The aim of the paper is to study the effect of zinc addition on the corrosion behavior of Ca65–xMg17.5Zn17.5+x (x = 0, 2.5, 5 at.%) alloys in simulated physiological fluids at 37°C. The electrochemical measurements allowed to determine a corrosion potential, which showed a positive shift from –1.60 V for Ca65Mg17.5Zn17.5 alloy to –1.58 V for Ca60Mg17.5Zn22.5 alloy, adequately. The more significant decrease of hydrogen evolution was noticed for Ca60Mg17.5Zn22.5 alloy (22.4 ml/cm2) than for Ca62.5Mg17.5Zn20 and Ca65Mg17.5Zn17.5 samples (29.9 ml/cm2 and 46.4 ml/cm2), consequently. The corrosion products after immersion tests in Ringer’s solution during 1 h were identified by X-ray diffraction and X-ray photoelectron spectroscopy as calcium, magnesium oxides, carbonates, hydroxides and calcium hydrate.
The surface properties of particles emitted from six selected coal-fired power and heating plants in Poland have been studied in this work for the first time. Samples were collected beyond the control systems. Surface composition of the size-distributed particles was obtained by photoelectron spectroscopy (XPS). The reflection of the smallest, submicron particles was also measured to calculate their specific/mass absorption. The surface layer of the emitted particles was clearly dominated by oxygen, followed by silicon and carbon. The sum of the relative concentration of these elements was between 85.1% and 91.1% for coarse particles and 71.8–93.4% for fine/submicron particles. Aluminum was typically the fourth or fifth, or at least the sixth most common element. The mass absorption of the submicron particles emitted from the studied plants ranged from 0.02 m2g-1 to 0.03 m2g-1. Only specific absorption obtained for the “Nowy Wirek” heating plant was significantly higher than in other studied plants probably because the obsolete fire grate is used in this heating plant. The obtained results suggest that the power/heating-plant-emitted fine particles contain less carbonaceous material/elemental carbon on their surfaces than those that are typical in urban air.