The optimal conditions on the plasma-forming gas fiowrate,discharge current andvoltage,distance between the plasma-torch nozzle and the metal plate surface for the processof penetration in and vaporization of steel plates by the contracted electric-arc air plasma torchaccompanied by water quenching,were determined.The X-ray structural and phase studies aswell as M5ssbauer and electron microscope studies on the samples treated were performed.Itwas demonstrated that the vaporized elemental iron was oxidized by the oxygen present in the airplasma jet to form iron oxides (wiistite,magnetite,hematite),which,depending on their mass ra-tios,determined the color of the iron oxide pigments,namely,beginning from light yellow,throughdeep yellow,light brown,deep brown,violet,red-violet,to black.A high degree of dispersity ofthe iron oxides is thus produced,with an averaged diameter of the particles below 500 nm,andtheir defective crystal structure form the basis of their potential application as components ofiron-containing catalysts and pigments.
展开▼
