Surface Strengthening Of Double Glow Plasma Carbon And Copper Alloying On Zirconium

Zirconium has become an ideal material for the nuclear industry, aviation andchemical, because of a small absorption cross section of thermal neutron and uniqueradiation resistant. However, lower hardness and wear-resisting performance has aninfluence on application. Based on double glow plasma alloying technology in purezirconium surface preparing C、Cu alloying layer, which is metallurgical bonding andcomposition distribution with gradient characteristics, in order to improve its corrosionresistance and wear resistance.The effective processing parameters as follows, Permeability copper: processingtemperature860-900℃, the time4h, work pressure45Pa, source voltage870-920V,cathode voltage360-400V, distance between source and cathode15mm. carburizing:processing temperature950-980℃, the time4h, work pressure35Pa, source voltage940-980V, cathode voltage400-450V, distance between source and cathode10mm; Weget a thickness to45μm Zr-Cu alloy layer and a thickness to12μm Zr-C alloy layer.The pure zirconium’s friction coefficient and wear scar have nothing to change aftergetting a Zr-Cu alloy layer, wear quantity does the same. After quenching process, due tothe organization of the refining reinforcement, the surface hardness increased, grindingcrack necked, wear resistance has been based on the permeability were increased.Aftercarburizing treatment, the friction coefficient of zirconium reduced nearly half, whichshows the friction and wear resistance is improved, and wear quantity reduce4times,owning an obviously smaller wear scar, the hardness and brittleness of zirconium haveincreased that make a wider wear scar and a smaller wear quantity. The corrosionresistance of ally layer were investigated in this paper. In NaCl and NaOH solution,zirconium carburizing and zirconium penetrative copper have improved in corrosionresistance: there is an obvious passivation area after zirconium copper case and corrosioncurrent and passivation current and corrosion rate has dropped considerably; in zirconiumcarburizing, passivation current and corrosion speed decreases, passivation area becamewider. Quenched specimens make the corrosion resistance stronger. The corrosionresistance of samples get nothing improved in H₂SO₄, including their quenched specimens,for the pure zirconium’s superior corrosion resistance.