| 摘要 |
A coating has a cylindrical body (914) comprising upper and lower edges, and a flange extending radially outwards from the upper edge. A recess (932) is formed in an outer surface of the body. A slit (938) is arranged in the recess and passes through the body, where the body is coated by yttrium or yttrium oxide. A lip (918) extends from an inner surface of the body in a radially inward manner, where the lip has an upper surface. |
