Composite material and method of producing the same
There is provided a strengthened composite material that is able to improve yield, handling, and reliability when it is applied to members of semiconductor manufacturing apparatus. Five to 60 mol % ZrO 2 is contained relative to Y 2 O 3 , and temperature after a sintering process is maintained between 1,200° C. to 1,500° C. for 5 minutes or longer or temperature falling speed to reach 1,200° C. is adjusted to 200° C./h or slower, thereby producing the composite material containing, as major crystalline phases, a Y 2 O 3 solid solution in which ZrO 2 is dissolved in Y 2 O 3 and a ZrO 2 solid solution in which Y 2 O 3 is dissolved in ZrO 2 .
1. A composite material used for members of semiconductor manufacturing apparatus, comprising: major crystalline phases of an yttrium-oxide (Y 2 O 3 ) solid solution in which zirconium oxide (ZrO 2 ) is dissolved in yttrium oxide and a zirconium-oxide solid solution in which the yttrium oxide is dissolved in the zirconium oxide.
2. The composite material according to claim 1 , wherein a proportion of a zirconium oxide content to an yttrium oxide content is between 5 to 60 mol %.
3. The composite material according to claim 1 , wherein an average crystal grain size of the zirconium-oxide solid solution is larger than that of the yttrium-oxide solid solution.
4. The composite material according to claim 1 , wherein crystal grains 1 μm or less in grain size of the zirconium-oxide solid solution are dispersed in some crystal grains of the yttrium-oxide solid solution.
5. The composite material according to claim 1 , wherein three-point bending strength is 250 MPa or above.
6. The composite material according to claim 1 , wherein fracture toughness is 1.3 MPa·m 1/2 or above.
7. The composite material according to claim 1 , wherein porosity is 5% or below.
8. A method of producing the composite material according to claim 1 , comprising: a sintering step of sintering mixed powder of the yttrium oxide and the zirconium oxide at a sintering temperature of 1,400° C. to 1,850° C.; and an annealing step of maintaining temperature falling after the sintering step between 1,200° C. and 1,500° C. for 5 minutes or adjusting a temperature falling speed to reach 1,200° C. to 200° C./h or slower.