Archimedes density

2021-07-14T07:32:38Z

Ju.ebert:

The Archmiedes method uses the buoyancy of a ceramic specimen in water to measure its volume. The open and closed porosity can be evaluated separately.
The method is very simple and requires only a high-precision scale with a suitable frame (see pictures) and a beaker with water.

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First, the dry mass of the specimen is evaluated. Subsequently, the specimen should be infiltrated with water (use another liquid for hygroscopic samples) in vacuum to assure that open pores are filled with water. This step can be omitted if the open porosity is negligible.

[[File:19 Probe in Pan 01.jpg|center|thumb]]

Second, the buoyant mass of the specimen is evaluated. The sample is placed on a mesh or grid on the weighting frame of the scale that is placed within a beaker with water. Make sure that:
*The water is equilibrated, i.e. reached room temperature and had enough time to reach equilibrium gas concentrations
*The beaker does not touch the weighting grid or plate anywhere
*The mesh/grid including specimen is completely submerged and does not touch the beaker anywhere
*During handling, no drop of water is spilled anywhere on the frame or plate of the scale

[[File:22 Probe in Basket 02.jpg|thumb|center]]

Third (optional), the specimen is cleaned at the surface with a wet cloth such that no drops of water remain at the surface, but no water is removed from the open porosity (i.e. do not use a dry cloth!). The specimen is weighted again outside of water.

From these three masses, the density of the specimen is obtained by:

\delta_closed=m_dry*(\delta_H2O/(m_wet - m_buoyant)

\delta_all=m_dry*(\delta_H2O/(m_dry - m_buoyant)

For optimum results, the temperature of the water needs to be corrected for the temperature, e.g. according to [https://www.internetchemie.info/chemie-lexikon/daten/w/wasser-dichtetabelle.php this table]:
https://www.internetchemie.info/chemie-lexikon/daten/w/wasser-dichtetabelle.php

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2021-07-01T14:40:18Z

Ju.ebert:

You can't make it without materials, and you can't make materials without processing. This phrase holds for all material classes, and particularly for ceramics.

Research and development in the field of ceramics involves researcheers form various fields, e.g. materials scientists, chemists, physicists, electrical and mechanical engineers. Beyond different fields, researchers are of very different education and carreer background, e.g. Bachelor/Master students, technicians, laboratory assistants, PhD students and Postdocs.

To date, there are a few very helpful textbooks on processing of ceramics. Beyond textbooks and scientific papers, very little references elaborate the practical aspect of ceramic materials science. What are the important aspects of powder processing? How do I mix and mill raw materials? How do I shape a ceramic green body? How do I select the right sintering method? What are the guidlines to design a heat treatment for sintering? How do I polish my sample?

We all miss a general cooking book for ceramics. This Wiki provides such a platform. A list of mostly practical articles helps anybody working on ceramics to set up his lab work. Everyone is welcome to extend the articles or to create new ones!

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Archimedes density

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