Measurements of a Cr/Fe nickel alloy using fixed angle SQX

Rigaku's ZSX Primus II WDXRF spectrometer contains a standardless, semi-quantitative analysis program, referred to as SQX. With this program, a qualitative analysis is run, and the detected elements are then quantified by the fundamental parameter (FP) method without the use of reference standard samples. In the quantifying process, a sensitivity library is used which has the FP sensitivities for every element and which has been calibrated using pure metals and reagents.

SQX has a 'Fixed Angle' measurement function. Using this function, the X-ray intensity is collected at a fixed 2θ angle for a user-specified time, usually much longer than the time for a step in scanning; therefore, precision is improved and superior results can be obtained for trace element analysis. In this analysis, fixed angle measurements using counting times of 20 seconds for each of peak and background positions were carried out in SQX on the alloy (Figure 1). Some elements were detected by this fixed angle measurement method which were not evident in the spectral charts. The identified elements were then quantified (Table 1) showing good correlation to the certified concentrations of this material.

X-ray intensity is collected

Figure 1

The sample was polished with a belt grinder using #80 aluminum-zirconia belt to remove surface contaminants in order to improve analysis accuracy.

  Cr Fe Al Co Cu Mg Mn Mo Nb Ni Si Ti V P S
201A (Inco690) 29.9 9.09 0.37 0.009 0.008 0.006 0.19 0.018 0.009 59.9 0.15 0.30 0.011 0.005 0.0004
SQX 31.0 9.10 0.39 0.010 0.010 ND 0.19 0.015 0.007 59.0 0.13 0.30 0.013 0.0031 0.0005

Table 1: Cr/Fe nickel alloy