| 摘要 |
This PG-coated product (14) is produced by producing a body (11) by using PBN, providing traceability indication (12) made of purified graphite in an arbitrary section of the body surface; and covering the body surface including the traceability indication with a PG coat (13). By setting the thickness of the PG coat to 100 µ m or less, preferably 80 µ m or less, it is possible to provide transparency sufficient for reading the product serial number marked on the body surface. This is a suitable way of marking the traceability. Because graphite does not adversely affect the physical properties of PBN and PG, the function and durability intrinsic to the product will not be impaired even when the graphite traceability is placed between the PBN body surface and the PG coat. Further, producing a PBN-overcoated product (24) by covering the surface of a body (21), having traceability indication (22) of purified graphite, with a PBN film (23) having a thickness of 700 µ m or less, preferably 500 µ m or less, is also a suitable way of marking the traceability. |
