Bonded particulate ceramic materials and their manufacture

Claim 1

A method for the manufacture of self-bonded bodies from particulate materials selected from the group consisting of oxides of magnesium, silicon, aluminum, zirconium, beryllium, thorium, cerium, titanium, chromium, iron; metal aluminates, titanates, ferrites, and silicates; and carbides of silicon, tungsten, titanium, boron and tantalum characterized in that a shaped mixture containing the particulate material, from 0 to 6% of its weight of water, and from 1 to 10% of its weight of a heat-decomposable additive is subjected to initial green-strength providing conditions in which the additive is substantially not reactive towards any of the other ingredients of the mixture, then heated to a temperature within the range from about 200° C to about 600° C, at which the additive is thermally decomposed and bonding of said particulate material is effected, to form low strength bonded bodies, and then further heated to a higher temperature at which the particles of the particulate material become self-bonding, said additive being characterized by not boiling below 350° C at 760 mm/Hg, and being thermally decomposed at said temperature range from about 200° C to about 600° C to produce a non-volatile inorganic residue amounting to at least 5% of the original weight of the additive, said additive being an organo-phosphorus compound having a non-polymeric inorganic moiety and corresponding to the formula M(A.sub.x or .sub.x+1 Q.sub.x') (A'R).sub.y (R').sub.z wherein, M is an element selected from the group consisting of metals and silicon; A and A' are each O, S or N; Q is P, P═O or P═S; R and R' are each H, or a hydrocarbon, substituted hydrocarbon, organo-metallyl or-metalloxy radical, and R' may also be halogen; x and z are each an integer from zero to 5; x' is an integer from 1 to 5, and y is an integer from zero to 8, provided that y and z may not both be zero, and A'R and/or R' can be bonded either to M or Q and there may be more than one type of A'R and/or R' groups in the molecule.

Claim 2

A method for the manufacture of self-bonded bodies from particulate materials selected from the group consisting of oxides of magnesium, silicon, aluminum, zirconium, beryllium, thorium, cerium, titanium, chromium, iron; metal aluminates, titanates, ferrites, and silicates; and carbides of silicon, tungsten, titanium, boron and tantalum characterized in that a shaped mixture containing the particulate material, from 0 to 6% of its weight of water, and from 1 to 10% of its weight of a heat-decomposable additive is subjected to initial green-strength providing conditions in which the additive is substantially not reactive towards any of the other ingredients of the mixture, then heated to a temperature within the range from about 200° C to about 600° C, at which the additive is thermally decomposed and bonding of said particulate material is effected, to form low strength bonded bodies, and then further heated to a higher temperature at which the particles of the particulate material become self-bonding, said additive being characterized by not boiling below 350° C at 760 mm/Hg, and being thermally decomposed at said temperature range from about 200° C to about 600° C to produce a non-volatile inorganic residue amounting to at least 5% of the original weight of the additive, said additive being an organo-phosphorus compound having a non-polymeric inorganic moiety and corresponding to the formula M(A.sub.x or .sub.x+1 Q.sub.x') (A'R).sub.y (R').sub.z wherein, M is an element selected from the group consisting of metals and silicon; A and A' are each O, S or N; Q is P, P═O or P═S; R and R' are each H, or a hydrocarbon, substituted hydrocarbon, organo-metallyl or-metalloxy radical, and R' may also be halogen; x and z are each an integer from zero to 5; x' is an integer from 1 to 5, and y is an integer from zero to 8, provided that y and z may not both be zero, and A'R and/or R' can be bonded either to M or Q and there may be more than one type of A'R and/or R' groups in the molecule.