Rensselaer Semi-Weekly Republican, Volume 41, Number 124, Rensselaer, Jasper County, 26 November 1909 — HARDER THAN THE DIAMOND. [ARTICLE]

HARDER THAN THE DIAMOND.

Metallic Tantalum Drawn Into Wire or Rolled Into Sheets. [ That nothing is harder in nature than a diamond and that a diamond alone can cut a diamond, le a popular belief of long standing, says an exchange. Yet thqre Is something, harder. A new substance has made Its apearance which, If It cun be obtained in sufficient quantity, will probably replace the diamond alike In the operations of drill boring and in the lapidary’s workshop, for it is harder than diamond; so hard, in fact, that the only effect produced by a diamond drill, worked day and night for three days on a sheet of the substance one twenty-fifth of an inch thick, with a speed of 5,000 revolutions a minute, was a slight dint In the sheet and the wearing out of tne diamond. This substance is pure metallic tantalum. Tantalum is not a common metal, yet it is also not of the rarest, its existence was discovered more than a century ago. , Pure tantalum was first prepared by Dr, Bolton. One of hL methods Is to fuse the double fluoride Of potassium and tantalum with metallic potassium in an elctric furnace in vacuc bi t he seems to prefer a much simplex electrical method. Making up the oxide wdth a filament, exactly like that of a Nernst Incandescent lamp, he places it in a globe connected to an air pump and turns on the current. The oxide is decomposed and th© oxygen being gradually removed by the pump the filament is reduced to the metallic state. ’ Tantalum differs from all other known substances In combining extreme hardness with extreme ductility. When red hot It Is easily rolled into bars and sheets drawn into wire. It is scarcely affected by the oxygen of the air, even at red heat, and not at all at ordinary temperature, and tne strongest acids fail to dissolve it; nor does it amalgamaLg, with mercury. It melts only at the highest attainable temperatures and is therefore 'well fitted to serve for filaments in incandescent lamps, being much stronger than carbon. A pound or it will make 20,000 lamps, and these require exectly half as much power to light them as do carbon filaments giving the same brilliancy. If it can only be produced in sufficient quantity, tanta,um should prove a most useful metal. it~wl7r"furnleh better boring tools than the diamond drill and cheaper electric lights than carbon, while the possible uses ot a plate or a wire harder than diamond and yet tough and strong, a-e almost infinite, for every other hard substance is brittle, and this fact has hampered the engineer for centuries.