| Silicon Oxide | Aluminum Oxide | Magnesium Oxide |
| Titanium Oxide | Zirconium Oxide |
| 3M | Advanced Ceramics Limited | H.C. Starck |
| Imerys (Kentucky-Tennessee Clay Co.) | Indium Corporation of America | MarkeTech |
| NAPCO | Pyrotek, Inc. | Sharadaa Ceramics |
| Sphere One Inc | Thermoseal Inc. | UBE |