Ceramic classification under Chapter 69 prevails for silicon carbide DPF bricks over machinery parts heading.

Raw silicon carbide bricks used for diesel particulate filter application are classifiable under Tariff Item 6902 20 40 as refractory ceramic bricks, because they are fired ceramic articles specifically covered by Chapter 69 and classified by constituent material. Although intended for DPF use after coating and canning, they remain excluded from Heading 8421, since Chapter Note 1(b) to Chapter 84 excludes ceramic machinery parts and the explanatory notes classify filtering elements by material. The more specific tariff description in Heading 6902 therefore prevails over the broader machinery heading, and the goods are not classifiable as parts of particulate filters.

---

---

Issues: Whether raw silicon carbide bricks for DPF application are classifiable under Tariff Item 6902 20 40 of the Customs Tariff Act, 1975 or under Heading 8421 as parts of particulate filters.

Analysis: The product was found to be a ceramic/refractory article based on silicon carbide and intended for DPF use only after further coating and canning. Chapter Note 1 to Chapter 69 applies to ceramic products fired after shaping, and the material and process described satisfied that requirement. Heading 6902 specifically covers refractory bricks and shapes, including silicon carbide bricks and shapes, even where they are recognisable as intended for machinery of Section XVI. Chapter Note 1(b) to Chapter 84 excludes ceramic machinery and ceramic parts, and the explanatory notes state that filtering elements are classified according to their constituent material. The interpretative rule preferring the most specific description also supported classification under Heading 6902 over Heading 8421.

Conclusion: Raw silicon carbide bricks for DPF application are classifiable under Tariff Item 6902 20 40 and not under Heading 8421.

Ratio Decidendi: Where a ceramic article is specifically covered by Chapter 69 and classified according to its constituent material, it is excluded from Chapter 84 even if it is intended for use in machinery as a part or element.

---