ICP-AES DETERMINATION OF ALLOYING ELEMENTS IN Nb – Si BASED COMPOSITES

Abstract

At present, high-temperature composites of the Nb-Si-system are the most promising for use as High-temperature composites of Nb – Si-system are among the most promising materials to be used as heat-resistant structural materials and as an alternative to high- temperature nickel-based alloys that have largely exhausted their ability to increase the operating temperature. The next generation of high-temperature materials for casting blades of gas turbine engines should provide a temperature of about 1350°C or higher which can significantly improve the efficiency of engines and contribute to their environmental performance. Nb – Si composites are obtained by traditional methods of ingot production and powder metallurgy. Statutory regulations impose heavy demands on the chemical composition of aviation materials used for manufacturing heavy-duty parts of gas turbine engines. We present a technique for determination of the alloying elements Si, Ti, W, Mo, Hf, Cr, and Al in advanced high-temperature Nb – Si based composite materials (CM) using inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and microwave sample preparation. Conditions of sample dissolution, method of calibration line construction, and analytical lines free of significant spectral overlapping are specified to determine all the alloying elements of Nb – Si-based composites. To assess the metrological characteristics of the developed technique we used model solutions of Nb – Si composites prepared from state standard reference sample of solutions of ions of the elements. The repeatability of the technique does not exceed 1% rel., the intermediate precision does not exceed 3% rel.