Machinable with ordinary metalworking tools
Macor® (machinable glass ceramic) has a continuous use temperature of 800°C and a peak temperature of 1000°C. Its coefficient of thermal expansion readily matches most metals and sealing glasses. It is non-wetting, exhibits zero porosity, and unlike ductile materials, won’t deform. It is an excellent insulator at high voltages, various frequencies and high temperatures. And, when properly baked out, it won’t outgas in vacuum environments.
Machining tolerances are surprisingly tight, up to 0.0005in. (0.013mm). Macor MGC can be machined to a surface finish of less than 20µin. (o.5µm) and polished to a smoothness of 0.5µin. (0.013µm). Configurations are limited only by available equipment and the experience of the machinist.
Sealing, joining and metalising
Macor can also be joined or sealed-both to itself and to other materials-in a number of ways; metalised parts can be soldered together and brazing has proved to be effective method of joining the material to various metals: epoxy produces a strong joint, and sealing glass create a vacuum tight seal. Even a straight forward mechanical joint is possible. It can be thick film metalised using metal inks, or thin film metalised by sputtering. An example of vapour disposition metalising is shown on the examples page. Metal coatings available are Gold, Silver, Copper, Nickel, Platinum, Chrome and Tungsten. Other materials are available on request.
Ultra-high vacuum environments Macor is used as an insulator or coil support and for vacuum feed-troughs. In these applications the conductive materials are supported by the Macor part and a compatible sealing glass is used to produce a vacuum-tight, hermetic seal.
Constant vacuum applications
Macor parts are found in spacers, headers and windows for microwave tube devices and as sample holders in field ion microscopes.
Over 200 distinctly shaped Macor parts can be found on America’s reusable Spacer Shuttle Orbiter. Retaining rings of Macor are used at all hinge points, windows and doors.Also, large pieces of Macor glass ceramic are used in a NASA spaceborne gamma radiation detector. For this application frame corners are joined by a combination of machined (butt-lap) mechanical joints and a sealing glass.
Since Macor is not dimensionally affected by irradiation, small cubes of the material are machined to a tolerance of one micron and are used as a reference piece to measure dimensional change in other materials.
Welding equipment manufacturers are using Macor as a nozzle on the tips of oxyacetylene torches. The material’s non-wetting characteristic means molten particles won’t adhere to and decrease the effectiveness of the nozzle.
Macor is used as an electrode support and burner block in several industrial high heat, electrical cutting operations due to its low thermal conductivity and excellent electrical properties.
Producers of medical components are intrigued by Macor MGC’s inertness, precise machinability and dimensional stability.
When you need the performance of a technical ceramic- (high use temperature, electrical resistivity, zero porosity) – and your application demands the ready fabrication of a complicated shape look at Macor. It will lower costs and substantially reduce the time between design and actual use.
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