METHOD OF MAKING A CERAMIC COMPOSITE MATERIAL BY COLD SINTERING
Ceramic composite materials, devices and methods are shown. In selected examples, ceramic materials are processed at low temperatures that permit incorporation of low temperature components, such as polymer components. manufacturing methods include, but are not limited to, injection molding, autoclaving and calendaring.
1 . A method of forming a sintered ceramic composite component, comprising:
placing an amount of powder, including a cold sinterable ceramic powder in a die;
placing an amount of polymer or polymer precursor molecules in the die;
applying an activating solvent for the powder in the die;
heating to a first temperature, and applying sufficient pressure to the powder, amount of polymer or polymer precursor molecules, and solvent to activate sintering of the powder; and
heating to a second temperature to anneal a polymer phase of the sintered ceramic composite component.
2 . The method of claim 1 , wherein the second temperature is equal to or greater than a glass transition temperature of an amorphous polymer phase.
3 . The method of claim 1 , wherein the second temperature is equal to or greater than a melting temperature of a semi-crystalline polymer phase.
4 . The method of claim 1 , further including holding the sintered ceramic composite component at pressure while cooling to room temperature.
5 . The method of claim 1 , wherein the polymer phase includes polyetherimide (PEI).
6 . The method of claim 5 , wherein the cold sinterable ceramic powder includes zinc oxide.
7 . The method of claim 6 , wherein applying sufficient pressure to the powder includes applying pressure less than or equal to 500 MPa.
8 . The method of claim 7 , wherein heating to the first temperature includes heating to a temperature no greater than 200° C. and above a boiling point of the activating solvent.
9 . The method of claim 8 , wherein heating to the second temperature includes heating to a temperature between about 220 and 260° C.
10 . The method of claim 6 , wherein placing the amount of polymer or polymer precursor molecules in the die includes placing an amount of polymer or polymer precursor molecules to yield a 20%-50% by volume fraction of polymer in the sintered ceramic composite component.
11 . The method of claim 1 , further including drying the amount of powder before sintering.
12 . The method of claim 1 , further including drying the sintered ceramic composite component after sintering.
13 . The method of claim 1 , wherein placing the amount of powder, including a cold sinterable ceramic powder in a die includes placing powder with an average diameter smaller than 30 μm.
14 . The method of claim 1 , wherein multiple components are stacked within a single die and sufficient heat and pressure are applied to the multiple components concurrently.