A process of forming a sintered article, comprising: supporting a piece of inorganic material with a pressurized gas; and sintering the piece of inorganic material while supported by the pressurized gas by heating the piece of inorganic material to a temperature at or above a sintering temperature of the inorganic material such that the inorganic material is at least partially sintered forming the sintered article, wherein at least a portion of the inorganic material being sintered is not in contact with a solid support during sintering, wherein the pressurized gas is provided by a gas bearing including first and second opposing bearing surfaces defining a channel between the first and second bearing surfaces, wherein the gas bearing delivers gas to the channel through the first and second bearing surfaces, wherein supporting the piece of inorganic material comprises positioning the piece of inorganic material within the channel such that opposing first and second major surfaces of the piece of inorganic material are both supported by the pressurized gas, wherein the gas bearing applies pressure to both of the first and second major surface of the piece of inorganic material during sintering such that deformation of the first and second surfaces is resisted during sintering, and further comprising moving the piece of inorganic material through the channel from a first end of the channel to a second end of the channel during sintering, wherein the piece of inorganic material comprises a length and a width, wherein the length of the piece of inorganic material is greater than the distance between the first and second ends of the channel, wherein during sintering the density of the piece of inorganic material increases such that the density of the piece of inorganic material when located at the second end of the channel is greater than the density of the piece of inorganic material when located at the first end of the channel, wherein during sintering the width of the piece of inorganic material decreases as the piece of inorganic material moves from the first end of the channel to the second end of the channel. supporting a piece of inorganic material with a pressurized gas; and sintering the piece of inorganic material while supported by the pressurized gas by heating the piece of inorganic material to a temperature at or above a sintering temperature of the inorganic material such that the inorganic material is at least partially sintered forming the sintered article, wherein at least a portion of the inorganic material being sintered is not in contact with a solid support during sintering, wherein the pressurized gas is provided by a gas bearing including first and second opposing bearing surfaces defining a channel between the first and second bearing surfaces, wherein the gas bearing delivers gas to the channel through the first and second bearing surfaces, wherein supporting the piece of inorganic material comprises positioning the piece of inorganic material within the channel such that opposing first and second major surfaces of the piece of inorganic material are both supported by the pressurized gas, wherein the gas bearing applies pressure to both of the first and second major surface of the piece of inorganic material during sintering such that deformation of the first and second surfaces is resisted during sintering, and further comprising moving the piece of inorganic material through the channel from a first end of the channel to a second end of the channel during sintering, wherein the piece of inorganic material comprises a length and a width, wherein the length of the piece of inorganic material is greater than the distance between the first and second ends of the channel, wherein during sintering the density of the piece of inorganic material increases such that the density of the piece of inorganic material when located at the second end of the channel is greater than the density of the piece of inorganic material when located at the first end of the channel, wherein during sintering the width of the piece of inorganic material decreases as the piece of inorganic material moves from the first end of the channel to the second end of the channel.