Beryllium electrical resistivity

Diamondlike Carbides. SiUcon and boron carbides form diamondlike carbides beryllium carbide, having a high degree of hardness, can also be iacluded. These materials have electrical resistivity ia the range of semiconductors (qv), and the bonding is largely covalent. Diamond itself may be considered a carbide of carbon because of its chemical stmeture, although its conductivity is low. 

Beryllium oxide shows excellent thermal conductivity, resistance to thermal shock, and high electrical resistance. Also, it is unreactive to most chemicals. Because of these properties the compound has several applications. It is used to make refractory crucible materials and precision resistor cores as a reflector in nuclear power reactors in microwave energy windows and as an additive to glass, ceramics and plastics. 

The electrical conductivity of beryllium is dependent upon both temperature and metal punty. It vanes at room temperature between + 42 7 (International Annealed Copper Standard). Electrical resistivity of 4.266 10 3 ohm m at 25°C has been reported. 

In modem electronic devices there is a need to manufacture materials which have high thermal conductivity and a high electrical resistance. The data in the Table 5.19 show that such a requirement can be easily fulfilled using boron nitride or beryllium oxide. Both fillers have excellent thermal conductivity and they are electrical insulators. 

Beryllia Beryllium monoxide Beryllium oxide Beryllium oxide (BeO) Bromellete CCRIS 83 EINECS 215-133-1 Gluoina HSDB 1607 Natural bromellite Thermalox Thermalox 995. Used in manufacture of beryllium oxide ceramics, glass in nuclear reactor fuels and moderators electrically resistive catalyst for organic reactions. Electrical conductor but thermal insulator. Light amorphous powder mp = 2530 very sparingly soluble in H2O. 

Beryllium oxide (BeO, beryllia) is the only material apart from diamond which combines high thermal-shock resistance, high electrical resistivity, and high thermal conductivity at a similar level. Hence its major application is in heat sinks for electronic components. BeO is highly soluble in water, but dissolves slowly... 

Beryllium oxide BeO BeO, synonym berylUa, is an electrical insulator like a ceramic, but conducts heat like a metal. The electrical resistivity is larger than 10 S3 cm... 

Beryllium is also used as a missile part and in other weapons. Owing to both its high thermal conductivity and high electrical resistivity, it is also used as a heat-sink material in electronic devices requiring good electrical insulation properties. In conclusion, some 60% of beryllium consumption is as a constituent of alloys and oxides in electronic parts and some 20% in the same form for electrical components. Approximately 13% is consumed as an alloy, oxide, or metal in aerospace and defense applications, while the balance is used as an alloy, metal, or oxide for other purposes. 

Beryllium is obtained by electrolytic reduction of molten beryllium chloride. The element s low density makes it useful for the construction of missiles and satellites. Beryllium is also used as windows for x-ray tubes because Be atoms have so few electrons, thin sheets of the metal are transparent to x-rays and allow the rays to escape. Beryllium is added in small amounts to copper the small Be atoms pin the Cu atoms together in an interstitial alloy that is more rigid than pure copper but still conducts electricity well. These hard, electrically conducting alloys are formed into nonsparking tools for use in oil refineries and grain elevators, where there is a risk of explosion. Beryllium-copper alloys are also used in the electronics industry to form tiny nonmagnetic parts and contacts that resist deformation and corrosion. 

Other popular alloys of beryllium are those with copper metal. Copper-beryllium alloys contain about 2 percent beryllium. They conduct heat and electricity almost as well as pure copper but are stronger, harder, and more resistant to fatigue (wearing out) and corrosion (rusting). These alloys are used in circuit boards, radar, computers, home appliances, aerospace applications, automatic systems in factories, automobiles, aircraft landing systems, oil and gas drilling equipment, and heavy machinery. 

Injection molds are machined from a variety of tool steels and then hardened or in some cases plated with chromium, nickel, or proprietary materials. Large molds use prehardened tool steels because they cannot be hardened after machining. 124 Stainless steel is employed for some smaller molds, particularly those used for optical and medical parts and for corrosion resistance. Since they provide better heat transfer and, thus, shorter molding cycles, materials such as beryllium copper are used as inserts in critical areas. Injection molds are usually cooled or heated with water, although oil or electric heater cartridges are employed for high-mold temperatures. Mold-temperature controllers pump water into the manifolds and then into cooling fine machine into the molds. 

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