The determination of nitrogen in Cr-N system by RBS and the weight gain technique

Abstract

Precise quantitative compositional analysis of hard coatings based on transition metal nitrides and other compounds by means of standard analytical techniques (AES, XPS, EDX, RBS) is possible only using a standard reference material (SRM). However, such standards are still in the course of development. In this paper we show that RBS analysis and the weight gain (WG) technique can be used for the evaluation of atomic concentrations of coating constituents without using an SRM. RBS methods based on the use of two detectors and a sample prepared in the form of a multilayer structure were proposed and tested. Additionally, weight gain measurements were used as a second method to determine nitrogen content in single Cr-N layers. The N/Cr atomic ratio of the as-deposited sample was evaluated from the weight change induced after complete oxidation of the as-deposited films, assuming reactions in which Cr 2O 3 oxide is formed. The results of the two analytical techniques were in very good agreement. The AES depth profile of the same multilayer structure was also measured. All samples were prepared by reactive sputter deposition in a Sputron apparatus at 200 °C.