Injection of a ceramic into a mould

Claim 1

A METHOD OF PRODUCING AN ARTICLE FROM A MIXTURE OF ALPHA SILICON CARBIDE, GRAPHITE AND A BINDER THEREOF, INCLUDNG THE STEPS OF CHARGING A CHAMBER WITH THE MIX ATTACHING THE CHAMBER TO A MOULD MEMBER, HEATING THE ASSEMBLY, FORCING THE MIX THRUGH A NOZZLE IN THE CHAMBER SO AS TO FIRSTLY COMPACT THE MIX AND SECONDLY INJECT IT INTO SAID MOULD MEMBER, INCREASING SAID FORCE SO AS TO FURTHER COMPACT THE MIX WHILST IN THE MOULD MEMBER, THEN REMOVING SAID FORCE, SEPARATING THE CHAMBER FROM THE MOULD MEMBER AND THEN THE MIX FROM THE MOULD MEMBER.

Claim 2

A METHOD OF PRODUCING AN ARTICLE FROM A MIXTURE OF ALPHA SILICON CARBIDE, GRAPHITE AND A BINDER THEREOF, INCLUDNG THE STEPS OF CHARGING A CHAMBER WITH THE MIX ATTACHING THE CHAMBER TO A MOULD MEMBER, HEATING THE ASSEMBLY, FORCING THE MIX THRUGH A NOZZLE IN THE CHAMBER SO AS TO FIRSTLY COMPACT THE MIX AND SECONDLY INJECT IT INTO SAID MOULD MEMBER, INCREASING SAID FORCE SO AS TO FURTHER COMPACT THE MIX WHILST IN THE MOULD MEMBER, THEN REMOVING SAID FORCE, SEPARATING THE CHAMBER FROM THE MOULD MEMBER AND THEN THE MIX FROM THE MOULD MEMBER.

Claim 6

A method of producing an injection molded article composed of silicon carbide, comprising the steps of: a. mixing together alpha silicon carbide, graphite and a binder therefor to form a mix; b. charging the thus prepared mix under pressure into a chamber to densify the mix, the chamber fitted to a mold part which together constitute a molding assembly; c. heating the entire assembly thereby improving the flow characteristics of the mix contained within the chamber; d. increasing the pressure on the mix within the chamber and forcing the mix through a nozzle in the chamber to (i) further compact the mix, and (ii) inject the mix into the mold part; e. further increasing the pressure on the mix in the mold part to further compact the mix therein; f. discontinuing the applied pressure; g. separating the chamber from the mold piece; h. separating the mold piece while still heated and removing the injector molded mix; i. heating the injection molded mix to remove the binder; j. heating the injection molded mix of step (i) in a vacuum or an inert atmosphere in the presence of molten silicon which reacts exothermically with the graphite to form beta silicon grains; and k. reaction sintering together the alpha silicon carbide and beta silicon carbide to produce an injection molded ceramic article composed of beta silicon carbide, alpha silicon carbide and silicon.

Claim 7

A method of producing an injection molded article composed of silicon carbide, comprising the steps of: a. mixing together alpha silicon carbide, graphite and a binder therefor to form a mix; b. charging the thus prepared mix under pressure into a chamber to densify the mix, the chamber fitted to a mold part which together constitute a molding assembly; c. heating the entire assembly thereby improving the flow characteristics of the mix contained within the chamber; d. increasing the pressure on the mix within the chamber and forcing the mix through a nozzle in the chamber to (i) further compact the mix, and (ii) inject the mix into the mold part; e. further increasing the pressure on the mix in the mold part to further compact the mix therein; f. discontinuing the applied pressure; g. separating the chamber from the mold piece; h. separating the mold piece while still heated and removing the injector molded mix; i. heating the injection molded mix to remove the binder; j. heating the injection molded mix of step (i) in a vacuum or an inert atmosphere in the presence of molten silicon which reacts exothermically with the graphite to form beta silicon grains; and k. reaction sintering together the alpha silicon carbide and beta silicon carbide to produce an injection molded ceramic article composed of beta silicon carbide, alpha silicon carbide and silicon.