UDC 546.65+621.384.83 SPECIAL FEATURES OF ANALYSIS AND CONTROL OF CONCENTRATION INHOMOGENEITY OF COMPLEXLY MODIFIED INDUSTRIAL MATERIALS BY THE METHOD OF SECONDARY-ION MASS SPECTROMETRY A. A. Anikin, 1 S. B. Venig, 1 and A. G. Zhukov 1 Translated from Metallovedenie i Termicheskaya Obrabotka Metallov , No. 7, pp. 69 – 72, July, 2018. Concentration inhomogeneity in iron-carbon alloys is analyzed and controlled. It is shown that application of secondary-ion mass spectrometers with about 200 resolution with respect to the mass numbers and a compara- tively large diameter of the primary ion beam (1 – 2 mm) gives results required for development and control of processes of structure formation in modified alloys and of changes in their physical and mechanical pro- perties. Key words: alloys, modification, inhomogeneity, analysis, control, mass spectrometry. INTRODUCTION Development of processes of production of novel comp- lexly modified industrial materials including heat treatment may be accompanied by uncontrolled redistribution of che- mical elements and their compounds. This redistribution re- sults in formation of concentration inhomogeneity, which may change the physical, mechanical and operating proper- ties of the materials. In this connection, analysis and control of such inhomogeneity may be decisive for determining the field of application of such materials. The method of secon- dary-ion mass spectrometry (SIMS) offers many possibilities in this respect. The aim of the present work was to study the process of modification of iron-carbon alloys and to create methods for its control with the use of secondary-ion mass spectrometry. METHODS OF STUDY We studied the distribution of retained yttrium over the volume of yttrium cast iron (3.9% C, 2.6% Si, 0.42% Mn, 0.08% P, 0.02% S) melted in an IST-040 high-frequency in- duction furnace. The study was conducted with the use of an experimental mass spectrometry facility with ionic probe with a mass number resolution of at most 300 and a diameter of the pri- mary ion beam up to 2 mm. The structure of the iron was studied with the help of a MIRA TESCAN scanning electron microscope equipped with an Inca Energy 350 attachment for energy dispersive analysis. The dependences of the reactions of interaction between the yttrium dissolved in the iron and hydrogen and of the in- teraction of the pure reagents on the temperature of the Gibbs energies were determined by computation and experimentally. RESULTS AND DISCUSSION Secondary-ion mass spectrometer gives a mass spectrum of secondary ions in a range that depends on the possibilities of the mass spectrometer. The mass spectrum of secondary ions contains peaks corresponding to all the elements present in the specimen and to multicharged, fragmentary and cluster ions, the probability of formation of which is much lower. There also the peaks of chemical compounds formed by ele- ments and by gas ions of the retained atmosphere. The most valuable information contained in a mass spec- trum is the proportion of the intensities of the detected peaks. However, it is impossible to determine the chemical compo- sition directly from the mass spectrum, because the intensity of the secondary ions depends not only on the concentration of the element, but also on many other hard-to-allow-for factors. In order to determine the chemical composition of a spe- cimen by the method of SIMS, we should use relative mea- Metal Science and Heat Treatment, Vol. 60, Nos. 7 – 8, November, 2018 (Russian Original Nos. 7 – 8, July – August, 2018) 478 0026-0673/18/0708-0478 © 2018 Springer Science+Business Media, LLC 1 Saratov National Research State University after N. G. Cherny- shevsky, Saratov, Russia (e-mail: sergey.venig@gmail.com). DOI 10.1007/s11041-018-0304-4