What are the hazards of radioactive elements in the thermal spraying process?

       In the past plasma arc process, the spray gun has used thoriated tungsten material for the cathode. Thorium is a natural radioactive substance that undergoes a spontaneous decay process and emits alpha, beta, and gamma rays (alpha rays account for 90%; beta rays account for 9%; gamma rays account for 1%). In the process of plasma spraying, the radiation energy and dose of thorium are very low. When the distance from the thorium tungsten electrode is only 10mm to 20mm, paper, cloth, etc. can completely absorb all the particles. Therefore, the radioactivity of thorium depends on the penetration of the external radiation caused by the very small effect, which can be ignored.



     Now the cathode of the spray gun is changed to cerium tungsten material, and its alpha emission aerosol concentration can be reduced by hundreds of times, and there is basically no radioactivity. So there is no such danger.