Carbides and Other Advanced Ceramics

The carbides are classified as a ceramic material. Some other ceramic materials related to the carbides are the nitrides, oxides and borides. The usual properties of the carbides and others are high strength, high temperature resistance and very good wear properties. You will find these used in circuits, engine applications, turbine blades and areas where corrosion is prominent.

Description of Ceramics

What is a Ceramic?

A ceramic material contains both metallic and nonmetallic elements. They are used in more applications than you may think. For example, you see it in bricks that surround your home, glass, pottery, cooking ware and even the catalytic converter in your automobile exhaust system where it removes harmful elements. They have good properties for high temperature areas, wear, good electrical properties, heat dissipation, long life, strength and hardness, is non corrosive and is relatively lightweight. The disadvantage to ceramics is that they are brittle, not good in high stress areas and they can be very expensive to manufacture for some uses.

As you can see, ceramics have many benefits to them with only a few shortcomings. The ones I would like to illustrate here are very modern ceramics. This denotes high price and advanced applications. These ceramics are sometimes used in conjunction with other materials, usually being metals, and are generally too expensive to produce in large quantities.

(Please note that there are many processes and treatments that are involved in manufacturing ceramics. I would simply like to show how just a few of them are used now and why.)

Types of Advanced Ceramics

Alumina(Aluminum Oxide)

Alumina is used in areas of very high operating temperatures. Its best properties are its melting temperature which is higher than steel and its insulating capabilities. Alumina is used to regulate circuits and insulate spark plugs and is used in factories to carry molten metal which obviously needs a high melting point. It is also being found useful in humans for dental and bone fillers.

Boron Carbide

This substance is very hard and unusually lightweight (notice that Boron and carbon are low on the Periodic Table of Elements). Its best applications are resisting abrasion and is used in improving the protection for bulletproof armor. Oddly, this is one material that demonstrates poor toughness at high temperatures.

Silicon Carbide

This ceramic is my showcase material. In the figure below, you see how its application is best used as a a coating for the cylinder walls of a high performance motorcycle engine. Its high temperature performance is outstanding and SiC also used as a particulate in composite materials.

Silicon Nitride

This ceramic is similar to the carbide mentioned above, although its oxidation resistance and high temperature performance are lower. It has been used as a coating on ball bearings used in high temperature areas. For more info about Silicon Nitride look here.

Titanium Boride

Titanium itself is a very tough substance and when combined with Boron as a ceramic material, it used in strengthening bulletproof armor and blades to turbine engine in aircraft's.

Charles Norwood 4/29/96

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