Silicon nitride products and method for their production

A method comprising the steps of:

• providing a reactor having a chamber defined therein which has a longitudinal axis and longitudinally separated upstream and downstream ends, wherein the chamber comprises a combustion zone and a reaction zone such that the combustion zone longitudinally extends from said upstream end to a boundary between the zones and such that the reaction zone longitudinally extends from said boundary to said downstream end;
• providing a first nozzle which comprises a first tubular member having an outlet end which extends into the chamber;
• establishing a flow of a combustible mixture in the combustion zone so as to flow in a direction generally toward the reaction zone, wherein the combustible mixture comprises a mixture of a fuel and an oxidant;
• combusting the combustible mixture in the combustion zone to produce hot combustion products;
• injecting at least one reactant through the first tubular member and out the outlet end thereof into said chamber at said boundary such that the hot combustion products carry said at least one reactant in the reaction zone generally toward said downstream end, wherein temperature conditions in at least a portion of the reaction zone are at least about 1300.degree. C. and wherein the elemental molar ratio of carbon to oxygen for the combination of the combustible mixture and said at least one reactant is at least about 0.7:1, said at least one reactant being capable of reacting in the reaction zone to form a nitride compound;
• flowing a generally annular stream of a gas around the first tubular member in the direction of the outlet end of the first tubular member so as to flow into the chamber and so as to generally surround said at least one reactant in its flow from the outlet end;
• whereby a product comprising the nitride compound is produced in the reaction zone and deposits on the first nozzle are substantially prevented.

A method comprising the steps of:

• providing a reactor having a chamber defined therein which has a longitudinal axis and longitudinally separated upstream and downstream ends, wherein the chamber comprises a combustion zone and a reaction zone such that the combustion zone longitudinally extends from said upstream end to a boundary between the zones and such that the reaction zone longitudinally extends from said boundary to said downstream end;
• establishing a flow of a combustible mixture in the combustion zone so as to flow in a direction generally toward the reaction zone, wherein the combustible mixture comprises a mixture of a fuel and an oxidant comprising oxygen;
• combusting the combustible mixture in the combustion zone to produce hot combustion products;
• injecting at least one reactant into the chamber at said boundary such that said at least one reactant is substantially gaseous as injected into the chamber and such that the hot combustion products carry said at least one reactant in the reaction zone generally toward said downstream end, wherein temperature conditions in at least a portion of the reaction zone are at least about 1300.degree. C. and wherein the elemental molar ratio of carbon to oxygen for the combination of the combustible mixture and said at least one reactant is at least about 0.7:1, said at least one reactant being capable of reacting in the reaction zone to form a nitride compound;
• whereby a product powder comprising the nitride compound is produced in the reaction zone.

A method comprising the steps of:

• providing a reactor having a chamber defined therein which has a longitudinal axis and longitudinally separated upstream and downstream ends, wherein the chamber comprises a combustion zone and a reaction zone such that the combustion zone longitudinally extends from said upstream end to a boundary between the zones and such that the reaction zone longitudinally extends from said boundary to said downstream end;
• establishing a flow of a combustible mixture in the combustion zone so as to flow in a direction generally toward the reaction zone, wherein the combustible mixture comprises a mixture of a fuel and an oxidant;
• combusting the combustible mixture in the combustion zone to produce hot combustion products;
• injecting at least one reactant into the chamber at said boundary such that the hot combustion products carry said at least one reactant in the reaction zone generally toward said downstream end, wherein temperature conditions in at least a portion of the reaction zone are at least about 1300.degree. C. and wherein the hot combustion products provide at least about 15% of the energy needed to maintain said temperature conditions and further wherein the elemental molar ratio of carbon to oxygen for the combination of the combustible mixture and said at least one reactant is at least about 0.7:1, said at least one reactant being capable of reacting in the reaction zone to form a nitride compound;
• whereby a product powder comprising the nitride compound is produced in the reaction zone.

A method comprising the steps of:

• providing a reactor having a chamber defined therein which has a longitudinal axis and longitudinally separated upstream and downstream ends, wherein the chamber comprises a combustion zone and a reaction zone such that the combustion zone longitudinally extends from said upstream end to a boundary between the zones and such that the reaction zone longitudinally extends from said boundary to said downstream end;
• establishing a flow of a combustible mixture in the combustion zone so as to flow in a direction generally toward the reaction zone, wherein the combustible mixture comprises a mixture of a fuel and an oxidant;
• combusting the combustible mixture in the combustion zone to produce hot combustion products, wherein the fuel and oxidant are injected at a flow rate and the combustion zone is dimensioned such that there is substantially no free oxygen at the boundary;
• injecting at least one reactant into said chamber at said boundary such that the hot combustion products carry said at least one reactant in the reaction zone generally toward said downstream end, wherein temperature conditions in at least a portion of the reaction zone are at least about 1300.degree. C. and wherein the elemental molar ratio of carbon to oxygen for the combination of the combustible mixture and said at least one reactant is at least about 0.7:1, said at least one reactant being capable of reacting in the reaction zone to form a nitride compound;
• whereby a product powder comprising the nitride compound is produced in the reaction zone.

A method comprising the steps of:

• providing a reactor having a chamber defined therein which has a longitudinal axis and longitudinally separated upstream and downstream ends, wherein the chamber comprises a combustion zone and a reaction zone such that the combustion zone longitudinally extends from said upstream end to a boundary between the zones and such that the reaction zone longitudinally extends from said boundary to said downstream end;
• establishing a flow of a combustible mixture in the combustion zone as so to flow in a direction generally toward the reaction zone, wherein the combustible mixture comprises a mixture of a fuel and an oxidant, and wherein the fuel and oxidant are injected into the chamber at a location closely adjacent to the upstream end of the chamber in a direction generally parallel to the longitudinal axis;
• combusting the combustible mixture in the combustion zone to produce hot combustion products;
• injecting at least one reactant into said chamber at said boundary in a direction generally perpendicular to the longitudinal axis such that the hot combustion products carry said at least one reactant in the reaction zone generally toward said downstream end, wherein temperature conditions in at least a portion of the reaction zone are at least about 1300.degree. C. and wherein the elemental molar ratio of carbon to oxygen for the combination of the combustible mixture and said at least one reactant is at least about 0.7:1, said at least one reactant being capable of reacting in the reaction zone to form a nitride compound;
• whereby a product powder comprising the nitride compound is produced in the reaction zone.

A method comprising the steps of:

• providing a reactor having a chamber defined therein which has a longitudinal axis and longitudinally separated upstream and downstream ends, wherein the chamber comprises a combustion zone and a reaction zone such that the combustion zone longitudinally extends from said upstream end to a boundary between the zones and such that the reaction zone longitudinally extends from said boundary to said downstream end;
• establishing a flow of a combustible mixture in the combustion zone so as to flow in a direction generally toward the reaction zone, wherein the combustible mixture comprises a mixture of a fuel and an oxidant which is injected into the combustion zone and wherein the fuel and oxidant as injected is the only fuel and oxidant injected into the chamber;
• combusting the combustible mixture in the combustion zone to produce hot combustion products;
• injecting at least one reactant into the chamber at said boundary such that the hot combustion products carry said at least one reactant in the reaction zone generally toward said downstream end, wherein temperature conditions in at least a portion of the reaction zone are at least about 1300.degree. C. and wherein the elemental molar ratio of carbon to oxygen for the combination of the combustible mixture and said at least one reactant is at least about 0.7:1, said at least one reactant being capable of reacting in the reaction zone to form a nitride compound;
• whereby a product comprising the nitride compound is produced in the reaction zone.