Explanatory notes
… 28.52 . The heading covers, for example, calcium, barium, zinc, manganese, aluminium, cobalt, chromium, lead, etc., … (18) Getters for vacuum tubes , with a basis of barium, zirconium, etc. These getters are usually put up in … also includes dental zirconia products with a basis of zirconium oxide (ZrO 2 ) and other metal oxides. They can …