Method of sintering articles of silicon nitride
AssigneeMax-Planck-Gesellschaft zur Foedering der Wissenschaften e.V.
InventorsNils Claussen, Jurgen Jahn, Gunter Petzow
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Abstract
A novel method of sintering Si.sub.3 N.sub.4 shaped bodies which method comprises grinding Si.sub.3 N.sub.4 with the use of a grinding material down to a surface area magnitude of 10.5 to 35 m.sup.2 /g and an average particle size from 0.2 to 0.005 .mu.m, shaping the powder obtained, and sintering the compact under inert gas or nitrogen at a temperature from 1700.degree. to 1900.degree. C.
Claims9
In a method of pressureless sintering of silicon nitride (Si.sub.3 N.sub.4) wherein a formed powder compact is heated under an inert atmosphere without hot pressing to form a sintered article, the improvement comprising:
- grinding silicon nitride in an attritor mill using grinding bodies 1 to 3 mm in size of a material selected from the group consisting of a zirconium oxide material or silicate of aluminum, zirconium, beryllium, yttrium, and a combination thereof, to form a powder having an average particle size of 0.2 to 0.5 micrometers and a surface area of 10.5 to 35 square meters per gram;
- forming the powder compact using the ground powder;
- and
- heating the powder compact to a temperature in the range of 1700.degree. C. to 1900.degree. C. to sinter the compact into the sintered article.
In a method of pressureless sintering of silicon nitride (Si.sub.3 N.sub.4) wherein a formed powder compact is heated under an inert atmosphere without hot pressing to form a sintered article, the improvement comprising:
- grinding silicon nitride in an attritor mill using grinding bodies of silicon nitride of 1 to 3 mm in size to form a powder having an average particle size of 0.2 to 0.05 micrometers and a surface area of 10.5 to 35 square meters per gram wherein there is added in an amount of up to 10 weight-percent of the total weight of the additive and the Si.sub.3 N.sub.4 employed as a grinding material, at least one of an oxide or silicate of aluminum, magnesium, beryllium and zirconium;
- forming the powder compact using the ground powder;
- and
- heating the powder compact to a temperature in the range of 1700.degree. C. to 1900.degree. C. to sinter the compact into the sintered article.
In a method of pressureless sintering of silicon nitride (Si.sub.3 N.sub.4) wherein a formed powder compact is heated under an inert atmosphere without hot pressing to form a sintered article, the improvement comprising:
- grinding silicon nitride in an attritor mill using grinding bodies of 1 to 3 mm in size of a material selected from the group consisting of an oxide or a silicate of aluminum, zirconium, beryllium, yttrium, and a combination thereof, to form a powder having an average particle size of 0.2 to 0.05 micrometers and a surface area of 10.5 to 35 square meters per gram;
- forming the powder compact using the ground powder;
- and
- heating the powder compact to a temperature in the range of 1700.degree. C. to 1900.degree. C. to sinter the compact into the sintered article, the sintered article having a lower limit value K.sub.IC of 4.3 MN/m.sup.3/2.
In a method of pressureless sintering of silicon nitride (Si.sub.3 N.sub.4) wherein a formed powder compact is heated under an inert atmosphere without hot pressing to form a sintered article, the improvement comprising:
- grinding silicon nitride in an attritor mill using grinding bodies of 1 to 3 mm in size and of a material of oxide or silicate of magnesium to form a powder having an average particle size of 0.2 to 0.05 micrometers and a surface area of 10.5 to 35 square meters per gram;
- forming the powder compact using the ground powder;
- and
- heating the powder compact to a temperature in the range of 1700.degree. C. to 1900.degree. C. to sinter the compact into the sintered article.
Dependencies are inferred from the claim text.