Influence of binders on infrared laser ablation of powdered tungsten carbide pressed pellets in comparison with sintered tungsten carbide hardmetals studied by inductively coupled plasma atomic emission spectrometry Markéta Holá, Vítězslav Otruba, Viktor Kanický ⁎ Research Centre for Environmental Chemistry and Ecotoxicology and Laboratory of Atomic Spectrochemistry, Faculty of Science, Masaryk University in Brno, Kotlářská 2, CZ 611 37 Brno, Czech Republic Received 5 January 2006; accepted 10 March 2006 Available online 27 April 2006 Abstract Laser ablation (LA) was studied as a sample introduction technique for the analysis of powdered and sintered tungsten carbides (WC/Co) by inductively coupled plasma optical emission spectrometry (ICP–OES). The possibility to work with powdered and compact materials with close chemical composition provided the opportunity to compare LA sampling of similar substances in different forms that require different preparation procedures. Powdered WC/Co precursors of sintered hardmetals were prepared for the ablation as pressed pellets with and without powdered silver as a binder, while sintered hardmetal blocks were embedded into a resin to obtain discs, which were then smoothed and polished. A Q-switched Nd: YAG laser operated at its fundamental wavelength of 1064 nm with a pulse frequency of 10 Hz and maximum pulse energy of 220 mJ was used. A single lens was used for the laser beam focusing. An ablation cell (14 cm 3 ) mounted on a PC-controlled XY-translator was connected to an ICP spectrometer Jobin Yvon 170 Ultrace (laterally viewed ICP, mono- and polychromator) using a 1.5-m tubing (4 mm i.d.). Ablation was performed in a circular motion (2 mm diameter). Close attention was paid to the study of the crater parametres depending on hardness, cohesion and Ag binder presence in WC/Co samples. The influence of the Co content on the depth and structure of the ablation craters of the binderless pellets was also studied. Linear calibration plots of Nb, Ta and Ti were obtained for cemented WC/Co samples, binderless and binder-containing pellets. Relative widths of uncertainty intervals about the centroids vary between ± 3% and ± 7%, and exceptionally reach a value above 10%. The lowest determinable quantities (LDQ) of Nb, Ta and Ti calculated from the calibration lines were less than 0.5% (m/m). To evaluate the possibility of quantitative elemental analysis by LA–ICP–OES, two real sintered WC/Co samples and two real samples of powdered WC/Co materials were analysed. The results of LA–ICP–OES real sample analysis correlated well with the results obtained by X-ray fluorescence (sintered samples) and pneumatic nebulization inductively coupled plasma optimal emmission spectrometry (powdered samples) with a bias not exceeding 6.5%. © 2006 Elsevier B.V. All rights reserved. Keywords: Laser ablation; Inductively coupled plasma; Atomic emission spectrometry; Tungsten carbide; Powdered sample 1. Introduction Sintered carbide manufacturing requires a detailed knowl- edge of the elemental composition. This involves the analysis of the powdered precursors prior to the sintering process or, in the case of hardmetal recycling, the analysis of cemented compact products. In both cases, any liquid-based analytical methods require time-consuming decomposition procedures, the use of which is frequently associated with the risk of incomplete sample dissolution or loss of some of the elements. The decomposition is usually performed by means of a mixture of acids [1] or by using a solution of 5% aqua regia in 30% hydrogen peroxide [2]. The problems of solution preparation for materials which are difficult to decompose, such as tungsten carbides, can be circumvented by using direct solid analysis techniques where the sample treatment is considerably reduced. X-ray fluores- cence (XRF) spectrometry is frequently employed as a routine technique for this purpose [3]. Atomic absorption spectrometry Spectrochimica Acta Part B 61 (2006) 515 – 524 www.elsevier.com/locate/sab ⁎ Corresponding author. E-mail address: viktork@chemi.muni.cz (V. Kanický). 0584-8547/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.sab.2006.03.007