1、Designation: E 1257 93 (Reapproved 2008)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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers recommendations for the evaluationof various grinding materials use
3、d 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 h
4、ealth practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related Materials3. Terminology3.1 For definitions of terms used in this guide, refer toTerminolo
5、gy 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 conta
6、minations 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 exami
7、nedfor 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 s
8、pectro-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-level
9、concentrations 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 p
10、pm 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 eleme
11、nts.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. Evaluation
12、 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 what1This guide is under the jurisdiction of ASTM Committee E01 on Anal
14、yticalChemistry for Metals, Ores and Related Materials and is the direct responsibility ofSubcommittee E01.20 on Fundamental Practices.Current edition approved May 1, 2008. Published June 2008. Originallyapproved in 1988. Last previous edition approved in 2003 as E 1257 93 (2003).2For referenced AST
15、M standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoho
16、cken, PA 19428-2959, United States.problems are occurring from the various grinding materials.Where there 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 e
17、lement appears higher, there has beencontamination. Such is the case with the determination ofsilicon using the silicon carbide belt and the bonded diamondwheels; with the determination of zirconium using zircon belts;with the determination of aluminum using the alumina andzircon belts, the bonded d
18、iamond 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 to attain the required precision to detect low levels ofcontamination. Materials should be examined by replicatedeterminations
19、using the same grinding material beforehand toassure that they are homogeneous. If inhomogeneity seems tobe excessive for one element, that may come from the grindingmaterial, for example, silicon from silicon carbide, repeat theexamination using a different grinding material.6.2.2 Generally this me
20、thod is convenient because it deter-mines the contamination which actually occurs in the type ofmaterial being analyzed and does not require analysis of theTABLE 1 Semiquantitative (Spectrographic) Analysis of Grinding Belt AbrasivesConcentration,%80-Grit Silicon Carbide 80-Grit Alumina80-Grit Zirco
21、nNo. 1 No. 2 No. 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
22、Mo, Zr, Sr Ba, V, 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-
23、GritFIG. 4 EDX Analysis of Alumina Grinding Belt, 120-GritE 1257 93 (2008)2grinding material 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
24、that preburn periods as long as 20 s can berequired to reach stable intensity ratios for elements compris-ing the grinding matrix. Fig. 7 shows time studies for carbon ina specimen surfaced with silicon carbide, alumina, zircon, anda lathe. Fig. 8 shows the time studies for aluminum. Under thecondit
25、ions 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, compared toa specimen surfaced with lathe, the aluminum value found atthe end of the preburn period can be higher on the alumina andz
26、ircon ground specimens. Analytical significance will dependon the concentration level. Similar results can be shown forother elements, especially silicon and zirconium under theconditions used. Different source conditions may show differ-ent results.6.3.1 Although the preburn generally removes most
27、of thegrinding material, in analyses where the highest accuracy isdesired, grinding materials containing the analyte elementshould be avoided.7. Keywords7.1 grinding material; specimen preparation; spectrochemi-cal analysisFIG. 5 EDX Analysis of Zircon Grinding Belt, 60-GritFIG. 6 EDX Analysis of Zi
28、rcon Grinding Belt, 120-GritE 1257 93 (2008)3TABLE 2 X-Ray Fluorescence Analysis of a Steel Specimen Using Various Grinding MediaApparent Concentration, %, UsingElement Si C Belt Alumina Belt Zircon BeltResin BondedDiamondMetal BondedDiamondDiamond Paste Surface GrinderMolybdenum 0.057 0.056 0.058 0
29、.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 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.
30、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 0.444A0.234 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
31、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 Time Studies: CarbonOptical Emission Analysis of High-Purity IronE 1257 93 (2008)4ASTM International takes no position respecting
32、 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 validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standar
33、d 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 comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International
34、 Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.Thi
35、s 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 (2008)5
