Custom Engineered Ceramic Parts

• Choosing the Composition or Design
  
• Properties of Alumina Ceramics
  
• Properties of Zirconia Ceramics
  
• Properties of Sapphires
  
• Finishing: Machining, Polishing, Metalizing, and Brazing
  

Choosing the Composition or Design

Engineered ceramics are made from a number of materials including oxides, carbides, nitride, and composites. Ceramics are characterized by their ability to withstand high temperatures, good electrical resistance, dielectric strength, high hardness and abrasion resistance, and chemical stability. Many factors are involved in choosing the correct material for the application. The following is a brief description of material available. By clicking on the name, additional information can be obtained. These materials can be formed using several different methods, fired to high densities, and then can be precision machined, polished, and metalized, to exacting specifications.

Choosing the Composition

Oxide ceramics are the most versatile of the ceramic materials when considering cost and ease of forming and machining. They can be pressed, extruded or cast and "green machined" to near net size before firing. Aluminum Oxide is a versatile material with a number of compositions to choose from that have different physical properties that can be matched to the application. We can also select from Zirconium Oxide compositions that are known for their toughness and fracture resistance. Other oxide materials include Magnesium Oxide, Silica, quartz, and Thoria parts can be selected for their unique properties. Sapphire, single crystal alumina, is a material often chosen for its high hardness, transparency, thermal and electrical properties.

We also offer newer silicon nitride, sialons, silicon and boron carbides, titanium borides, magnesium and thorium oxides, and mixed oxides such as mullite ans spinel. The compositions have characteristics such as high toughness, excellent wear properties, and thermal shock resistance. For details of compositions and physical properties of materials, please contact us directly.

For special applications requiring properties such as windows used in high temperature or corrosive atmospheres, Sapphire can be the material of choice.

Choosing the Right Design

The design of the ceramic part is also very important in the successful use of ceramics. Ceramics are by their nature more are ridged and brittle than metals and they are also much stronger in compression than in tension. This means that the ceramic part must not only be designed to meet the physical requirements of the application, but also must be matched to the characteristics of the material as well.

In addition, the manufacturing methods available to form and finish the ceramic part must be considered. For example, a part that is designed too thin for the material's strength will have high breakage when manufactured. Too large of a part may also be difficult to manufacture.

Over designing the part or using unnecessarily tight specification will significantly increase the cost. Careful identification of the tolerances and property required are important considerations.

Each of the ceramics we recommend have their own unique properties and, of course, cost factors for both the material, the initial forming and any final precision machining or finishing of the part. To ensure success, careful consideration and balancing of all factors must be made at the initial stages of design.

Marketech's ceramic engineers provide design and product selection assistance to make ceramics work for your application.

Finishing Options

Once formed, engineered ceramics can be machined, polished, threaded, and metalized. Some materials lend themselves to these processes more than others, and other compositions are specifically designed for a machining or finishing process. For more information, click here for a description of machining, metalizing, brazing, and finishing of engineered ceramics.

Below are listed some of the proprietary and standard engineered ceramic compositions we offer.

Properties of Alumina Ceramics

Because of its high temperatures, chemical electrical and mechanical properties, relatively low cost, and ease of manufacture, alumina is the work horse of engineered ceramics. It is compounded with silica and other trace elements and is available in several common grade ranging from 92% to 99.7% Al2O3. Alumina can be formed by casting, extrusion, or pressing. For large size or smaller quantities, alumina is issotically pressed into chalk like blocks that can be "green machined" to a near net shape, fired and then "finished" machined to high tolerances. Special grades of alumina are often metalized and then brazed to metal parts.