Stephenson & Associates, Inc. Materials, Technology, and Management Stephenson & Associates, Inc. Tel : +1 (714) 970-18764704 Avenida De Las Flores Fax : +1 (714) 464-5435 Yorba Linda, CA 92886 Email:literature@stephenson-associates-inc.com United States of America Tap Density Quality Procedure - ISO 3953Scope 1.1The international standard specifies a method for the determination of tap density that has beentappedinacontainerunderspecificconditions.ThisstandardisbasedontheISO designation 3953 (1993) 1.2 This standard may involve hazardous materials, operation, and equipment.Thisstandard does not address all of the safety concerns associated with its use.It is the responsibility of whoever uses this standard to consult and establish appropriate safetyand health practices and determine the applicability of regulatory limitations prior to use. Principle 2.1A specified amount of powder in a container is tapped by means of a tapping apparatus until nofurtherdecreaseinthevolumeofthepowdertakesplace.Themassofthepowder divided by its volume after the test gives its tap density. Symbols Table 1 Symbol Description UnitstTap densityg/cm3m Mass of powder gV Volume of the tapped powder cm3 Apparatus 4.1Balance, of appropriate capacity and accuracy to satisfy the requirements shown in Table 2. 4.2Graduated glass cylinder, calibrated to contain 100 cm3, the height of the graduated portion beingapproximately175mm.Thegraduationsshallbeat1cm3intervals,thusallowinga measuring accuracy of 0.5 cm3. A25cm3cylindershallbeusedforpowdersofapparentdensityhigherthan4g/cm3,in particular for refractory metal powders, but may also be used for powder of lowerapparent density. 4.350 mesh sieve, used to prepare the sample powder. 4.4Glassine paper, used to collect the sieved powder and transfer into graduated cylinder. 4.5Tapping Apparatus, which permits the tapping of the graduated cylinder against a firm base.Thetappingshallbesuchthatadensificationofthepowdercantakeplacewithoutany loosening of its surface layers.The stroke shall be 3 mm and the tapping frequency shall be between100and300tapsperminute.Examplesofthetappingapparatusareshownin Figure 1. Stephenson & Associates, Inc. Materials, Technology, and Management Stephenson & Associates, Inc. Tel : +1 (714) 970-18764704 Avenida De Las Flores Fax : +1 (714) 464-5435 Yorba Linda, CA 92886 Email:literature@stephenson-associates-inc.com United States of America Tap Density Quality Procedure - ISO 3953 Figure1.ExamplesofTapDensityTesters.A)StampvolumeterJELSTAV2003,B) Quantachrome Autotap, C) Grover ETD 1020, and D) SOTAX TD2. Sampling 5.1For the quantities of powder required for each test, see Table 2. Table 2 Apparent Cylinder Mass ofDensity Capacity Test Portion(g/cm3) (cm3) (g)1 100 100 0.57 25 100 0.5>2 to 7 25 25 0.050.8 to 2 25 20 0.125 g of sample powder through 50 mesh on to a glassine paper. ABCD Stephenson & Associates, Inc. Materials, Technology, and Management Stephenson & Associates, Inc. Tel : +1 (714) 970-18764704 Avenida De Las Flores Fax : +1 (714) 464-5435 Yorba Linda, CA 92886 Email:literature@stephenson-associates-inc.com United States of America Tap Density Quality Procedure - ISO 39536.3Weightothenearest0.05gthemassofthetestportionasindicatedinTable2usingthe analytical balance from Step 6.2. 6.4Pour the test portion into the graduated cylinder.Take care that a level surface of the powder isformed.Placethecylinderinthetappingapparatus.Tapthecylinderuntilnofurther decrease in the volume of the powder takes place. 6.5Ifthetappedsurfaceislevel,readthevolumedirectly.Ifthetappedsurfaceisnotlevel, determine the highest and lowest reading of the tapped surface.Read the final volume to the nearest 0.5 cm3 when using a 100 cm3 cylinder and to the nearest 0.2 cm3 when using a 25 cm3 cylinder. Expression of Results 7.1The tap density is given by the formula Vmt = where the terms are defined in Table 1. 7.2Report the result to the nearest 0.1 g/cm3.

Test Report 8.1The test report shall include the following information: a)a reference to this standard b)all details necessary for identification of the test sample c)the drying procedure (if used) d)the cylinder capacity, mass of the test portion, and method used e)the results f)all operations not specified in this standard g)details of any occurrence which may have affected the result NOTES 1.In practice, the minimum number of taps, N, such that no further change in volume takes place would be determined apriori.For all further tests on the same type of powder, the cylinder would be subjected to 2N taps, except where general experience and acceptance had established a specific number of taps as being satisfactory.For fine refractory metal powders, 3,000 taps has been found to be satisfactory for all sizes. 2.In general, the mechanical and manual methods will give comparable results.However, for powders of very low apparent density, or for very fine powders, the results obtained by the two methods may be significantly different.