"高铝陶瓷" can be translated into English as "high-alumina ceramic" or "high-aluminum ceramic".
Both expressions are commonly used, with "high-alumina ceramic" being slightly more prevalent in technical and industrial contexts, as "alumina" is the technical term for aluminum oxide ($Al_2O_3$), the primary component of high-alumina ceramics. However, "high-aluminum ceramic" is also understandable and used in some contexts.