Silicon nitride powder and silicon nitride-containing aqueous slurry
AssigneeUbe Industries, Ltd.
InventorsKoji Shibata, Hiroshi Yanagisawa, Tetsuo Yamada
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Abstract
Disclosed is a powder of silicon nitride particles having a specific surface area of from 5 to 20 m.sup.2 /g. When an aqueous solution of a polyvinyl alcohol having a mean degree of polymerization of X and a degree of saponification of Y (mol %) is adsorbed to the powder, the amount of saturated adsorption at 20.degree. C. is not higher than the amount of adsorption to be represented by: Amount of Adsorption (mg/m.sup.2)=0.000112X+0.523Y/100-0.207 (1) Also disclosed is a low-viscosity silicon nitride-containing aqueous slurry containing said powder.
Claims10
A powder of silicon nitride particles having a specific surface area of from 5 to 20 m.sup.2 /g, and an amount of saturated adsorption for polyvinyl alcohol at 20.degree. C. by a polyvinyl alcohol adsorption test, which is more than 0.10 mg/m.sup.2 and less than an amount of adsorption represented by following formula (1):
- amount of adsorption (mg/m.sup.2)=0.000112X+0.523Y/100-0.207(1)
- wherein X is a mean degree of polymerization of polyvinyl alcohol and Y is a degree of saponification (mol %) of polyvinyl alcohol.
A silicon nitride-containing aqueous slurry comprising,
- a powder of silicon nitride particles having a specific surface area of from 5 to 20 m.sup.2 /g, and an amount of saturated adsorption for polyvinyl alcohol at 20.degree. C. by a polyvinyl alcohol adsorption test, which is more than 0.10 mg/m.sup.2 and less than an amount of adsorption represented by following formula (1):
- amount of adsorption (mg/m.sup.2)=0.000112X+0.523Y/100-0.207(1)
- wherein X is a mean degree of polymerization of polyvinyl alcohol and Y is a degree of saponification (mol %) of polyvinyl alcohol, and
- a molding binder dispersed in water together with said powder.
A silicon nitride-containing aqueous slurry comprising,
- a powder of silicon nitride particles having a specific surface area of from 5 to 20 m.sup.2 /g, and
- polyvinyl alcohol dispersed in water together with said powder, wherein an amount of saturated adsorption of the powder for polyvinyl alcohol at 20.degree. C. is more than 0.10 mg/m.sup.2 and less than an amount of adsorption represented by following formula (1):
- amount of adsorption (mg/m.sup.2)=0.000112X+0.523Y/100-0.207(1)
- wherein X is a mean degree of polymerization of polyvinyl alcohol and Y is a degree of saponification (mol %) of polyvinyl alcohol.
A powder of silicon nitride particles prepared by pyrolyzing a reaction product of silicon halide and ammonia to form an amorphous silicon nitride powder and calcining the amorphous silicon nitride powder, said powder having a specific surface area of from 5 to 20 m.sup.2 /g, and an amount of saturated adsorption for polyvinyl alcohol at 20.degree. C. by a polyvinyl alcohol adsorption test, which is more than 0.10 mg/m.sup.2 and less than an amount of adsorption represented by following formula (1):
- amount of adsorption (mg/m.sup.2)=0.000112X+0.523Y/100-0.207(1)
- wherein X is a mean degree of polymerization of polyvinyl alcohol and Y is a degree of saponification (mol %) of polyvinyl alcohol.
Dependencies are inferred from the claim text.