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The Hazards of Thermal-Spraying Tungsten Carbide Powder

Thermal spraying tungsten carbide powder involves a process where it is melted or heated electrically or chemically. Tungsten carbide, a commonly-used metal for coating tools in the mining and diamond industries, razor blades and a variety of sports equipment, is ideal for thermal spraying because of its hardness and its resistance to high temperatures. Exposure to tungsten carbide carries some hazards because it is toxic, particularly when ingested or inhaled. Proper precautions should be taken to avoid exposure to tungsten carbide and its dust or mist.

  1. Inhalation

    • Exposure to tungsten carbide powder through inhalation can cause asthma due to the presence of nickel and chromium. Inhalation of tungsten carbide powder can also result in a respiratory condition called hard metal lung disease. These conditions can result from both long- and short-term exposures. Inhaling large amounts of tungsten carbide and cobalt concentrations has been shown to increase risk of lung cancer. If dust is inhaled, move to an area where you can breathe fresh air and seek medical attention. When spraying tungsten carbide powder you should use an National Institute for Occupational Safety and Health (NIOSH) approved respirator for dust and mists and work in well-ventilated areas.

    Ingestion

    • Tungsten carbide powder is classified as toxic, which means serious health problems can result if the mist, powder or dust is ingested. If you ingest tungsten carbide powder, whether directly or due to unwashed hands, contaminated drinks or food, drink large amounts of water, induce vomiting and get medical attention immediately.

    Skin and Eyes

    • Due to the presence of cobalt in tungsten carbide powder, it can be an extreme irritant to skin and eyes. Sensitive skin may have an allergic reaction. If tungsten carbide powder gets into your eyes or contacts your skin, flush thoroughly. If irritation continues or a rash occurs, seek medical attention immediately. Avoid dust inhalation and direct skin contact with the dust when spraying by wearing gloves and protective goggles. When working with tungsten carbide powder you should always wash hands before eating and wash exposed skin when you are through spraying. Full body protective clothing is also recommended and all work clothing should be changed and cleaned daily.

    Reactivity

    • Although rare, tungsten carbide powder may be explosive or flammable under certain circumstances. If fire occurs, avoid inhaling smoke or fumes. Tungsten carbide powder may react with strong oxidizers, creating a fire or explosion hazard. It should be kept separate from acids and bases. Fine powders may also be flammable under some conditions. Tungsten carbide powder will react violently with fluorine, chlorine trifluoride, nitrogen oxide, iodine pentafluoride, lead dioxide, nitrogen dioxide and nitrous oxide.

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