The first written record of alum, made by Greek historian Herodotus, dates back to the 5th century BCE although the nature remained unknown. In 1754, German chemist Andreas Sigismund Marggraf synthesized alumina by boiling clay in sulfuric acid and subsequently adding potash, a mixture of various mined and manufactured salts that contain potassium in water-soluble form.
In 1889, Austrian chemist Carl Joseph Bayer discovered a way of purifying bauxite to yield alumina, now known as the Bayer process. Prices of aluminum dropped and it became widely used in jewelry, everyday items, eyeglass frames, optical instruments, tableware, and foil in the 1890s and early 20th century. During World War I, major governments demanded large shipments of aluminum for light strong airframes.
Aluminum metal has an appearance ranging from silvery white to dull gray, depending on the surface roughness. In most applications various alloys are used instead of pure because of their higher strength and hardness. It’s easily machined and an excellent thermal and electrical conductor, having 59% the conductivity of copper while only having 30% of the density.
Anodizing is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts, thereby increasing the resistance to corrosion and wear while also providing a better adhesion for paint primers. Aluminum is strong, extremely lightweight, and available in many different colors so you’re certain to find the perfect pen or pencil.