Hi

Greetings

In metals the water absorption literally nil. They can react with water moisture and forms their own oxides. But they can store the water in it.

Eg. Steel. The mild steel will react with moisture and forms rust. We cant take the moisture separately.

But in woods the moisture will be absorbed via void contents in cellulose. By heating we can remove the moisture frim woods.

In pomymers

Hydrophobic polymers do not absorb water generally. Pymers will never react with water. While processing the polymers they may absorbe moisture and just retain them inside. While heating they can be removed.

Density and Porosity plays a vital role.

Metals and alloys are less prone to water or water vapor absorption at room temperature.

But at higher temperature, density decreases and porosity is locked which leads to more absorption.

Wood is an organic material contains lignin and cellulose material which is prone to absorption. Permeation is higher in this case.

Plastics having cross linked chains have lesser absorption.

Ceramics are less prone to absorb water or water vapor due its complex crystal structure.

Absorption of water and water vapor is influenced by the crystallographic structure.

Metals actually tend to have some non-zero rate of diffusion for water vapor, and generally do carry micro voids and porosity which traps some non-zero level of moisture. If you think about it delayed hydride cracking is generally due to dissassociated hydrogen from water chugging it's way down grain boundaries and stress risers.

But in the macro sense, no metals generally are not porous and don't "hold" moisture in any great quantity relative to their own weight or volume.  but you won't really off gas any moisture from a piece of metal in anything above maybe a few parts per million.  Preheat just helps give you above the temperature where condensation would play a factor and also helps drive away surface contaminants by burning them off.

The answer is 'yes'. However, the question that you should be asking is 'To what extent will metals absorb water?' The answer to this is practically zilch or 4/5ths of nothing.

Alan F Rawle Thanks for the answer. Is there any article or text that I could use as a reference in my thesis?

Depends on the metal. Metallic sodium (and potassium and calcium and caesium) will 'interact' with water. Amalgamate aluminum with Hg and it'll react with water. You need to be much more specific. Iron will rust in air in the presence of moisture etc. Take a look at the attached.

Capillary attraction can take place with a film of water. See:

Adhesion and cohesion http://tinyurl.com/zwb2wlh

My parents were in the iron and steel business. My mother would iron and my father would......

Alan F Rawle I've been reading this article you sent to me. But i'm looking for data about water/vapor diffusion on metallic solid faces. Specifically, I need these data for metals like gallium, mercury, iron...

Best.

V R Arun Prakash thanks for the answer.

How can I find the data about water absorption in metal?

Dr. Alan F Rawle gave a very good answer, but let me add small point as well.

Consider the condition the metal will be used, T, pressure, weather the metal will be in contact to a) electricity {electrolytic processes may occur}, b) aggressive gasses/vapours {chemical corrosion}, c) in contact to other metal {galvanic processes may occur}. gallium, mercury, iron will not take a water into as the water molecule size is big and can not go in. but may absorb the vapours and hold depending on T and partial pressure and surface pomposity, as well as the presence of defects at material grain boundary.

Best

Metals will react with water while biomas and woody materials have high affinity for water absorption.