| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a noncontact type seal ring small in deformation, capable of keeping a flow rate constant and highly reliable. <P>SOLUTION: The noncontact type seal ring 1 includes a fixed ring 2 and a rotating ring 3, wherein respective end faces 2a, 3a are arranged opposite to each other via a gap S into which fluid F is supplied. In the noncontact type seal ring 1, the rotating ring 3 is made of ceramics in which a content of silicon nitride is 81.8 mass% or more, and the ceramics contains aluminum oxide, magnesium oxide and calcium oxide. To the total of 100 mass% of aluminum oxide, magnesium oxide and calcium oxide, the contents of aluminum oxide and magnesium oxide are from 12 mass% to 22 mass% and from 20 mass% to 33 mass%, respectively, and the remainder is calcium oxide. An average crystal grain size of silicon nitride is 12μm or less (however, except 0μm). <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
