Articles having a hardness equivalent to 9 or more on the Mohs scale.

69.09 Ceramic wares for laboratory, chemical or other technical uses; ceramic troughs, tubs and similar receptacles of a kind used in agriculture; ceramic pots, jars and similar articles of a kind used for the conveyance or packing of goods (+). - Ceramic wares for laboratory, chemical or other technical uses : 6909.11 - - Of porcelain or china 6909.12 - - Articles having a hardness equivalent to 9 or more on the Mohs scale 6909.19 - - Other 6909.90 - Other This heading covers a range of very varied articles usually made fiom vitrified ceramics (stoneware, porcelain or china, steatite ceramics, etc.), glazed or unglazed. It does not, however, cover refractory goods of a kind designed for resisting high temperatures as described in the General Explanatory Note to sub-chapter I. But articles of a type not designed for high tern erature work remain in this headin even if made of refiactory materials (e.g., thread guiif'es, grinding apparatus, etc., of sintered umina). The heading covers in particular : (I) Laboratory wares (e.g., for research or industrial use) such as crucibles and crucible lids, evaporating dishes, combustion boats, cu els; mortars and pestles; spoons for acids, spatulas; supports for filters and catalysts; lter plates, tubes, candles, cones, funnels, etc.; water-baths; beakers, graduated vessels (other than graduated kitchen measures); laboratory dishes, mercury troughs; small tubes (e-g., combustion tubes, including analysis tubes for estimation of carbon, sulphur, etc.). f (2) Ceramic wares for other technical uses, such as pumps, valves; retorts, vats, chemical baths and other static containers with single or double walls e.g., for electro lating, acid storage); taps for acids; coils, fractionating or distillation coi s and columns, l!aschig r i n r for petroleum fractionating a paratus; ding apparatus and balls, etc., for grinding mil s; des for textile rnac inery an dies for extruding man-made textiles; plates, sticks, tips thread an the like, for tools. 'Y l f- I (3) Containers of the kinds used for the commercial transport or packing of goods, e. large containers, carboys, etc., for the transport of acids and other chemical products; %igons, jars and pots, for foodstuffs (jam, condiments, meat pastes, liqueurs, etc.), for pharmaceutical products or cosmetics (pomades, ointments, creams, etc.), for inks, etc. (4) Troughs, tubs and similar containers of the type used in agriculture. The heading excludes : (a) Articles of heading 68.04. (b) Retorts, crucibles, muffles, cupels and other similar articles of refractory materials (heading 69.03). (c) Kitchen or domestic containers (e.g., tea caddies, bread bins, biscuit barrels) (heading 69.11 or 69.12). (d) General purpose jars and containers for laboratories and display jars for pharmacies, confectioners, etc. (heading 69.14). (e) Articles of cermets (heading 81.13). (9 Electrical apparatus (switches, junction boxes, fuses, etc of headings 8533 to 85.38, and electrical insulators, mulating fittings, etc., of heading 85.46 or 8247.

Subheading Explanatory Note. Subheading 6909.12 This subheading covers high:perfo~pince ceramic articles. These articles are composed of a crystalline ceramic matrix (e.g., of alumna, sillcon carbide, zirconla, or mtrides of silicon, boron or aluminium, or of combinations thereoq; whiskers or fibres of reinforcing material (e.g., of metal or graphite) may also be dispersed in the matrlx to form a composite ceramic rnatenal. These articles are characterized by a matrix which has a very low porosity and in which the grain size is very small; by high resistance to wear, corrosion, fatigue and thermal shock; by high-temperature strength; and by strength-to-weight ratios comparable to or better than those of steel. They are often used in place of steel or other metal parts in mechanical applications requirin close dimensional tolerances (e-g., engine turbocharger rotors, rolling contact bearings and machine tool3. The Mohs scale mentioned in this subheading rates a material by its abilit to scratch the surface of the material below it on the scale. Materials are rated fiom 1 (for talc) to l g (for diamond). Most of the high-performance ceramic materials fall near the top of the scale. Silicon carbide and aluminium oxide, both of which are used in high-performance ceramics, fall at 9 or above on the Mohs scale. To distinguish among harder materrals, the Mohs scale is sometimes expanded, with talc as 1 and diamond as 15. On the expanded Mohs scale, fused alumina has a hardness equvalent to 12, and silicon carbide has a hardness equivalent to 13.