Beryllium oxide is an amphoteric oxide having the chemical formula BeO.
Beryllium oxide is obtained by thermal decomposition of beryllium hydroxide and some of its salts (for example, nitrate, basic acetate, carbonate, etc.) at a temperature of 500 to 1000°C. The oxide thus obtained is a white amorphous powder .
Before sintering, the beryllium oxide powder is pressed, thermally annealed, chemically cleaned, and vibrocompacted. Further, by the method of slip casting, products of the required shape and size are obtained .
Properties and Applications
Beryllium oxide (BeO) has a unique combination of thermal, electrical, optical and mechanical properties that are used in a wide range of applications from thermal control systems and integrated electronics to high temperature refractory components and nuclear reactors. Beryllium oxide has no analogues among oxide-ceramic materials.
Ceramics based on BeO has a melting point of 2803 °K and has a thermal conductivity that exceeds that of many metals, second only to copper and silver. At the same time, the thermal conductivity of BeO is 10 times higher than that of Al2O3, and 1.5 times higher than that of AlN.
The dielectric constant is lower than that of aluminum oxide and nitride. In this connection, BeO is an excellent insulator with a volume resistance of the order of 10^14...10^18 Ohm∙cm, which depends on the purity of the material.
In addition to high heat resistance, BeO has excellent strength with high values of specific rigidity .
Pure beryllium, and many compounds & nbsp; This metal is very toxic and can cause great harm to humans and the environment if safety measures are not followed. However, pure beryllium is extremely rare, since when exposed to air, its surface is immediately passivated. Beryllium oxide is not as dangerous as pure beryllium, however, it is better to take some precautions.
It is better to touch products made of beryllium oxide only with gloves. The most dangerous is beryllium oxide powder, which is dangerous if it gets inside a person, for example, if it is inhaled, or if it is accidentally transferred from hands to face. In this regard, it is not recommended to mechanically process beryllium in non-specialized places (equipped with good hoods, special insulating boxes, etc.).
Perspectives of use
Our colleagues from the University of Reshetnev analyzed the prospects for the use of composite materials in mechanical engineering. In , materials reinforced with whiskers are considered. Whiskers are obtained by drawing the melt through spinnerets. Drawers are high-precision molds for drawing threads. The "whiskers" of aluminum oxide, beryllium oxide, boron and silicon carbides, aluminum and silicon nitrides, etc. are used. 0.3–15 mm long and 1–30 µm in diameter. Reinforcement with "whiskers" can significantly increase the strength of other materials and increase their heat resistance.
In this article, we got acquainted with the method of obtaining ceramics based on beryllium oxide BeO, the applications and properties of this material. BeO ceramic is an excellent conductor of heat and is commonly used in thermal engineering as a high-temperature insulator. Precautions and prospects for using the material in the field of rocket science are considered.
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