… heading each contain two or more elements, one of which is described by the term used (hydrogen, nitrogen, silicon or … used for lining electric ovens or for the manufacture of crucibles. Silicon nitride (Si 3 N 4 ) is a greyish‑white …
… washable and are more resistant to abrasive wear than those described in Item (i) above. Products having a poly(vinyl … have a layer of plaiting material bound by spun textile fibre. (b) Borders and friezes, being narrow strips of …
