Thorium tungsten rod is a tungsten alloy bar containing 2% thorium oxide, known for its excellent high-temperature strength, resistance to electron emission, and thermal stability. 

The black surface of black tungsten wire is mainly because graphite emulsion is sprayed during the drawing process. As a lubricant, graphite emulsion can effectively reduce the friction coefficient between the tungsten wire and the drawing die, reduce the risk of tungsten wire breakage during the drawing process, and extend the service life of the drawing die. After the graphite emulsion adheres to the surface of the tungsten wire, a thin black coating will be formed, which is also the source of the appearance characteristics of black tungsten wire. The graphite layer can be removed by alkaline washing.

Cleaned Tungsten Wire, also known as white tungsten wire, does not refer to tungsten wire with a white surface, but refers to tungsten wire that has been electrolytically washed and polished. The surface of this tungsten wire is smooth and clean, without graphite emulsion attached, and presents a silver-gray metallic luster.

In the photovoltaic field, tungsten wire is generally used as a diamond wire base material for silicon wafer cutting. It has high toughness, high tensile strength, high temperature resistance, corrosion resistance and other characteristics. Compared with traditional high-carbon steel wire, tungsten wire has great potential for wire diameter refinement. At present, the diameter of tungsten wire used in diamond wire saws in the photovoltaic industry is about 25-35μm, which is only half the diameter of an adult hair. The diameter of high-carbon steel wire is usually 30-60μm. Wire diameter refinement can effectively reduce silicon wafer loss, meet the requirements of large-size and thin silicon wafer cutting, and help the photovoltaic industry reduce costs and increase efficiency.