EP0165707A2 — Method of sintering ceramics and metal-dispersed …

Claim 1

Independent Claim 77 words

A method of sintering ceramics, characterised in that the synthesis and sintering of ceramics are simultaneously carried out by utilizing the reaction heat generated when at least one metallic element selected from groups III, IVa, Va and VIa of the Periodic Table is combined with at least one nonmetallic element such as B, C, N and Si without the input of heat or preliminary heating of the ceramics at temepratures substantially lower that the usual sintering temperature.

Claim 2

Independent Claim 77 words

A method of sintering ceramics, characterised in that the synthesis and sintering of ceramics are simultaneously carried out by utilizing the reaction heat generated when at least one metallic element selected from groups III, IVa, Va and VIa of the Periodic Table is combined with at least one nonmetallic element such as B, C, N and Si without the input of heat or preliminary heating of the ceramics at temepratures substantially lower that the usual sintering temperature.

Claim 3

Dependent Claim 65 words

A method according to claim 1, characterised in that powders of the ceramics to be synthesized or powders of ceramics, which are different from the ceramics to be synthesized, are added to a mixture of said metallic elements and said nonmetallic elements as a diluent for the synthetic reaction, to carry out the sintering process while controlling the speed of the synthetic reaction of ceramics.

Claim 4

Dependent Claim 83 words

A method according to claim 1 or claim 2, characterised in that the mixture of said metallic elements and said nonmetallic elements is pressed and then a part of the pressed body is heated to start the synthetic reaction of ceramics thereby inducing the synthetic reaction of the parts adjacent to the part heated by the reaction heat generated by the synthetic reaction of ceramics to carry out the sintering process with turning the whole of the pressed body to ceramics in turn.

Claim 5

Dependent Claim 38 words

A method according to claim 3, characterised in that the synthetic reaction is started by heating with an electric carbon heater, by electron-beam heating, by high-frequency induction heating, by laser heating or by heating using combustion promoting agent.

Claim 6

Independent Claim 72 words

A method of sintering ceramics, characterised in that the densification of a sintered body is promoted by carrying out a synthesis under high pressures in the sintering process using the reaction heat generated when the ceramics are synthesized from the mixture of at least one metallic element selected from groups III, IVa, Va and VIa of the Periodic Table and at least one nonmetallic element such as B, C, N and Si.

Claim 7

Independent Claim 72 words

A method of sintering ceramics, characterised in that the densification of a sintered body is promoted by carrying out a synthesis under high pressures in the sintering process using the reaction heat generated when the ceramics are synthesized from the mixture of at least one metallic element selected from groups III, IVa, Va and VIa of the Periodic Table and at least one nonmetallic element such as B, C, N and Si.

Claim 8

Dependent Claim 51 words

A method according to claim 5, characterised in that the mixture of said metallic elements and said nonmetallic elements is pressed under high pressures until the porosity of the pressed body is 30% or less then the sintering is carried out utilizing the reaction heat generated during the synthesis of ceramics.

Claim 9

Independent Claim 85 words

A method of sintering metal-dispersed reinforced ceramics, characterised in that a powdery mixture comprising at least one metallic element selected from groups III, IVa, Va and VIa of the Periodic Table and at least one kind of nonmetallic element such as B, C, N and Si, in amounts such that metallic powders are present at a ratio larger than the stoichiometric ratio, is exothermically reacted under high pressure to synthesize ceramics and simultaneously the matrix of said ceramics is sintered while dispersing non-reacted metals therein..

Claim 10

Independent Claim 85 words

A method of sintering metal-dispersed reinforced ceramics, characterised in that a powdery mixture comprising at least one metallic element selected from groups III, IVa, Va and VIa of the Periodic Table and at least one kind of nonmetallic element such as B, C, N and Si, in amounts such that metallic powders are present at a ratio larger than the stoichiometric ratio, is exothermically reacted under high pressure to synthesize ceramics and simultaneously the matrix of said ceramics is sintered while dispersing non-reacted metals therein..

Claim 11

Independent Claim 145 words

A method of sintering metal-dispersed reinforced ceramics, characterised in that particles of the same kind of metal as that forming the ceramics are dispersed in the matrix of said ceramics, which are obtained by pressing a powdery mixture comprising at least one metallic element selected from groups III, IVa, and Va and VIa groups of the Periodic Table and at least one nonmetallic element such as B, C, N and Si so as to include the metallic powders at a ratio larger than the stoichiometric ratio and then heating a part of the pressed body to start the synthetic reaction and inducing the synthetic reaction of the parts adjacent to the heated part utilizing the reaction heat generated at that time, thereby making the whole of the pressed body react in turn to sinter, to bond said metallic particles strongly and chemically to said matrix.

