ISO 15901-1 pdf download – Evaluation of pore size distribution andporosimetry of solid materials by mercury porosimetry and gas adsorption— Part 1: Mercury porosimetry.
6 Apparatus and material
WARNING — it is important that proper precautions for the protection of laboratory personnel are taken when mercury Is used, Attention Is drawn to the relevant regulations and guidance documents which appertain for the protection of personnel In each of the member countries.
6.1 Sample holder! having a uniform bore capilary lube through which the sample can be evacuated and through which mercury can enter.
The capillary tube is attached to a wider bore tube in wtich the test sample is located. If precise measurements are required the internal volume of the capillary tube should be between 20% and 90 % of the expected pore and void volume of the sample, Since different materials exhib4 a wide range of open porosities a number of sample holders with different diameter capillary tubes and sample volumes may be required. A special design of sample holder is often used with powdered samples to avoid loss of powder during evacuation.
6.2 Poroslmeter. capable of carrying out the test as two sequential measurements, a low-pressure test up to at least 0,2 MPa (30 psia) and a high-pressure test up to the maximum operating pressure of the porosimeter [circa 400 MPa (60 000 psiafl.
The porosimeter may have several ports for high- and low-pressure operations, or the low-pressure test may be carried out on a separate unit
Pnor to any porosimetry measurement it is necessary to evacuate the sample using a vacuum pump. equipped with mercury retainer, to a residual pressure of 7 Pa or less and then to fill the sample holder with mercury to a given low pressure. A means of generating pressure Is necessary to cause intrusion of mercury.
A means of detecting the change In the volume of mercury intruded to a resolution of 1 mm3 or less is desirable. This is usualy done by measuring the change in capacitance between the mercury column in the capillary tube and a metal sleeve around the outside of the sample holder.
6.3 Mercury. of analytical quality, with a purity of at least ratio of 99,4 mass %.
7 Procedures for calibration and performance
7.1 General
Sample preparation and the filing of the sample holder with mercury require vacuum, the level of which is usually recorded using a transducer, For the porosity evaluation, two signals are required to be measured in a porosimeter the applied pressure and the corresponding volume change of mercury as it fills the pores in the sample. The volume of mercury displaced from a precision glass capillary tube is most commonly determined as a function of electncal capacity change.
7.2 Pressure signal calibration
Pressure is usually measured with electronic pressiwe transducers which will have been factory calibrated
The accuracy of the pressure measurement should be within t 1 % of the full scale transducer reading or
±2 % of the actual reading, whichever is the lower. ft Is recommended that venfication of calibration, traceable
to an accredited organisation, be regularly performed
7.3 Volume signal calibration
The accuracy of the volume measurement should be within ± I % of the total volume to be measured. It is recommended that verification of calration, traceable to an accredited organisation, be reguLarly performed.
8 Procedures
8.1 Sampling
Sampling should be performed In accordance with ISO 3165. The sample for test should be representative of the biik material and should be of an appropnate quantity Particular precautions should be taken when its properties are drechonaHy onentated. It is also recommended that a second sample is taken and held in reserve in case a repeated determination Is necessary.
8.1.1 ObtainIng a test sample
Since the material from which the sample for test is taken may be in a variety of forms, different subsampling methods are appropriate as follows.
a) From a block
Several pieces about I an3 may be taken in order to represent different zones from within the block. The pieces may be cut with a saw or core dnll or crushed. There is a possibalty that saw or crushing marks can be interpreted as pores If coarse pores are of particular interest. poleh the surface of the pieces with a medium of 10 pm maxaiium parlide size II fine pores are of particular interest, test the sample ii the as-sawn condition and Ignore data from pore diameter greater men 125 pm. Polished test pieces should be washed to remove adhering particles, which can affect the sample mass and block its pores. The sample should be dried to constant mass. For materials subject to hydration, wash with a non-aqueous liquid.
ISO 15901-1 pdf download – Evaluation of pore size distribution andporosimetry of solid materials by mercury porosimetry and gas adsorption— Part 1: Mercury porosimetry
