Apparent Porosity (Ceramic)
Compute a ceramic's apparent porosity, AP = (wet mass − dry mass)/(wet mass − immersed mass)·100%, the volume fraction occupied by open pores (accessible to water), measured by Archimedes' method. Unlike water absorption (relative to mass), apparent porosity is relative to volume. Open pores reduce mechanical strength and increase permeability. Enter the wet, dry and immersed masses (hydrostatic weighing).
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Apparent porosity (ceramics)
The apparent porosity AP = (wet mass − dry mass)/(wet mass − suspended mass)·100% measures the fraction of the volume of the piece taken up by open pores — those connected to the surface, which water can penetrate. The calculation uses the ingenious Archimedes method with three weighings: the dry piece, the water-saturated (wet) piece and the suspended piece (weighed hanging inside water — buoyancy gives the total volume). The numerator (wet − dry) is the mass of water held in the pores = open pore volume; the denominator (wet − suspended) is the total volume of the piece (by Archimedes). Note the subtle but important difference with respect to water absorption: absorption is relative to the mass of the piece, apparent porosity is relative to the volume — two ways of looking at the same open porosity. Open pores are the villains of strength: they concentrate stress (each pore is a crack starting point, lowering mechanical strength) and they allow liquid ingress (staining, water that freezes and cracks the body). There are also closed pores (isolated, unreachable by water), which stay out of this account yet still affect density — which is why apparent porosity and total porosity differ. Enter the wet, dry and suspended masses.
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Bulk Density (Ceramic)
Compute the bulk (apparent) density of a ceramic, BD = dry mass/(wet mass − immersed mass), by Archimedes' method, considering the total piece volume (including pores). It is an indicator of the densification achieved in firing: higher bulk density means fewer pores and generally higher strength. Water density (1 g/cm³) is used in the hydrostatic weighing. Enter the dry, wet and immersed masses.
Sintering Relative Density
Compute the relative density of a sintered body, RD = (bulk density/theoretical density)·100%, the fraction of the maximum density (of the fully dense, pore-free material) the piece reached. It is the central measure of the degree of sintering: advanced ceramics aim for RD above 99% (almost pore-free) for maximum strength and properties. The residual porosity is 100% − RD. Enter the bulk (sintered) density and the theoretical density.
Water Absorption (Ceramic)
Compute the water absorption of a ceramic piece, WA = (wet mass − dry mass)/dry mass·100%, the amount of water the open pores absorb by immersion. It is the property that classifies ceramic tiles: porcelain (WA ≤ 0.5%, very dense and strong), stoneware, semi-stoneware, semi-porous and porous (wall tile, WA > 10%). The lower the absorption, the more sintered and resistant the piece. Enter the wet mass and the dry mass.
Vitrification Degree (Ceramic)
Estimate the vitrification degree of a ceramic, VD = (1 − WA/WA_green)·100%, comparing the current water absorption with that of the green (non-vitrified) material, as a measure of how much the glassy phase filled the pores during firing. Vitrification — the formation of molten glass that seals the pores — densifies the piece, lowers absorption and raises strength and impermeability. It is what turns porous clay into vitreous porcelain. Enter the current and green water absorptions.
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.