1、Designation: E 1257 93 (Reapproved 2003)Standard Guide forEvaluating Grinding Materials Used for Surface Preparationin Spectrochemical Analysis1This standard is issued under the fixed designation E 1257; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers recommendations for the evaluationof various grinding materials us
3、ed to prepare the surfaces ofspecimens to be analyzed by optical emission or X-rayemission spectroscopy.1.2 This standard does not purport to address all of thesafety problems, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and
4、health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:E 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related Materials23. Terminology3.1 For definitions of terms used in this guide, refer toTerminol
5、ogy E 135.4. Significance and Use4.1 The grinding materials used for the preparation of thesurfaces of specimens prior to analysis by optical emission orX-ray emission spectroscopy can contaminate the surface andthus produce erroneous results. This guide provides examplesof the effects of these cont
6、aminations and recommendations forevaluating grinding materials to eliminate or reduce theseeffects in spectrochemical analysis.4.2 The examples given in this guide are not the onlycontaminations which can occur. Especially in X-ray spectrom-etry, all phases of the surface preparation should be exam
7、inedfor potential contamination effects.4.3 Analytical significance of the contaminations observeddepends on the needs of the analyst for the particular applica-tion at a given concentration level.5. Evaluation of Grinding Materials by Direct Analysis5.1 Table 1 shows an example of semiquantitative
8、spectro-graphic analysis of various grinding belts from differentproducers. An examination of these analyses identifies theelements most likely to contaminate the surface of the speci-men. The more critical the element and the lower its concen-tration in the specimen, the more important are low-leve
9、lconcentrations in the belts.5.1.1 For example, using the 80-grit zircon belt in thedetermination of 0.5 % chromium, the trace level of chromiumin the belt should cause no problem, but in the determination of0.02 % aluminum, that belt probably will cause a problem. Inthe determination of calcium at
10、ppm levels in steel, even lowlevels of calcium in the belts cause problems.5.2 Figs. 1-6 show energy dispersive X-ray analyses ofvarious belts and the same logic applied in 5.1 can be used withthese analyses. Major components in the belts will causegreater problems in the determination of these elem
11、ents.5.2.1 Direct analysis of the grinding material is particularlyuseful in such analyses as the determination of calcium in steel,where the analyte is generally too inhomogeneous to use themethods described in Section 6. This analysis requires avirtually calcium-free belt as in Fig. 2.6. Evaluatio
12、n of Grinding Materials by SpecimenExamination6.1 The effect of grinding materials depends on the analyti-cal method. In optical emission analysis, the preburn will, ingeneral, volatilize the grinding material left on or driven intothe surface (see 6.3). For X-ray emission analysis, the materialleft
13、 on the surface will be analyzed as being specimen material.6.2 Table 2 shows X-ray emission analyses of a steelspecimen after surfacing with various grinding materials. Bytabulating the results in this manner, it becomes obvious whatproblems are occurring from the various grinding materials.Where t
14、here is no change from material to material, beyond theprecision of the method of analysis and the homogeneity of thematerial, no contamination has occurred. But where the con-centration of a given element appears higher, there has beencontamination. Such is the case with the determination ofsilicon
15、 using the silicon carbide belt and the bonded diamondwheels; with the determination of zirconium using zircon belts;1This guide is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals, Ores and Related Materials and is the direct responsibility ofSubcommittee E01.20 on Fun
16、damental Practices and Measurement Traceability.Current edition approved June 10, 2003. Published July 2003. Originallyapproved in 1988. Last previous edition approved as E 125793(1998)e1.2Annual Book of ASTM Standards, Vol 03.05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, Wes
17、t Conshohocken, PA 19428-2959, United States.with the determination of aluminum using the alumina andzircon belts, the bonded diamond wheels, and the surfacegrinder; and with the determination of nickel using the metalbonded diamond wheel.6.2.1 This method requires the use of homogeneous mate-rials
18、to attain the required precision to detect low levels ofcontamination. Materials should be examined by replicatedeterminations using the same grinding material beforehand toassure that they are homogeneous. If inhomogeneity seems tobe excessive for one element, that may come from the grindingmateria
19、l, for example, silicon from silicon carbide, repeat theexamination using a different grinding material.6.2.2 Generally this method is convenient because it deter-mines the contamination which actually occurs in the type ofmaterial being analyzed and does not require analysis of thegrinding material
20、 itself. An exception is the calcium determi-nation mentioned in 5.2.1.6.3 In optical emission analysis, a finite time is required toclean the specimen surface (by volatilization). Intensity-timestudies show that preburn periods as long as 20 s can berequired to reach stable intensity ratios for ele
21、ments compris-ing the grinding matrix. Fig. 7 shows time studies for carbon ina specimen surfaced with silicon carbide, alumina, zircon, andTABLE 1 Semiquantitative (Spectrographic) Analysis of Grinding Belt AbrasivesConcentration,%80-Grit Silicon Carbide 80-Grit Alumina80-Grit ZirconNo. 1 No. 2 No.
