1、 Reference number ISO 24369:2005(E) ISO 2005INTERNATIONAL STANDARD ISO 24369 First edition 2005-10-01 Fine ceramics (advanced ceramics, advanced technical ceramics) Determination of content of coarse particles in ceramic powders by wet sieving method Cramiques techniques Dtermination du contenu en p
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7、ights reservedISO 24369:2005(E) ISO 2005 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Terms and definitions. 1 3 Apparatus 1 4 Sampling 2 5 Measuring procedures . 2 6 Calculation. 4 7 Report 5 ISO 24369:2005(E) iv ISO 2005 All rights reservedForeword ISO (the International Organiz
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12、rights. ISO 24369 was prepared by Technical Committee ISO/TC 206, Fine ceramics. INTERNATIONAL STANDARD ISO 24369:2005(E) ISO 2005 All rights reserved 1 Fine ceramics (advanced ceramics, advanced technical ceramics) Determination of content of coarse particles in ceramic powders by wet sieving metho
13、d 1 Scope This International Standard specifies the procedure to determine the content of coarse particles in a fine ceramic powder and/or in a fine ceramic suspension using an aqueous-based wet sieving method. The procedure is applicable to fine ceramic powders of both micrometre and submicrometre
14、size ranges. It is valid when there are greater than 10 mg/kg coarse particles in the powders. NOTE It is recommended that new operators of this test method become familiar with the procedure, using a reference powder on slurry with a known quantity of coarse particles present. 2 Terms and definitio
15、ns For the purposes of this document, the following terms and definitions apply. 2.1 coarse particles particles and/or aggregates that cannot pass a 500 mesh sieve with 25 m mesh size 2.2 percentage of coarse particles ratio of the mass of the coarse particles (remaining on the sieve) to the total m
16、ass of the powder sample analysed 2.3 suspension ceramic powder suspended in an aqueous medium 2.4 solid content amount of powder in a suspension, ratio of the mass of powder to the total mass of the suspension (powder + medium) 3 Apparatus 3.1 Sieve: 500 mesh (the aperture size is 25 m). A stainles
17、s-steel rimmed sieve is recommended. 3.2 Analytical balance, having a readability of at least 0,1 mg. 3.3 Bottle: a glass weighing bottle with known mass m a . 3.4 Glass beaker, with a known mass m eand a volume of at least 250 cm 3 . ISO 24369:2005(E) 2 ISO 2005 All rights reserved3.5 Pipette, 10 m
18、l. 3.6 Oven: capable of controlling a temperature of 105 C 5 C. 3.7 Stirring apparatus: magnetic stirrer and polytetrafluoroethylene (PTFE)-coated stir bar. 3.8 Ultrasonic bath. 3.9 Desiccator or vacuum chamber. 4 Sampling A sample of suspension is required. The amount of powder needed for the measu
19、rement is about 30 g 2 g. The solid content of the suspension may vary but must be known (in weight percent). 5 Measuring procedures In the following measuring procedures, humidity is easily adsorbed either from hands or from the air. Therefore, be careful not to touch the sieve and glass weighing b
20、ottle with bare hands; use clean tongs or powder-free latex gloves. 5.1 Washing and drying of sieve Submerse the entire sieve in a clean ultrasonic bath filled with distilled water, and ultrasonicate for 10 min. It is recommended that the sieve is upright in the ultrasonic bath to avoid the re-adhes
21、ion of undesirable particles. Remove the sieve and drain bath, refill with fresh distilled water, and repeat the treatment. After washing, place the sieve in an oven, and dry it at 105 C for 2 h. After drying, cool the sieve down to room temperature in either a desiccator or a vacuum chamber and let
22、 it equilibrate there at room temperature for at least 10 min. 5.2 Weighing of sieve After equilibration, determine the mass m sof the sieve, to within 0,1 mg, with a balance directly from the desiccator or vacuum chamber. Calculate the sieve mass m s*by averaging the values of three measurements, e
23、ach obtained after equilibration of the balance. 5.3 Determination of solid content The following is the procedure for the determination of solid content. a) Preliminary treatment of the suspension for sampling: mildly agitate the suspension by shaking or magnetic stirring long enough, so that any s
24、edimentation is compensated for and homogeneity is attained. For a well-dispersed suspension, this might be in the range of 2 to 3 min; for a suspension that is partly deposited, the required time may be up to several hours. Do not use ultrasonic treatment, as this could influence the coarse particl
25、e fraction by rupturing existing agglomerates. b) Take an amount of about 1 to 2 ml of suspension, by means of a pipette, and place it in a glass weighing bottle of known mass m a(to within 0,1 mg). Determine the mass of suspension with a glass weighing bottle m bto within 0,1 mg. Calculate the susp
26、ension plus bottle mass m b*by averaging the values of three measurements, each obtained after equilibration of the balance. c) Place the weighing bottle with the suspension sample in an oven to dry at 105 C for at least 2 h. After drying, transfer the weighing bottle with the dried suspension to ei
27、ther a desiccator or a vacuum chamber for cooling to room temperature, and let it equilibrate there at room temperature for at least 10 min. ISO 24369:2005(E) ISO 2005 All rights reserved 3 d) After equilibrating, determine the mass of the glass weighing bottle with the dried suspension m c , to wit
