Aluminum oxide (Al2O3), also known as alumina, corundum, sapphire, or ruby, is one of the best insulators used in a wide range of applications: in electronic components, as a support material for catalysts, or as a chemically resistant ceramic, to name a few. Aluminum oxide (Al2O3), also known as alumina, corundum, sapphire, or ruby, is one of the best insulators used in a wide range of applications: in electronic components, as a support material for catalysts, or as a chemically resistant ceramic, to name a few. Analytical Chemistry Materials Science Phys.org – latest science and technology news stories