STP618

    Determination of Trace Elements of Metallurgical Interest in Complex Alloy Matrices by Nonflame Atomic Absorption Spectroscopy

    Published: Jan 1977


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    Abstract

    Atomic absorption with the high-temperature graphite tube furnace as an atomization source has proven to be particularly versatile in the determination of trace elements in complex alloys such as those used in gas turbine engines. Elements which are harmful to mechanical properties at levels of from 0.1 to 10 ppm include lead, bismuth, thallium, selenium, and tellurium. Indium, antimony, tin, and gallium are harmful at concentrations between 10 and 50 ppm. Accurate and reliable nonflame methods have been established in our laboratory for the determination of all these elements in complex alloys. Proper optimization of several variables is important in obtaining good results. The choice of dissolution medium is important to prevent volatilization losses of trace elements during sample preparation and during the thermal cycle before sample atomization. Selection of proper heating parameters before atomization can be instrumental in reducing background absorption and in realization of best sensitivity. Good alignment of analyte hollow cathode beam with background correction beam is critical for realization of maximum sensitivities. A comparison of the direct nonflame atomic absorption technique with other methods for trace element analysis such as emission spectroscopy, mass spectrometry, and flame atomic absorption after preconcentration shows advantages of speed, accuracy, and versatility. Recent work in our laboratory has suggested that some trace element determinations may be possible using direct atomization of the element from alloy chips. Significant advantages in sensitivity, reduction of background absorption, and speed may result from atomization from metal chips.

    Keywords:

    atomic absorption, atomizing, alloys, trace elements, analysis


    Author Information:

    Marks, JY
    Senior research associate and assistant materials project engineer, Analytical Chemistry Section, Materials Engineering and Research Laboratory, Pratt & Whitney Aircraft, East Hartford, Conn.

    Welcher, GG
    Senior research associate and assistant materials project engineer, Analytical Chemistry Section, Materials Engineering and Research Laboratory, Pratt & Whitney Aircraft, East Hartford, Conn.


    Paper ID: STP26967S

    Committee/Subcommittee: E01.08

    DOI: 10.1520/STP26967S


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