28、hin 0,1 mg, directly from the desiccator or vacuum chamber. Calculate the sample plus bottle mass m c*by averaging the values of three measurements, each obtained after equilibration of the balance. e) Calculation of the solid content SC as a ratio of masses of powder and suspension: m suspension= m
29、 b* m a , in grams (1) m powder= m c* m a , in grams (2) powder suspension SC m m = (3) 5.4 Sampling and determination of mass of suspended powder The following is the procedure for sampling and determination of mass of suspended powder. a) Preliminary treatment of the suspension for sampling: mildl
30、y agitate the suspension by shaking or magnetic stirring, for long enough so that any sedimentation is compensated for and homogeneity is attained. For a well-dispersed suspension, this might be in the range of 2 3 min; for a suspension that is partly deposited, the required time may be up to severa
31、l hours. Do not use ultrasonic treatment, as this could influence the coarse particle fraction by rupturing existing agglomerates. b) The absolute amount of powder needed is about 30 g. Therefore, the sample for measurement is obtained from the suspension with a now known SC by weighing. The amount
32、used depends on the solid content, so that the amount of powder is about 30 g 2 g. The required mass of suspension can be calculated by m suspension= powder SC m(4) EXAMPLE When SC in a suspension is 0.3, 100 g of a suspension is required. Also, 37,5 g of a suspension is required when SC is 0,8. c)
33、Place the required amount of suspension into a beaker of known mass m e(to within 0,1 mg). Determine the mass m fof beaker with suspension to within 0,1 mg. Determine the suspension plus beaker mass m f*by averaging the values of three measurements, each obtained after equilibration of the balance.
34、The mass m gof the suspension is given by Equation (5) m g= m f* m e(5) According to Equation (4), the mass m pof the powder in the suspension is given by m p= m g SC (6) 5.5 Separation of coarse particles The following is the procedure for separation of coarse particles. a) Wet the sieve and place
35、it in the shallow washing bath. Adjust the level of the mesh so that it is just below the water surface of the bath. In this way, the mesh of the sieve will be covered with water. ISO 24369:2005(E) 4 ISO 2005 All rights reservedb) Pour the sample suspension slowly, and little by little, into the sie
36、ve so that nothing of the suspension is lost. In case the sieve becomes clogged with material, dilute and disperse the clogged material by pouring distilled water into the sieve. Take care that the suspension is quantitatively transferred to the sieve by rinsing the beaker with distilled water at th
37、e end. NOTE 1 Coarse particles tend to sediment during slow pouring, and therefore concentrate in the last 5 10 % of the slurry. Coarse particles may adhere to a glass beaker. It is recommended to dry the beaker and inspect retained coarse particles. If these are found, they should be removed with w
38、ater and the resultant suspension should be wet-sieved. c) Rinse away any suspension that is attached to the sieve frame with distilled water, then pour a sufficient amount or volume of distilled water into the sieve. NOTE 2 About 10 L might be a sufficient volume. d) Take care that all particles ar
39、e on the mesh of the sieve and nothing is left on the sieve frame. e) If the slurry viscosity is excessively high, dilute the slurry with a proper liquid, for which the chemistry is the same as that of the supernatant of the slurry. Alternatively, take care that the mesh of the sieve be covered with
40、 water, with no air bubbles between the mesh and water surface, during sieving. 5.6 Drying and weighing of sieve with coarse particles Follow the same procedures as detailed in 5.1 and 5.2 to measure the mass m scp*of the sieve with coarse particles. 5.7 Washing the sieve Wash the sieve upside down
41、for 10 min in clean water in an ultrasonic bath. Remove the sieve and turn it over, so that the mesh is upright, and wash for an additional 10 min. Drain the bath and refill with fresh water. Repeat the washing treatment. Dry the sieve as in 5.1. 6 Calculation The percentage X of coarse particles in
42、 the powder, in milligrams per kilogram, can now be determined according to Equation (7). scp* s* 6 p 10 mm X m = (7) where m scp*is the mass, in grams, of sieve plus coarse particle (5.5); m s*is the sieve mass, in grams, before the experiments (5.1); m pis the determined mass, in grams, of powder.
43、 The values of m scp*and m s*are the average ones. ISO 24369:2005(E) ISO 2005 All rights reserved 5 7 Report For the report, fill in the attached data sheet. Data Sheet Table 1 Experimental parameters Laboratory or organization Analyst Date of analysis Powder Type Comments Dispersion Type Comments (
44、pretreatment, pH, etc.) Sieve Inside diameter (mm) Table 2 Determination of solid content, weighing results m ag m bg m cg m suspensiong m powderg Solid content 1 1 2 2 3 3 m b*m c*m b* m am c* m aSC Table 3 Weighing-test results Sieve mass g m eBefore experiments m sbAfter experiments m saMass of beaker with suspension m fSuspension mass m f* m ePowder mass m g SC Mass of coarse particles + sieve Content of coarse particles g g g g g mg/kg 1 1 1 1 2 2 2 2 3 3 3 3 m sb*m sa*m f*m gm pm scp*X ISO 24369:2005(E) ICS 81.060.30 Price based on 5 pages ISO 2005 All rights reserved
