LYCOS RETRIEVER 
Beryllium: Beryllium Oxide
built 438 days ago
Beryllium is one of the lightest of all metals, is steel gray in color and has one of the highest melting points of the light metals. Beryllium and its salts are toxic and must be handled with care. At normal temperatures, beryllium resists oxidation in air, although its ability to scratch glass is probably due to the formation of a thin layer of the oxide. Its modulus of elasticity if one third greater than steel.
Source:
Beryllium Oxide (BeO) is a space age technical ceramic material that offers a combination of desirable properties not found in any other material. Distinguished by excellent high heat and thermal conductivity, it retains dielectric constant, loss factor and dielectric strength in the range of most electrical insulators. Along with good mechanical strength and stiffness to weight ratios, this unique combination of properties provides designers with a material that can reduce the size of heat generating circuitry while retaining essential high power capability and improved thermal stability.
Source:
Beryllium has one of the highest melting points of the light metals. The modulus of elasticity of beryllium is approximately 1/3 greater than that of steel. It has excellent thermal conductivity, is nonmagnetic and resists attack by concentrated nitric acid. It is highly permeable to X-rays, and neutrons are liberated when it is hit by alpha particles, as from radium or polonium (about 30 neutrons/million alpha particles). At standard temperature and pressures beryllium resists oxidation when exposed to air (although its ability to scratch glass is probably due to the formation of a thin layer of the oxide). The speed of sound in beryllium (12,500m/s) is greater than in any other element.
Source:
Beryllium Oxide (Beryllia) substrates have thermal conductivity of 260 W/mk - that makes it the desirable material for high power microelectronic applications. Until fairly recently, this has been the case but now there is a controversy! Is BeO safe? Judge for yourself.
Source:
Beryllium dust and fumes are toxic. In the 1990s, the International Agency for Research on Cancer classified beryllium as a human carcinogen. Workers in facilities where beryllium is mined or used have had an increased rate of lung cancer and beryllium disease. Beryllium disease results from exposure to beryllium dust or fumes from beryllium metal, metal oxides, alloys, ceramics or salts.
Source:
Because of the safety controversy and ... the cost, Beryllium Oxide has lost its popularity and Aluminum Nitride is replacing BeO in numerous applications. Aluminum Nitride substrates are more expensive than 99.5% Alumina Ceramic substrates but not that drastically.
Source:
MORE ABOUT
Beryllium Oxide