Method of making a high temperature body of uniform porosity

Claim 1

The method of forming a porous body resistant to high temperatures typically exceeding 6,000*F which comprises compacting more than one selected size fractions of generally spherical particles of tungsten, assembled one size fraction at a time, to produce a porous mass, each of said size fractions being mechanically treated so that the distribution of particles is relatively uniform and mixtures of different size fractions being mechanically treated so that the smaller size fractions nest throughout in the voids of the larger fractions whereby a porous mass of substantially uniform porosity is produced, and thereafter reacting within the pores of said mass at a temperature which does not significantly alter the mechanical properties of said mass, one or more of the class of compounds consisting of tungsten hexafluoride and tungsten hexachloride with hydrogen to deposit tungsten from said compounds in the pores of said mass to cement said mass into a rigid high-temperature resisting body, the said reacting taking place at a rate and temperature as to assure uniformity of penetration and deposit and fine-grain structure of the deposited tungsten.

Claim 2

The method of forming a body of substantially uniform communicating porosity throughout and of predetermined density comprising compacting into a mass of a density smaller than said predetermined density, more than one selected size fractions of a powder of one or more materials of the class of materials consisting of tungsten, niobium, tantalum, zirconium, titanium, vanadium, silicon, rhenium, hafnium, chromium, and molybdenum, the particles of said powder having substantially spherical form, the particles being assembled one size fraction at a time and each of said size fractions being mechanically treated so that the distribution of particles is relatively uniform and mixtures of different size fractions being mechanically treated so that the smaller particles nest throughout in the voids of the larger fractions, whereby a porous mass of substantially uniform porosity is produced, said size fractions being selected so that said mass has said smaller density; and reacting within the pores of said mass one or more of the halides of said one or more materials with hydrogen or the like to deposit, without significant alteration in the geometry and uniformity of the pores, said one or more materials in said mass to cement said mass into a rigid body, the amount of said material deposited being such that said body has said predetermined density.

Claim 4

A method for the manufacture of an element of construction resisting thermal shocks and mechanical stresses, e.g. a rocket nozzle or nose by depositing of a binding metal from the gas phase in the interior of a preformed skeleton-like body, characterized in this that a green body is produced by compacting of generally spherical particles of more than one size fractions of a high temperature resisting and mechanically resisting material, e.g. tungsten, to a porous body of corresonding dimensions in such a way that a contiguous, homogeneous pores-space of substantially uniform porosity throughout is formed, the said size fractions being assembled one size fraction at a time, so that the particles of smaller size fractions are effectively nested throughout in the volumes defined between the particles of larger size fractions, and further characterized in this that a gaseous compound of the binding metal, e.g., tungsten halide, with a reducing agent, e.g., hydrogen, is brought to reaction within the pores of the formed body in such manner that, without significant alteration of the geometry and uniformity of the pores, the binding metal is deposited in the pores and will cement the particles together.