Possible role of oxygen impurities in degradation of Nc-TiN/a-Si3N4 nanocomposites

摘要: The recently reported strong effect of minor oxygen impurities on the degradation mechanical properties superhard nc-TiN∕a-Si3N4 can be, by analogy with similar effects known in metallic alloys, understood basis a simple size large O2− impurity species incorporated into Si3N4 interface. electronic sites within interface is also likely to play an important role weakening Si–N and, possibly lesser extent, Ti–N bonds. A model which assumes that strength (and hardness) these materials approximately proportional reciprocal surface coverage TiN nanocrystals shows surprisingly good agreement measured data.