The Invention of Hard Metals

The next important milestone in the chronology of the development of doped tungsten wires is 1923, which marked the year when K. Schröter, chief engineer of the OSRAM research group in Berlin, Germany, made a cemented carbide or hard metal by combining tungsten carbide (WC) and cobalt powder through mixing, pressing and liquid-phase sintering.

From a historical perspective, William D. Coolidge's development PM process and tool "for making tungsten ductile" in 1909 marked the beginning of the use of tungsten filaments in the lighting industry. William D. Coolidge's development of the PM process and tools to "make tungsten ductile" in 1909 marked a breakthrough in the use of tungsten filaments in the lighting industry and began the modern industrial era of Powder Metallurgy.

The Coolidge Process

William D. Coolidge (1873-1975), Figure 8, began his career at GE's research laboratory in September 1905. Interestingly, Coolidge's first task was to investigate the cause of the rapid breakage of the filament of the German tantalum lamp when operating under alternating current, most likely due to the limitations of the lamp's cavity technology and the residual gas in the bulb.

In recent years, tungsten rings have been a popular choice for their durable and scratch-resistant properties. However, they can also lose their luster over time. Below, we will explain how to take care of your tungsten wedding ring.