Patent ID: 11858850
Assignee: LEATEC FINE CERAMICS CO., LTD.
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  H | IPC C  H

Claim 9:
10. A method for manufacturing a zirconia-alumina composite ceramic substrate, the manufacturing process including:
a ball milling step of using alumina with a powder particle size (D50) of 0.7-0.3 μm, zirconia with a powder particle size (D50) of 0.20-0.80 μm, and a pre-synthesized sintering additive with a powder size (D50) of 0.3 to 1.5 μm as starting powders for ball milling mixing and dispersion in an organic solvent at room temperature;
a slurry preparing step of preparing an alumina slurry mix with 1 to 15 wt. % of the zirconia, 0.01 to 5.0 wt. % of the sintering additive and the rest of the alumina;
a degassing step of degassing the slurry mix until a viscosity of the degassed slurry mix reaches a pre-set range of 8000 to 30000 cps;
a green tape forming step of casting the degassed slurry mix with the viscosity of 8000 to 30000 cps to form a zirconia-aluminum composite green tape roll with a thickness of 0.12 to 1.1 mm;
a punching step of punching the zirconia-aluminum composite green tape roll;
a calculation step of calculating size of a green sheet that is punched from the green tape roll based on a pre-tested sintering shrinkage rate to yield a punched green sheet with a size of 227×168 mm;
a sintering step of sintering said punched green sheet with a size of 227×168 mm through a furnace at a temperature of 1560 to 1660° C. and heating the punched green sheet with a size of 227×168 mm to form a zirconia-alumina composite substrate with a size of 190.5×138 mm and a thickness of 0.1 to 0.9 mm,
wherein the sintering additive is a pre-calcined synthetic sintering additive composed of calcium oxide, silicon dioxide and magnesium oxide in a ratio of calcium oxide 0.8 to 8.8 wt. %, silicon dioxide 56.7 to 61.7 wt. %, and magnesium oxide 32.5 to 37.5 wt. %,
wherein the sintering additive is produced by mixing the calcium oxide, silicon dioxide and magnesium oxide by a bead mill to obtain a silicon-magnesium-calcium mixture; drying the silicon-magnesium-calcium mixture, and after the silicon-magnesium-calcium mixture is dried, calcining the silicon-magnesium-calcium mixture to produce a silicon-magnesium-calcium compound.