6.C.6.High-temperature ceramic materials as follows:

a. Bulk machinable silicon-carbide reinforced unfired ceramic usable for nose tips usable in systems specified in 1.A. or 19.A.1.;
b. Reinforced silicon-carbide ceramic composites usable for nose tips, re-entry vehicles, nozzle flaps, usable in systems specified in 1.A. or 19.A.1.;
c. Bulk machinable ceramic composite materials consisting of an 'Ultra High Temperature Ceramic (UHTC)' matrix with a melting point equal to or greater than 3000°C and reinforced with fibres or filaments, usable for missile components (such as nose-tips, re-entry vehicles, leading edges, jet vanes, control surfaces or rocket motor throat inserts) in the systems specified in 1.A., 19.A.1. or 19.A.2.
Note:
Item 6.C.6.c. does not control 'Ultra High Temperature Ceramic (UHTC)' materials in non-composite form.
Technical Note:
'Ultra High Temperature Ceramics (UHTC)' includes:
1. Titanium diboride (TiB2);
2. Zirconium diboride (ZrB2);
3. Niobium diboride (NbB2);
4. Hafnium diboride (HfB2);
5. Tantalum diboride (TaB2);
6. Titanium carbide (TiC);
7. Zirconium carbide (ZrC);
8. Niobium carbide (NbC);
9. Hafnium carbide (HfC);
10. Tantalum carbide (TaC).