22、 3 No. 1 No. 2 No. 310+ Si Si Si Al Al, Ca Al Al, Ca, Zr110 Ca Ca Ti Si, Na, Fe0.11 Ba, Mg Fe, Al, Na Mg, Si, Ca, Ti Fe, Si, Na Ca Ti, Zn0.050.5 B Fe, B Mg0.010.1 Mn, Na B, Mg Al Ba, B Zr Na Mg0.0050.05 V, Cu, Ti, Ni Mn, Ti V, Ca, Na, Ni Mn, Zr, Cu, Na B B, Fe, Si B, Mn, SrTrace0.01 Mo, Zr, Sr Ba, V
23、, Zr, Cu,Ni, SrBa, Mn, Mg, Pb, Cr,Zr, Cu, Ti, SrNi Ba, Mn, Cr, V,Cu, Ni, SrMn, Mo, Cu,Sr, MgBa, Pb, Cr, V,Mo, CuFIG. 1 EDX Analysis of Silicon Carbide Grinding Belt, 60-GritFIG. 2 EDX Analysis of Silicon Carbide Grinding Belt, 240-GritFIG. 3 EDX Analysis of Alumina Grinding Belt, 60-GritFIG. 4 EDX A
24、nalysis of Alumina Grinding Belt, 120-GritE 1257 93 (2003)2a lathe. Fig. 8 shows the time studies for aluminum. Under theconditions used for these tests, a total of 4800 dischargesoccurred in the 20-s period. Sources running at lower rates mayrequire longer preburn periods. Fig. 8 shows that, compar
25、ed toa specimen surfaced with lathe, the aluminum value found atthe end of the preburn period can be higher on the alumina andzircon ground specimens. Analytical significance will dependon the concentration level. Similar results can be shown forother elements, especially silicon and zirconium under
26、 theconditions used. Different source conditions may show differ-ent results.6.3.1 Although the preburn generally removes most of thegrinding material, in analyses where the highest accuracy isdesired, grinding materials containing the analyte elementshould be avoided.7. Keywords7.1 grinding materia
27、l; specimen preparation; spectrochemi-cal analysisFIG. 5 EDX Analysis of Zircon Grinding Belt, 60-GritFIG. 6 EDX Analysis of Zircon Grinding Belt, 120-GritE 1257 93 (2003)3TABLE 2 X-Ray Fluorescence Analysis of a Steel Specimen Using Various Grinding MediaApparent Concentration, %, UsingElement Si C
28、 Belt Alumina Belt Zircon BeltResin BondedDiamondMetal BondedDiamondDiamond Paste Surface GrinderMolybdenum 0.057 0.056 0.058 0.057 0.057 0.057 0.058Niobium 0.034 0.032 0.032 0.033 0.032 0.032 0.033Copper 0.315 0.310 0.320 0.316 0.317 0.316 0.317Nickel 0.297 0.296 0.292 0.295 0.322A0.296 0.295Cobalt
29、 0.014 0.011 0.010 0.011 0.010 0.011 0.012Manganese 1.39 1.40 1.39 1.40 1.39 1.40 1.40Chromium 0.197 0.193 0.197 0.196 0.195 0.196 0.195Vanadium 0.061 0.059 0.060 0.059 0.060 0.059 0.059Titanium 0.024 0.025 0.024 0.024 0.025 0.024 0.024Phosphorus 0.012 0.011 0.012 0.011 0.012 0.012 0.011Silicon 0.44
30、4A0.234 0.234 0.245A0.293A0.235 0.236Antimony 0.006 0.005 0.005 0.005 0.006 0.005 0.006Tin 0.023 0.022 0.023 0.023 0.022 0.023 0.022Aluminum 0.016 0.070A0.085A0.026A0.090A0.015 0.030AZirconium 0.050 0.051 0.066A0.051 0.050 0.051 0.050AElements that exhibit contamination from grinding media.FIG. 7 Ti
31、me Studies: CarbonOptical Emission Analysis of High-Purity IronE 1257 93 (2003)4ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the val
32、idity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your com
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34、 not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).FIG. 8 Time Studies: AluminumOptical Emission Analysis of High-Purity IronE 1257 93 (2003)5
