I have developed five compositions using powder metallurgy and reinforments in increasing weight percentages were added to the base matrix. And the density of the compacts from base matrix to the final reinforced sample is in decreasing order which also indicates that porosity is in increasing order. Finally , the results are to be justified with respect to the increasing pattern of porosity and I am having difficulty in finding porosity because of limited resources. If any one could help me out as to how to reflect the relative increase in porosity, I would be obliged.
Thanks
If all the porosity in the samples is open porosity (pores that connect to the atmosphere) you can use the Archimedes method (provided you thoroughly degas the sample) to determine the actual density and compare it to a calculated volumetric density. The difference in densities times the mass of the sample should be the volume of the porosity. If the sample contains closed porosity (not open to the atmosphere) you will have to first compare the apparent Archimedes density with the theoretical density of the material for the same volume to get the closed porosity percentage. It can be very tricky to determine the volume of a sample that contains both closed and open porosity accurately.
The approach you use depends on your purposes in knowing the porosity. Are you going to use density measurement as a quality control tool for a product on which you can do some more research than you are doing, because you can sacrifice a sample or two, despite limited resources. Metallography is a very useful tool to find out what is going on in the materials of different composition. Using that tool compared with the density measurements recommended by Paul Taylor would provide you with the information you need, whatever your long term purposes.
Are sintered the pieces?
- You can make various cross sections and perform processing imagenes.-
- You can weigh the piece, then immersing it in a fluid (water) to leave a long pores are filled time, reweighed and compare different pieces.
Hi Sanjay,
The density or porosity of the sintered samples can be measured according to ASTM standard B962-15 which is based on Archimedes' method. The steps to perform this method are very simple.
1. Boil the samples for 40 mints in distilled water for degassing purposes.
2. Immerse the samples in the water to fill out any pores. and check the immersed weight = w1
3. take out the immersed samples and tap off the water from the top bottom surfaces gently and measure the weight , w2.
3. dry the samples in an oven for 1 hr and note the weight, = w3.
then make the following calculation:
exterior volume of samples , V = (w3-w1)/ density of water (~1.0 g/cc)
Bulk or Archimedes density = (w3)/ V
Volume of pores , vp = (w2-w3)/density of water
Apparent porosity (%) = vp/V
Relative density (%) = Bulk density / theoretical density.
In order to preform such method you need to get an equipment/set-up as you can see in attached image, which is very simple to make or use.
Hope it helps.
Good luck,
Khurram
About the experimental measurement of the bulk density for porous samples, using the Archimedes method, you may check my answer at: https://www.researchgate.net/post/How_do_i_calculate_for_percentage_porosity_in_a_ceramic_material/1
The most accurate way to determine porosity in a sintered disc is to measure the pressure drop and back-calculate for the porosity. I have developed a novel technique to do this and refer all readers to the following link www.wranglergroup.com/UPPR. Under the UPPR tab on my web site you will find examples of published papers in which I provide the necessary corrections to validate porosity in sintered discs made from powdered metals.
Dear Sanjay porosity is differ from density ,porosity measured by wetting the pellets with water then weight it.After dry the pellets with Caco3 for a time and weight the pellets so the differrence in weight represent the porosity.
Hi Dear Resarchers
As we know the theoretical density of one material or composite. by measuring the density of the sample by using the Archimedes method. the difference between theoretical density and measured is the amount of porosity in the sample.
Best Regards
Dear sanjay mohan Sharma
I woudl suggest that Infrared Thermography is a good option. I would like to help you with the following research article:
https://doi.org/10.1177%2F073168449201101203
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