Abstract: A silicon nitride based ceramic is formed of silicon nitride and at least two metal oxides of such a type that when the metal oxides are heated separately they form a spinel. Combination of said metal oxides and said silicon nitride as fine powders and sintering same at a specified temperature for a specified period of time results in a silicon nitride based ceramic having improved mechanical and chemical properties.
Abstract: Method and Apparatus for subjecting material to extreme compression, for instance in the making of artificial diamonds. The material is enclosed within a cluster of anvils. When pressure pads converge to bear upon the clustered anvils so that they slide against each other and the cluster contracts, the material within is compressed. The reaction of each anvil with its pressure pad is directed generally towards the material to be compressed but lies out-of-parallel with the interfaces of sliding movement of that anvil with its neighbours. The pad-anvil reaction can thus be resolved into components urging each anvil into contact with its neighbours, and thus supporting the anvil against fracture due to the high compression it undergoes along the pad-specimen axis.
May 30, 1974
Date of Patent:
March 30, 1976
National Research Development Corporation
Abstract: Method and manufacture are provided for preparing a reticulated foam structure by: investing an organic reticulated foam structure with an inorganic composition, which composition is inert under the conditions for forming the reticulated structure; allowing the inorganic suspension to set to form an investment; removing the organic reticulated foam structure; filling the voids of the investment with a fluid composition to form a reticulated casting; and dissolving the investment so as to leave a reticulated foam structure casting.