What is the principle of heating pad?

Heating pad is the use of iron oxide heat release reaction to heat. In fact, is based on the occurrence of oxygen in the humid air in the oxygen corrosion of the principle. At the same time the use of activated carbon adsorption, in the porous structure of activated carbon storage of water vapor, water vapor into water droplets, out of contact with air and iron powder, sodium chloride in the catalytic reaction of the more rapid reaction of iron hydroxide , The release of heat.

The rate of oxidation of iron under natural conditions is slow. If this reaction is accelerated, for example, by increasing the surface area of the iron, the primary battery is formed using water, salt and activated carbon to promote the reaction, and the temperature required for the heat generating bag , as a heat source of heat bag.