Slurry for forming mold, mold and method for producing mold
A slurry for forming a mold includes a silica sol as a dispersion medium and niobia-stabilized zirconia dispersed in the silica sol.
1. A slurry for forming a mold comprising:
a silica sol as a dispersion medium; and
a niobia-stabilized zirconia dispersed in the silica sol, wherein:
the niobia-stabilized zirconia is capable of being destabilized when about 1200° C. or more is reached and being separated into a niobia and a zirconia, and
a crystal structure of the separated zirconia varies below a temperature at which the destabilization occurs.
2. The slurry for forming a mold according to claim 1 ,
wherein the crystal structure of the separated zirconia has a tetragonal phase at a temperature of higher than 1000° C. and has an orthorhombic phase at a temperature of 1000° C. or less.
3. A mold comprising:
a primary layer and a backup layer provided from an inside in this order,
wherein at least one of the primary layer and the backup layer is formed by performing a heat treatment on the slurry for forming a mold according to claim 1 .
4. A method for producing a mold comprising:
a slurry production process of producing a slurry in which a niobia-stabilized zirconia is dispersed in a silica sol as a dispersion medium;
a slurry layer formation process of forming a slurry layer in which the slurry is adhered to a surface of a wax mold;
a stucco layer formation process of forming a stucco layer in which particles of a refractory material are adhered to a surface of the slurry layer; and
a heat treatment process of performing a heat treatment on the slurry layer and the stucco layer, wherein:
the niobia-stabilized zirconia is capable of being destabilized when about 1200° C. or more is reached and being separated into a niobia and a zirconia, and
a crystal structure of the separated zirconia varies below a temperature at which the destabilization occurs.
5. The method for producing a mold according to claim 4 ,
wherein the crystal structure of the separated zirconia has a tetragonal phase at a temperature of higher than 1000° C. and has an orthorhombic phase at a temperature of 1000° C. or less.
6. A mold comprising:
a primary layer and a backup layer provided from an inside in this order,
wherein the primary layer and the backup layer are formed by baking such that a niobia-stabilized zirconia layer formed from a slurry for forming a mold including a silica sol as a dispersion medium and a niobia-stabilized zirconia dispersed in the silica sol and a stucco layer formed from particles of a heat-resistant material are alternately laminated,
the niobia-stabilized zirconia is capable of being destabilized when about 1200° C. or more is reached and being separated into a niobia and a zirconia, and
a crystal structure of the separated zirconia varies below a temperature at which the destabilization occurs.
7. The mold according to claim 6 ,
wherein the crystal structure of the separated zirconia has a tetragonal phase at a temperature of higher than 1000° C. and has an orthorhombic phase at a temperature of 1000° C. or less.
8. A method for producing a mold comprising:
a slurry production process of producing a slurry in which a niobia-stabilized zirconia is dispersed in a silica sol as a dispersion medium;
a slurry layer formation process of forming a slurry layer in which the slurry is adhered to a surface of a wax mold;
a stucco layer formation process of forming a stucco layer in which particles of a refractory material are adhered to a surface of the slurry layer;
a drying process of drying the laminated slurry layer and the stucco layer; and
a heat treatment process of performing a heat treatment on the slurry layer and the stucco layer after repeating the slurry layer formation process, the stucco layer formation process, and the drying process a plurality of times, wherein:
the niobia-stabilized zirconia is capable of being destabilized when about 1200° C. or more is reached and being separated into a niobia and a zirconia, and
a crystal structure of the separated zirconia varies below a temperature at which the destabilization occurs.
9. The method for producing a mold according to claim 8 ,
wherein the crystal structure of the separated zirconia has a tetragonal phase at a temperature of higher than 1000° C. and has an orthorhombic phase at a temperature of 1000° C. or less.