| 摘要 |
<p>An expendable substrate which in use contacts molten metal, for example a foundry mould or core or ladle lining, is coated with a coherent layer of refractory particles by tribo-electrically charging refractory particles coated with an organic binder, the coated particles having an electrical resistivity of at least 1010 ohm. cm. at 10kv, earthing the substrate and bringing the charged particles into contact with the earthed substrate. Suitable binders are thermoplastic resins, thermosetting resins and waxes and the quantity of binder in the binder coated particles is usually less that 10% by weight. </p> |
