ASTM E1251-17 pdf free download.Standard Test Method for Analysis of Aluminum and Aluminum Alloys by Spark Atomic Emission Spectrometry.
6. Recommended Analytical Lines and Potential
Interferences
6. 1 Table I lists the analytical lines commonly used for aluminum analysis. Other lines may be used if they give comparable results. Also listed are recommended mass fraction ranges, background equivalent mass fractions, detection limits, useful linear ranges. and potential interferences. The values given in this table arc typical; actual values obtained are dependent on instrument design.
Nom 3—The background equivalent mass fraction and detection limits listed in Table I have been attained with a spectrometer that has a reciprocal dispersion of 54 nm/mm and a working resolution of 3.5 nm, using an entrance slit width of 25 im and exit slit widths of 50 pm.
7. Apparatus
7.1.1 Sampling Molds, for aluminum and the techniques of pouring a sample disk are described in Practices E716. Chill cast samples, poured and cast as described within Practices E716, shall be the recommended form in this test method.
7.1.2 Lathe, capable of machining a smooth, flat surface on the reference materials and samples. A variable speed cutter, a cemented carbide or polycrystalline diamond tool hit, and an automatic cross feed are highly recommended. Proper depth of cut and desired surface finish are described in Practices E7l6.
7. 1 .3 Milling Machine, a milling machine can he used as an alternative to a lathe.
7. 1 .4 It is strongly recommended that the same preparation machinery used to prepare the standards is also used to prepare the samples. Differences in surface characteristics may influence the analysis.
7.2 Excitation Source—In today’s instrumentation, the excitation source is computer controlled and is normally programmed to produce: (1) a high-energy pre-spark (of some preset duration), (2) a spark-type discharge (of some preset duration), (3) an arc-type discharge (of some preset duration), and (4) a spark-type discharge, during which, time-resolved measurements are made for improved detection limits (this may be optional on some instruments).
7.2.1 Typical parameters and times are given in Table 2. It should he emphasized that the information presented is given as an example only and parameters may vary with respect to instrument model and manufacturer. For details on describing and specifying an excitation source, please refer to Practice El72.
7.3 Excitation Chamber shall be designed with an upper plate that is smooth and flat so that it will mate (seal) perfectly with the prepared surface of the sample specimen. The seal that is formed between the two will exclude atmospheric oxygen from entering the discharge chamber. The excitation chamber will contain a mounting clamp to hold the counter electrode. The excitation stand assembly will also have some type of clamp or device designed to hold the sample firmly against the top plate.ASTM E1251 pdf download.