a nitrogen source gas and, optionally, a diluting and carrier gas into a reactor provided with a heated base to deposit boron nitride on the base, while providing a nitrogen source gas- and/or a carrier gas-diffusing layer around the heated base. The resulting boron nitride is extremely useful as semiconductors, crucibles for melting, various high-temperature jigs, high-frequency insulators, microwave transmitting apertures, and boron source for semi-conductors and, in addition, optimal as a precursor of high-pressure phase cubic boron nitride.
摘要:
A ceramics composite article of high strength and superior toughness, wherein whiskers are dispersed in its matrix and said dispersed whiskers are oriented parallel to the outer surface of the ceramics article and also in two-dimensionally random directions over the whole thickness from the outer surface to the inner surface of the ceramics article. The invention extends to a method of making such an article.