Abstract: Silicon carbide sintered bodies having controlled porosity in the range of about 3-25 vol % are prepared from raw batches containing a multimodal distribution of silicon carbide particles and comprised of at least a first set of particles having one average grain size and a second set of particles having another average grain size larger than the first set of particles. The resulting pores are 3-5 microns in the largest dimension, with an aspect ratio between about 1/1 and about 3/1 . The porous bodies, e.g., in the form of mechanical seal members, exhibit good tribological properties.

Abstract: A neutron absorbing article, preferably in long, thin, flat form, suitable for but not necessarily limited to use in storage racks for spent nuclear fuel at locations between volumes of such stored fuel to absorb neutrons from said spent fuel and prevent uncontrolled nuclear reaction of the spent fuel material, is composed of finely divided boron carbide particles and a solid, irreversibly cured phenolic polymer forming a continuous matrix about the boron carbide particles, in such proportions that at least 6% of B.sup.10 from the boron carbide content is present therein.

Abstract: A neutron absorbing article, preferably in long, thin, flat form, suitable for but not necessarily limited to use in storage racks for spent nuclear fuel at locations between volumes of such stored fuel, to absorb neutrons from said spent fuel and prevent uncontrolled nuclear reaction of the spent fuel material, is composed of finely divided boron carbide particles and a solid, irreversibly cured phenolic polymer, forming a continuous matrix about the boron carbide particles, in such proportions that at least 6% of B.sup.10 from the boron carbide content is present therein.

Abstract: Neutron absorbing articles, such as those in plate form suitable for use in a storage rack for spent nuclear fuel and having such properties as to make them useful in such application for long periods of time, are made by an improved one-step curing method in which a mixture of boron carbide particles, powdered phenolic resin and a minor proportion of a liquid medium which boils at a temperature below 200.degree. C., preferably water, is compacted to desired article form and is cured at an elevated temperature, without simultaneous imposition of pressure in compacting or pressing means, so as to cause bonding of the irreversibly cured phenolic polymer resulting to the boron carbide particles and production of the neutron absorber in desired form.

Abstract: A neutron absorbing article, preferably in flat plate form and suitable for use in a storage rack for spent nuclear fuel, includes boron carbide particles, diluent particles and a solid, irreversibly cured phenolic polymer cured to a continuous matrix binding the boron carbide and diluent particles. The total content of boron carbide and diluent particles is a major proportion of the article and the content of cured phenolic polymer present is a minor proportion. By regulation of the ratio of boron carbide particles to diluent particles, normally within the range of 1:9 and 9:1 and preferably within the range of 1:5 to 5:1, the neutron absorbing activity of the product may be controlled, which facilitates the manufacture of articles of particular absorbing activities best suitable for specific applications.