1、Designation: C925 09 (Reapproved 2014)Standard Guide forPrecision Electroformed Wet Sieve Analysis of NonplasticCeramic Powders1This standard is issued under the fixed designation C925; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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. Scope*1.1 This guide covers the determination of the particle sizedistribution of pulverized alumina and quartz
3、for particle sizesfrom 45 to 5 m by wet sieving.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.2.1 The only exception is in the Section 5, Apparatus, 5.1where there is no relevant SI equivalent.1.3 This standard does not
4、purport to address the safetyconcerns associated with its use. It is the responsibility of theuser of this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:2E161 Specificatio
5、n for Precision Electroformed Sieves3. Summary of Guide3.1 A separate dispersed suspension of the powder is wetsieved through each sieve, using vacuum and vibration. Thesieve and sample are dried and weighed.4. Significance and Use4.1 Both suppliers and users of pulverized ceramic powderswill find t
6、his test method useful to determine particle sizedistributions for materials specifications, manufacturingcontrol, development, and research.4.2 The test method is simple, although tedious, usesinexpensive equipment, and will provide a continuous curvewith data obtained with standardized woven sieve
7、s.5. Apparatus5.1 Precision Electroformed Sieves , 3-in., mounted in brassframes, having nominal apertures of 45, 30, 20, 10, and 5 mand a support grid having 5.7 lines per centimetre. Intermediatesizes may also be used.5.2 Sieving Device (Fig. 1):5.2.1 Filtering Flask (suction flask), 1-L, with sid
8、e arm,5.2.2 Bchner Funnel (for example, Coors No. 2),5.2.3 O-Ring, 7.5-cm, rubber,5.2.4 Graduate, 1-L,5.2.5 Rubber Stoppers, one-hole to fit the flask and thefunnel, two-hole to fit the graduate,5.2.6 Quantity of glass tubing and rubber tubing,5.2.7 Metal Rod, 15 to 20-cm, about 5 mm in diameter, an
9、d,5.2.8 Vacuum Source.5.3 Ultrasonic Cleaner, required to clean all sieves below20 m. It should be low-powered (for example, 100 W).5.4 Analytical Balance, capable of weighing up to 100 g andhaving at least three significant digits after the decimal.5.5 Drying Oven, capable of maintaining 110 6 5C.5
10、.6 Desiccator, containing magnesium perchlorate or othersuitable desiccant.6. Reagents and Materials6.1 Water, visually clear and particle free, not necessarilydistilled, at room temperature or slightly above.6.2 Sieving Solution, a dispersing media consisting of 0.1weight % solution of sodium hexam
11、etaphosphate or sodiumpyrophosphate in water.6.3 Drying Agents, acetone or methyl alcohol, commercialgrade.7. Sampling7.1 Since the amount of sample used in the determination isquite small, great care must be taken to avoid segregation.Gross samples must be cut down very carefully using splitters,ri
12、fflers, or simple cone and quartering techniques.Adjusting theportion to an exact weight must be avoided. That is, arepresentative portion must be extracted from the analyticalsample and all of it weighed and used.1This guide is under the jurisdiction of ASTM Committee C21 on CeramicWhitewares and R
13、elated Productsand is the direct responsibility of SubcommitteeC21.04 on Raw Materials.Current edition approved Dec. 1, 2014. Published December 2014. Originallyapproved in 1979. Last previous edition approved in 2009 as C925 09. DOI:10.1520/C0925-09R14.2For referenced ASTM standards, visit the ASTM
14、 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Har
15、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States18. Preparation of Apparatus8.1 Cleaning of SievesUse sufficient sieving solution tocover the sieve when suspended near the bottom of theultrasonic tank. (Some organic liquids are better but create adefinite explosion hazard.) Tu
16、rn on the generator for about 30s. Fine sieves may need multiple treatments. (Exposure toultrasonic energy for periods exceeding 30 s at one time maydamage the sieves.) After each cleaning carefully examine thesieve against a light, using a magnifying glass, for blockagesand breaks. (Breaks can be r
