Hot‐Pressing Magnesium Fluoride

Hot-pressing powdered magnesium fluoride resulted in a polycrystalline compact with essentially the density and transmittance of a single crystal. Compacted powdered MgF2 was heated to 650°C and held under a pressure of 30,000 psi for 15 minutes. The starting material had to be free from impurities which would form a second phase, and the presence of water and bound hydroxyl groups had to be minimized. Overheating caused the starting material to resist hot-pressing. It is postulated that mechanical bulk decrease was followed by plastic deformation during pressing and that both solid and surface diffusion of material took place to complete the coalescence of the grains.