Method for manufacturing ceramic heater
A method for manufacturing a ceramic heater includes mixing a conductive ceramic powder, an insulating ceramic powder, a sintering aid powder, and a solvent so as to obtain a slurry, drying the slurry so as to obtain a heating-element material powder, forming a green resistance-heating element from the heating-element material powder, embedding the green resistance-heating element in a ceramic substrate, and firing a resultant assembly. Water is used as the solvent. Drying of the slurry is performed by use of a fluidized-bed drying apparatus, a rotary drying apparatus, or a vibratory drying apparatus and, the apparatus being employed in combination with a medium for pulverization.
1. A method for manufacturing a ceramic heater comprising the steps of:
providing a conductive ceramic powder, an insulating ceramic powder, a powdered sintering aid and a water containing solvent;
mixing the conductive ceramic powder, the insulating ceramic powder, the sintering aid and solvent to thereby form a slurry;
drying the slurry to obtain a heating-element material powder;
forming a resistance-heating-element from the heating-element material powder;
providing a ceramic substrate;
embedding the resistance-heating element in the ceramic substrate to form a resultant assembly; and,
wherein the conductive ceramic powder and insulating powder each has a 50% particle size of about 1 μm; and,
firing the resultant assembly to thereby form a ceramic heater.
2. The method for manufacturing a ceramic heater according to claim 1 , in which the solvent is predominately water and in which the slurry is dried in a fluidized-bed drying apparatus.
3. The method for manufacturing a ceramic heater according to claim 1 , in which the solvent is predominately water and in which the slurry is dried in a rotary drying apparatus.
4. The method for manufacturing a ceramic heater according to claim 1 , in which the solvent is predominately water and in which the slurry is dried in a vibratory drying apparatus.
5. The method for manufacturing a ceramic heater according to claim 1 , in which the solvent is predominately water and which includes the use of a medium in the drying step.
6. The method for manufacturing a ceramic heater according to claim 1 , in which the insulating ceramic powder comprises Si 3 N 4 and the conductive ceramic powder comprises a material selected from the group consisting of TiN, MoSi WSi 2 and WC.
7. The method for manufacturing a ceramic heater according to claim 5 , in which the medium comprises a medium for pulverization.
8. The method for manufacturing a ceramic heater according to claim 5 in which the medium comprises a plurality of objects selected from the group consisting of ceramics, resins and resin coated objects.
9. The method for manufacturing a ceramic heater in accordance with claim 5 , in which the medium comprises a plurality of objects in the form of at least one of balls, cubes, tubes and plate like shapes.
10. A method for manufacturing a glow plug for a diesel engine, said method comprising the steps of:
providing a mass of a conductive ceramic powder, a mass of an insulating ceramic powder, a mass of a powdered sintering aid and a solvent which is predominately water;
forming a slurry by mixing the mass of conductive ceramic powder, the mass of an insulating ceramic powder, the mass of a powdered sintering aid and the solvent;
drying the slurry to obtain a heating element material powder by passing a hot gas though the slurry while maintaining the powder in a fluidized state;
forming a green resistance-heating element from the heating element material powder;
providing a ceramic substrate;
embedding the resistance-heating element in the ceramic substrate to form a resultant assembly;
wherein the conductive ceramic powder and insulating powder each has a 50% particle size of about 1 μm; and
firing the resultant assembly to thereby form a glow plug for a diesel engine.
11. A method for manufacturing a glow plug for a diesel engine according to claim 10 , in which the conductive ceramic powder, insulating ceramic powder and powdered sintering aid are individually purified and pulverized.
12. A method for manufacturing a glow plug for a diesel engine according to claim 11 , in which the drying of the slurry includes the use of a hot gas at a temperature of between about 100 C to about 200 C.
13. The method for manufacturing a glow plug for a diesel engine according to claim 10 , which includes the step of dispersing the slurry on the surfaces of a medium.
14. A method for manufacturing a glow plug for a diesel engine according to claim 13 , which includes the step of exfoliating dried powder from the surface of the medium.
15. A method for manufacturing a glow plug for a diesel engine according to claim 10 , in which the conductive ceramic powder and insulating powder and sintering aid powder are dispersed in an ion-exchange treated water.
16. A method for manufacturing a glow plug for a diesel engine, said method comprising the steps of:
providing a mass of a conductive ceramic powder, a mass of an insulating ceramic powder, a mass of a powdered sintering aid and a solvent which is predominately water;
forming a slurry by mixing the mass of conductive ceramic powder, the mass of an insulating ceramic powder, the mass of a powdered sintering aid and the solvent;
drying the slurry to obtain a heating element material powder by passing a hot gas through the slurry while maintaining the powder in a fluidized state;
forming a green resistance-heating element from the heating element material powder;
providing a ceramic substrate
embedding the resistance-heating element in the ceramic substrate to form a resultant assembly;
wherein the sintering aid powder has a 50% particle size of about 5 μm, and firing the resultant assembly to thereby form a glow plug for a diesel engine.