Bonded particulate ceramic materials and their manufacture

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.degree. C to about 600.degree. 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.degree. C at 760 mm/Hg, and being thermally decomposed at said temperature range from about 200.degree. C to about 600.degree. 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.dbd.O or P.dbd.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.