The paper deals with susceptibility of nodular cast iron with ferritic -pearlitic matrix on cavitation erosion . Cavitation tests were carried out with the use of a cavitation erosion vibratory apparatus employing a vibration exciter operated at frequency of 20 kHz. The study allowed to determine the sequence of subsequent stages in which microstr ucture of cast iron in superficial regions is subject to degradation. The first features to be damaged are graphite precipitates. The ferritic matrix of the alloy turned out to be definitely less resistant to cavitation erosion compared to the pearlitic matrix component.

Ultratrace analysis requires the use of extremely clean reagents, including water. Quality of water used in laboratories is crucial element of obtained reliable results. In chemical and biological laboratories, as well as industry, distilled, re-distilled and deionized waters arc used. Important factor of waler quality is the content of inorganic ions. One ofthe most competitive analytical techniques for trace analysis of inorganic anions and cations is ion chromatography. In the work ion chromatographic method for the determination of common inorganic anions (fluoride, chloride, nitrate, phosphate and sulfate) and cations (lithium, sodium, ammonium, potassium, magnesium and calcium) in distilled, re-distilled and deionized water has been developed and validated.