The present invention provides a composite pressure-sintered material comprising a continuous phase of hexagonal boron nitride and, dispersed therein, a second material comprising (a) at least one metal nitride selected from the group consisting of silicon, aluminium and titanium nitrides and (b) at least one stable metal oxide; wherein the amount of metal oxide is such that the second material does not contain more than 35% by weight of oxygen. It has been observed that this material possesses a low thermal expansion coefficient and therefore reveals good thermal shock resistance. Another characteristic of this material is its low wettability by molten steel which is thus responsible for excellent chemical resistance to liquid metal. Finally, this material is exceptionally mechanical wear resistant.