Sintered yttrium oxide body of large dimension

A process of making a sintered yttrium oxide body, the process comprising the steps of:

• a. disposing yttrium oxide powder inside an inner volume defined by a spark plasma sintering tool, wherein the spark plasma sintering tool comprises:
• a die comprising a sidewall comprising an inner wall and an outer wall, wherein the inner wall has a diameter that defines the inner volume;
• an upper punch and a lower punch operably coupled with the die, wherein each of the upper punch and the lower punch have an outer diameter that is less than the diameter of the inner wall of the die thereby creating a gap between each of the upper punch and the lower punch and the inner wall of the die when at least one of the upper punch and the lower punch are moved within the inner volume of the die, wherein the gap is from 10 μm to 70 μm wide and creating vacuum conditions inside the inner volume;
• b. applying a pressure of from 10 MPa to 60 MPa to the yttrium oxide powder by moving at least one of the upper punch and the lower punch within the inner volume of the die to apply pressure to the yttrium oxide powder while heating to a sintering temperature of from 1200 to 1600° C. and performing sintering to form a sintered yttrium oxide body;
• and
• c. lowering the temperature of the sintered yttrium oxide body, wherein the yttrium oxide powder of step a) has a surface area of 10 m2/g or less, wherein the sintered yttrium oxide body has a total impurity level of 40 ppm or less, a density of not less than 4.98 g/cm3, at least one surface comprising at least one pore, wherein of all pores on the at least one surface no pore is larger than 5 μm in diameter.