PHYSICAL REVIEW A 84, 042509 (2011) Effect of pH treatment on K -shell x-ray intensity ratios and K -shell x-ray-production cross sections in ZnCo alloys N. Kup Aylikci, 1,* V. Aylikci, 1 A. Kahoul, 2,3 E. Tiras ¸o˘ glu, 1 ˙ I. H. Karahan, 4 and E. Cengiz 1 1 Department of Physics, Faculty of Sciences, Karadeniz Technical University, TR-61080 Trabzon, Turkey 2 Bordj-Bou-Arreridj University Center, Institute of Science and Technology, 34000, Algeria 3 Physics Department, Laboratory LESIMS, Ferhat Abbas University, Faculty of Science, 19000 Setif, Algeria 4 Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, TR-31040 Hatay, Turkey (Received 7 June 2011; published 18 October 2011) In this study, empirical and semiempirical K-shell fluorescence yields (ω K ) and Kβ/Kα intensity ratios from the available experimental data for elements with 23  Z  30 were calculated to compare them with elements in different alloys. The experimental data are fitted using the quantity [ω K / (1 − ω K )] 1/ 4 vs Z to deduce the empirical K-shell fluorescence yields and Kβ/Kα intensity ratios. The empirical and semiempirical K-shell fluorescence yield values were used to calculate the K x-ray-production cross-section values for pure Co and Zn elements. Also, σ Kα , σ Kβ production cross sections and Kβ/Kα intensity ratios of Co and Zn have been measured in pure metals and in different alloy compositions which have different pH values. The samples were excited by 59.5-keV γ rays from a 241 Am annular radioactive source. K x rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The effect of pH values on alloy compositions and the effect of alloying on the fluorescence parameters of Co and Zn were investigated. The x-ray fluorescence parameters of Co and Zn in the alloying system indicate significant differences with respect to the pure metals. These differences are attributed to the reorganization of valence shell electrons and/or charge transfer phenomena. DOI: 10.1103/PhysRevA.84.042509 PACS number(s): 32.30.Rj I. INTRODUCTION Zinc and zinc alloys are widely used in the automobile industry to electroplate steel to provide corrosion resistance. The corrosion resistance of a pure zinc coating on steel is not satisfactory under severe atmospheric conditions. When elemental zinc is alloyed with iron-group metals, zinc shows better corrosion resistance than the pure metal. Thus, the investigation of properties of ZnCo alloys is interesting since these alloys exhibit a significantly higher corrosion resistance than pure zinc [1,2]. Depending on the preparation conditions, i.e., electrolyte composition, temperature, current density, and pH of the solution, different properties can be obtained. This fact makes ZnCo alloys important in exploring the effect of pH on the structure of these alloys. The effect of pH also changes the concentration of elements in the samples and distribution of outer shell electrons. The observed changes in the distribution of outer shell electrons lead to alteration of the binding energy of these electrons. The study of x-ray fluorescence parameters provides useful information on the electronic structure of 3d transition metals in their alloys and compounds. The information about the distribution of outer shell electrons is obtained by the different value of these parameters of elements in different alloy compositions since the x-ray fluorescence parameters depend on the physical and chemical environments of the elements in the samples. This dependence can be explained by the changes of the 3d electron population of the transition metal. The changes of the 3d electron population are explained by two mechanisms. The first mechanism is the transfer of valence shell electrons from one element to the other and the second is the reorganization of * nuraykup@ktu.edu.tr valence shell electrons in each atom. In alloys the 3d electron transfer or delocalization is responsible for the change in these parameters. Therefore it can be said that the x-ray fluorescence parameters are a sensitive tool to investigate the structure of transition metals in alloys. The alloying effect is explained by the change of the 3d electron population of both elements in different alloy compositions. The change of the 3d electron population in the atom will modify the 3p orbitals more than the 2p orbitals which results in a change of the Kβ -to-Kα ratio. In the 3d transition metal series, the valence state is 3d4s shells and the valence state electrons or outer shell electrons are more affected by the alloying or alien element effect than inner shell electrons. In the literature, many studies related to the effect of alloying are available and these studies are important for understanding the valence electronic structure of metals. The valence electronic structures of Fe and Ni in Fe x Ni 1−x alloys and of Ti, Cr, Fe, and Co in some alloys were investigated by using the changes in the relative Kβ/Kα x-ray intensity ratio. The changes in the 3d electron population of elements in various alloys were explained by assuming rearrangement of electrons between 3d and (4s,4p) states [3–5]. Influence of the alloying effect on the K x-ray intensity ratio was investigated for V and Ni elements in V x Ni 1−x alloys. The changes in the valence electronic structure and 3d electron population of elements in those alloys were clarified by rearrangement and charge transfer models [6]. In addition to these studies, the alloying effect on the K-shell fluorescence yield was investigated for Ni in Ni-Si alloys [7] and for Cr, Ni, and Al elements in Cr x Ni 1−x and Cr x Al 1−x alloys [8]. Electronic structures of Au-Al thin-film alloys by high-energy x-ray photoelectron spectroscopy (XPS) and x-ray absorption near-edge structure (XANES) were studied. It is concluded that the direction of charge transfer was in agreement with 042509-1 1050-2947/2011/84(4)/042509(10) ©2011 American Physical Society