17、epaired with epoxy resin.) Sievesof 20 m and finer should be cleaned after each analysis. Rinsein clear water and dry at 110C.8.2 Collector and Vacuum ControlAssemble apparatus asshown in Fig. 1.9. Calibration and Standardization9.1 Calibration of SievesThis must be done for highlyaccurate analyses
18、or to verify the apertures that may not bewithin the quoted 2-m tolerance. The calibration procedure isgiven in Appendix X1 of Specification E161.10. Procedure10.1 Wash the sieves with the sieving solution, rinse withwater and then with the drying agent, dry at 110C for 15 min,cool in the desiccator
19、, and weigh to at least the nearest 1 mg.10.2 Sample Size is somewhat dependent upon density, butthe following schedule is satisfactory for alumina and quartz:Nominal SieveApertures, mSample Weight(approximate), g45, 30, 20 1.015, 10 0.45 0.1510.3 Weigh the required amount of sample into a 100-mLbea
20、ker, fill half with sieving solution (containing the dispersingagent), and disperse by placing beaker in ultrasonic bath for 1min. Microscopical examination of the particles after disper-sion may be helpful in determining if the dispersion iscomplete.10.4 Wash the dispersed sample onto the sieve usi
21、ng a washbottle containing the sieving solution, turn on vacuum (amaximum of 15 in. of water), and agitate. Continuously addsieving solution, at a rate sufficient to maintain a small amountin the sieve, until about 1 Lhas passed. Below 6 m the amountof liquid required is less due to the time for sie
22、ving. Agitate bysharp tapping on the sieve frame with the metal rod. For sievesabove 30 m the liquid runs quickly enough without vacuum sothat the air-bleed valve can be opened. The bleed-line shouldbe pinched occasionally, however, to draw the larger particlesthrough, but care must be taken to avoi
23、d damage to the sieve.For apertures of 10 m or less, when the sieving appearscomplete (that is, the filtrate is clear) or the rate of throughputbecomes very slow, draw the sieve down to near dryness withthe vacuum. Remove the sieve from the sieving device andpartially immerse it in the sieving solut
24、ion in the ultrasonictank for about 1 min. The particles that have blocked theapertures will be forced back into the sieve. Regular sieving isthen continued. This procedure must be repeated until the washsolution in the ultrasonic tank remains clear (not visuallycloudy) after washing. This may be as
25、 many as 4 to 5 times forthe 5-m sieve to assure that the sieving is complete.10.5 Rinse with water to remove any sieving solution andthen rinse with drying agent, dry for 15 min at 110C, cool inthe desiccator, and weigh sieve and sample.10.6 Triplicate replications are advised to assure repeatabil-
26、ity.11. Calculation and Report11.1 Report the “weight percent greater than aperture” foreach replicate and for each sieve along with the calibrated sieveopenings. Calculate as follows:W 5B 2 CD3100 (1)where:W = weight percent greater than aperture,B = weight of sieve with sample, g,C = weight of emp
27、ty sieve, g, andD = original sample weight, g.12. Keywords12.1 ceramic powders; particle size distribution; precisionelectroformed sieves; wet-sievesFIG. 1 Wet Sieving ApparatusC925 09 (2014)2SUMMARY OF CHANGESCommittee C21 has identified the location of selected changes to this standard since the l
28、ast issue(C92579(2000) that may impact the use of this standard.(1) The standard was changed form a Test Method to a Guidewith an appropriate change in title.(2) 1.1 and Section 3 were changed to reflect this change intype of standard.(3) 1.2 and 1.2.1, concerning use of units were added, withrenumb
29、ering of subsequent sections of the Scope.(4) 10.5 was edited to remove the requirement to use distilledwater since distilled water is specifically no required accordingto 6.1.(5) Section 12 on Precision and Bias was deleted since 1)precision and bias have not been determined for the testmethod desc
30、ribed in this guide and a Precision and Bias sectionis not required in a guide.ASTM 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 vali
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34、opies) 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 09 (2014)3
