| 摘要 |
Wire for mfr. of intra-uterine contraceptive devices (IUD's) comprises an outer layer of Cu bonded to an inner core of corrosion-resistant metal (M) by a thin diffusion layer, where M is a flexible metal more noble than Cu (pref. Pt or esp. Ag). The wire is pref. produced by forming a wire of metal M, introducing the wire into a Cu tube, and bonding the tube to the wire, pref. by drawing (''hydrostatic extrusion'') and heat treatment to form a diffusion layer at the interface between the Cu and M. The outside dia. of the composite wire is pref. 0.2-0.4 mm and the dia. of the core is pref. 10-15% of the outside dia. IUD's made of the wire have good resistance to fragmentation, even when severe corrosion of the Cu layer has occurred. |