Claim 12

Independent Claim 145 words

A method of sintering metal-dispersed reinforced ceramics, characterised in that particles of the same kind of metal as that forming the ceramics are dispersed in the matrix of said ceramics, which are obtained by pressing a powdery mixture comprising at least one metallic element selected from groups III, IVa, and Va and VIa groups of the Periodic Table and at least one nonmetallic element such as B, C, N and Si so as to include the metallic powders at a ratio larger than the stoichiometric ratio and then heating a part of the pressed body to start the synthetic reaction and inducing the synthetic reaction of the parts adjacent to the heated part utilizing the reaction heat generated at that time, thereby making the whole of the pressed body react in turn to sinter, to bond said metallic particles strongly and chemically to said matrix.

Claim 13

Independent Claim 134 words

A method of sintering metal-dispersed reinforced ceramics, characterised in that particles of the same kind of metal as that constructing the ceramics are dispersed in the matrix of said ceramics, which are obtained by making a powdery mixture comprising at least one metallic element selected from groups III, IVa, Va and VIa of the Periodic Table and at least one nonmetallic element such as B, C, N and Si so as to induce the metallic powders at a ratio larger than the stoichiometric ratio, reacting and then sintering by principally utilizing the reaction heat generated during the synthesis of the ceramics without adding external heat or starting the reaction at temperatures substantially lower than the usual sintering temperature of the ceramics to sinter, to bond said metallic particles strongly and chemically to said matrix.

Claim 14

Independent Claim 134 words

A method of sintering metal-dispersed reinforced ceramics, characterised in that particles of the same kind of metal as that constructing the ceramics are dispersed in the matrix of said ceramics, which are obtained by making a powdery mixture comprising at least one metallic element selected from groups III, IVa, Va and VIa of the Periodic Table and at least one nonmetallic element such as B, C, N and Si so as to induce the metallic powders at a ratio larger than the stoichiometric ratio, reacting and then sintering by principally utilizing the reaction heat generated during the synthesis of the ceramics without adding external heat or starting the reaction at temperatures substantially lower than the usual sintering temperature of the ceramics to sinter, to bond said metallic particles strongly and chemically to said matrix.

Claim 15

Independent Claim 106 words

A method of sintering ceramics, characterised in that a pressed body is prepared containing a powdery mixture, comprising at least one metallic element selected from groups III, IVa, Va and VIa groups of the Periodic Table and at least one nonmetallic element such as B, C, N and Si and locally heated from within to initiate an exothermic reaction between said metallic and nonmetallic powders and/or an exothermic reaction between said metallic powder and atmospheric gases and/or liquids, and wherein the reaction is made to progress continuously toward the surface of the pressed body in turn by utilizing the reaction heat, thereby obtaining the sintered body.

Claim 16

Independent Claim 106 words

A method of sintering ceramics, characterised in that a pressed body is prepared containing a powdery mixture, comprising at least one metallic element selected from groups III, IVa, Va and VIa groups of the Periodic Table and at least one nonmetallic element such as B, C, N and Si and locally heated from within to initiate an exothermic reaction between said metallic and nonmetallic powders and/or an exothermic reaction between said metallic powder and atmospheric gases and/or liquids, and wherein the reaction is made to progress continuously toward the surface of the pressed body in turn by utilizing the reaction heat, thereby obtaining the sintered body.

Claim 17

Dependent Claim 80 words

Metal-dispersed reinforced ceramic, characterised in that it is produced by dispersing powders of the same kind of metal as that constructing said ceramic in the matrix of said ceramic, which is synthesized by an exothermic reaction of a mixture comprising at least one metallic element selected from groups III, IVa, Va and VIa of the Periodic Table and at least one nonmetallic element such as B, C, N and Si, strongly and chemically bonding said metallic particles to said matrix.

Claim 18

Dependent Claim 80 words

Metal-dispersed reinforced ceramic, characterised in that it is produced by dispersing powders of the same kind of metal as that constructing said ceramic in the matrix of said ceramic, which is synthesized by an exothermic reaction of a mixture comprising at least one metallic element selected from groups III, IVa, Va and VIa of the Periodic Table and at least one nonmetallic element such as B, C, N and Si, strongly and chemically bonding said metallic particles to said matrix.

Claim 19

Dependent Claim 19 words

Metal-dispersed reinforced ceramics according to claim 11, characterised in that said dispersed metallic particles are approximately spherical in shape.

Claim 20

Dependent Claim 31 words

Metal-dispersed reinforced ceramics according to claim 11 or claim 12, characterised by that the phase of the dispersed metallic particles is included at a ratio of 70% or less by volume.

Method of sintering ceramics and metal-dispersed reinforced ceramics obtained thereby

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