Stepwise/ultimate density milling

Claim 1

A method of forming a slurry for casting into a ceramic sheet from predetermined quantities of an organic solvent, a solvent soluble polymeric binder material, a resin plasticizer and a ceramic particulate consisting in separated parts of aluminum oxide and glass frit, said method comprising; (a) forming a relatively low viscosity pre-mix having a viscosity in the range 2-8 cps by combining a predetermined portion of the solvent, all of the plasticizer and a predetermined portion of said binder material; (b) forming a relatively high viscosity post-mix having a viscosity in the range 3,000-30,000 cps by combining the remaining portions of said solvent and said binder material; (c) mixing the glass frit in said pre-mix; (d) dispersing the aluminum oxide in the glass frit and pre-mix mixture and forming an intermediate slurry by adding the aluminum oxide, stepwise, in predetermined portions and mixing for predetermined periods of time; and (e) combining said post-mix with said intermediate slurry.

Claim 2

A method of forming a slurry for casting into a ceramic sheet from predetermined quantities of an organic solvent, a solvent soluble polymeric binder material, a resin plasticizer and a ceramic particulate consisting in separated parts of aluminum oxide and glass frit, said method comprising; (a) forming a relatively low viscosity pre-mix having a viscosity in the range 2-8 cps by combining a predetermined portion of the solvent, all of the plasticizer and a predetermined portion of said binder material; (b) forming a relatively high viscosity post-mix having a viscosity in the range 3,000-30,000 cps by combining the remaining portions of said solvent and said binder material; (c) mixing the glass frit in said pre-mix; (d) dispersing the aluminum oxide in the glass frit and pre-mix mixture and forming an intermediate slurry by adding the aluminum oxide, stepwise, in predetermined portions and mixing for predetermined periods of time; and (e) combining said post-mix with said intermediate slurry.

Claim 3

A method of forming a ceramic slurry by milling in a ball mill selected quantities of a solvent, a polymeric binder material, a plasticizer, aluminum oxide and glass frit, said method comprising: (a) forming a pre-mix of a relatively low viscosity in the range 2-8 cps by combining a predetermined portion of the solvent, said plasticizer and a predetermined portion of said binder material; (b) forming a relatively high viscosity post-mix by combining the remaining portions of the solvent and binder material; (c) adding said pre-mix and the glass frit to said ball mill and milling to reduce the size of the frit particles; (d) adding aluminum oxide to said ball mill in a series of steps, in predetermined portions, and milling for predetermined periods of time to disperse the aluminum oxide and obtain in intermediate slurry having a high degree of aluminum oxide deagglomeration; and (e) adding said post-mix to said intermediate slurry and milling to form said ceramic slurry.

Claim 4

A method of forming a ceramic slurry by milling in a ball mill selected quantities of a solvent, a polymeric binder material, a plasticizer, aluminum oxide and glass frit, said method comprising: (a) forming a pre-mix of a relatively low viscosity in the range 2-8 cps by combining a predetermined portion of the solvent, said plasticizer and a predetermined portion of said binder material; (b) forming a relatively high viscosity post-mix by combining the remaining portions of the solvent and binder material; (c) adding said pre-mix and the glass frit to said ball mill and milling to reduce the size of the frit particles; (d) adding aluminum oxide to said ball mill in a series of steps, in predetermined portions, and milling for predetermined periods of time to disperse the aluminum oxide and obtain in intermediate slurry having a high degree of aluminum oxide deagglomeration; and (e) adding said post-mix to said intermediate slurry and milling to form said ceramic slurry.

Claim 12

A method of forming a slurry for casting into ceramic substrates starting from selected quantities of a solvent, plasticizer, polymeric binder, powdered aluminum oxide and frit, said method comprising: (a) forming a pre-mix by combining about 50% of the solvent, all of the plasticizer and about 25% of the binder; (b) forming a post-mix by combining the remaining quantities of solvent and said binder; (c) mixing the pre-mix and frit in a ball mill; (d) adding to the mixture of frit and pre-mix a first portion of about 50% of said aluminum oxide and milling for a first period of about 1.25 hours forming a first resultant mixture, adding a second portion of about 50% of the remaining aluminum oxide to said first resultant mixture and milling for about an hour forming a second resultant mixture and adding a third portion consisting of the remaining aluminum oxide to said second resultant mixture and milling for about 2 hours to form a third resultant mixture whereby said first portion of aluminum oxide is milled to near complete deagglomeration for a total time of about 4.25 hours, said second portion of aluminum oxide is milled to about 50%-60% deagglomeration for a total time of about 3 hours and said third portion is milled to about 30%-40% deagglomeration; and (e) combining said third resultant mixture and said post-mix.

Claim 13

A method of forming a slurry for casting into ceramic substrates starting from selected quantities of a solvent, plasticizer, polymeric binder, powdered aluminum oxide and frit, said method comprising: (a) forming a pre-mix by combining about 50% of the solvent, all of the plasticizer and about 25% of the binder; (b) forming a post-mix by combining the remaining quantities of solvent and said binder; (c) mixing the pre-mix and frit in a ball mill; (d) adding to the mixture of frit and pre-mix a first portion of about 50% of said aluminum oxide and milling for a first period of about 1.25 hours forming a first resultant mixture, adding a second portion of about 50% of the remaining aluminum oxide to said first resultant mixture and milling for about an hour forming a second resultant mixture and adding a third portion consisting of the remaining aluminum oxide to said second resultant mixture and milling for about 2 hours to form a third resultant mixture whereby said first portion of aluminum oxide is milled to near complete deagglomeration for a total time of about 4.25 hours, said second portion of aluminum oxide is milled to about 50%-60% deagglomeration for a total time of about 3 hours and said third portion is milled to about 30%-40% deagglomeration; and (e) combining said third resultant mixture and said post-mix.