Huber | Martinswerk Specialty Aluminas With the acquisition of Martinswerk GmbH in February 2016, Huber Engineered Materials is a global supplier of specialty alumina products. Martoxid® calcined alumina products are high density, hard products available in a wide variety of particle size distributions. A variety of Martoxid grades are available and recommended to produce polishing and lapping compounds, ceramics and thermally conductive compounds. Compalox® activated alumina products are high surface area materials used in chemical processing applications to remove impurities and can also act as a feedstock or catalyst. Click on one of the icons below to find out more about our specialty alumina solutions.