Ceramic are one of the oldest materials known to man and we have been finding new uses for them for centuries. Although most people think of pottery and tiles when they think of ceramics there are actually a wide variety of ceramic materials. Ceramic materials have become widely used for a number of industrial purposes and one of the most widely used is porous ceramics. There are number of reasons that porous ceramics are used instead of other materials but the biggest is that since they are inert they don't react with any other materials. This makes them ideal for testing and filtering purposes.
Porous ceramics are ceramic materials that have pores in them that are filled with a fluid. Broadly speaking there are two main types of porous ceramics, open pore and closed pore. An open pore ceramic will allow a fluid to move through an open pathway from one surface to the other. A closed pore ceramic has pathways that are blocked and don't allow the fluid to move to the other channel.
Porous ceramics can also by subdivided into hydrophobic and hydrophillic. Hydrophobic ceramics repel water, since there is no capillarity they can't wick water into the pores. Hydrophillic ceramics do have capillary forces and can pull fluids into the material.
Hydraulic conductivity is how porous ceramics are rated, it is a measure of the rate at which a liquid can be transported from one surface to another at a known pressure. This is largely related to the size of the pores and it needs to be considered when selecting a porous ceramic material.
One of the major uses of porous ceramics is to test the water levels in soil. They are widely used in agriculture to test things like field drainage and moisture retention. These are of critical importance to the farmer and he needs to know these things in real time so he can make adjustments in order to maximize his crop. Porous ceramics allow him to do just that.
Porous ceramics are also widely used as filters, particularly to filter solid particles out of liquids. They are ideally suited to this because unlike paper or membrane filters they can withstand a much higher pressure or suction. This means that they can be used in a wide variety of filtering applications in which other filters can't be used. Porous ceramics also have the advantage of having pore sizes that can be finer than those found in other filters so that smaller particles can be filtered out.
Another common use for porous ceramics is as an aerator. Aeration is the process of adding a gas to a liquid, it is important in a number of industrial processes. When you do this the gas will create bubbles in the liquid, in most applications it is important to control the size and number of those bubbles. A porous ceramic is the ideal material for this task.