The paper discusses experimental studies to determine the effect of the die working portion angle on the lubrication conditions, zinc coating thickness and the mechanical properties of medium-carbon steel wires. The test material was 5.5 mm-diameter wire rod which was drawn into 2.2 mm-diameter wire in seven draws at a drawing speed of v = 10 m/s. Conventional drawing dies of a working portion angle of α = 3, 4, 5, 6, 7°, respectively, were used for the drawing process. After the drawing process, the quantity of the lubricant on the wire surface and the thickness of the zinc coating were determined in individual draws. Testing the finished 2.2 mm-diameter wires for mechanical properties, on the other hand, determined the effect of the die working portion on the yield point, tensile strength, uniform and total elongation, reduction in area, the number of twists and the number of bends.
Titania dioxide (TiO2) layers were synthesized via the acid-catalysed sol-gel route using titania (IV) ethoxide, and then annealed at temperatures varying in the range of 150–700 °C. The research concerned the effect of annealing temperature on the structure of TiO2 layers, their surface morphology, and their optical properties. Further, X-ray diffractometry, and Raman spectroscopy were used to determine the structure of TiO2 layers. Scanning electron and atomic force microscopy were used to study the surface morphology of TiO2 layers. Transmittance, reflectance, absorption edge, and optical homogeneity were investigated by UV-VIS spectrophotometry, while the refractive index and thicknesses of TiO2 layers were measured using a monochromatic ellipsometer. Chromatic dispersion characteristics of the complex refractive index were determined using spectroscopic ellipsometry. Structural studies have shown that the TiO2 layers annealed at temperatures up to 300 °C are amorphous, while those annealed at temperatures exceeding 300 °C are polycrystalline containing only anatase nanocrystals with sizes increasing from 6 to 20 nm with the increase of the annealing temperature. Investigations on the surface morphology of TiO2 layers have shown that the surface roughness increases with the increase in annealing temperature. Spectrophotometric investigations have shown that TiO2 layers are homogeneous and the width of the indirect optical band gap varies with annealing temperature from 3.53 eV to 3.73 eV.
The paper describes modification to Fm3–m (space group no. 225) lattice of aluminium based α-solid solution observed in Zn-Al alloys required to properly correlate quantitative data from X-ray diffraction analysis with results obtained from quantitative scanning electron microscopy image analysis and those predicted from Zn-Al binary phase diagram. Results suggests that 14 at.% of Zn as a solute atom should be introduced in crystal lattice of aluminium to obtain correct estimation of phase quantities determined by quantitative X-ray diffraction analysis. It was shown that this modification holds for Cu mould cast as well as annealed and water-cooled samples of Zn-3wt.%. Al and Zn-5wt.% Al.
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