Metals and Alloys with Low Melting

Chlorides system is suitable to produce the rare earth metals or intermediate alloys with low melting point. The REM including La, Ce, Pr, and some mixed rare earth metal alloys have been produced from the chloride system. The disadvantages for the chlorides electrolysis lie in high hygroscopicity and volatility of electrolyte and low current efficiency. 

Type metal was an alloy with low melting point that was utilized to make the type for printing. The composition may be 81% lead, 15.5% antimony and 3.5% tin. The molten alloy expands on solidification and thus fills the moulds very well. This gives the type sharp edges. The technique has entirely been replaced by new printing methods. 

Elemental zinc was officially discovered in Enrope in 1746 when calamine (zinc silicate) was rednced with charcoal to produce the metal. However, zinc had been used for many hundreds of years before tMs discovery because zinc ores and copper ores were used to form copper-zinc brass alloys. The main sources of zinc are ores composed of sphalerite (ZnS), smithsonite (ZnC03>, and an oxide mixture of zinc, iron, and manganese called franklinite. These ores are roasted to form the oxides of the metals and then reduced with carbon to produce the elemental metals. Zinc combines with many different metals to form useful alloys. As we have seen, the combination of zinc and copper produces the brass family of alloys. The combination of zinc and nickel with copper produces alloys with a silver color called German or silver brass. Zinc is also used in solder alloys with low melting points. 

To further increase the electrical conductivity of conventional compounds and at the same time ensure a good processability at high filling degrees, at IKV fiber-filled thermoplastics are combined with metal alloys with low melting points to create a novel material [8]. These metal alloys are liquid during the processing phase and do... 

Typically, Be-containing alloys and intermetallic phases have been prepared in beryllia or alumina crucibles Mg-containing products have been synthesized in graphite, magnesia or alumina crucibles. Alloys and compounds containing Ca, Sr and Ba have been synthesized in alumina , boron nitride, zircon, molybdenum, iron , or steel crucibles. Both zircon and molybdenum are satisfactory only for alloys with low group-IIA metal content and are replaced by boron nitride and iron, respectively, for group-IIA metal-rich systems . Crucibles are sealed in silica, quartz, iron or steel vessels, usually under either vacuum or purified inert cover gas in a few cases, the samples were melted under a halide flux . 

The brittle, silvery, shiny metal was long considered the last stable element of the Periodic Table. In 2003 it was unmasked as an extremely weak alpha emitter (half-life 20 billion years). Like thulium, there is only one isotope. Bismuth alloys have low melting points (fuses, fire sprinklers). As an additive in tiny amounts, it imparts special properties on a range of metals. Applied in electronics and optoelectronics. The oxichloride (BiOCl) gives rise to pearlescent pigments (cosmetics). As bismuth is practically nontoxic, its compounds have medical applications. The basic oxide neutralizes stomach acids. A multitalented element. Crystallizes with an impressive layering effect (see right). 

Rotating electrode atomization may be applied to almost all metals and alloys since it does not require a crucible for melting and/ or pouring. In particular, high melting-temperature metals and alloys, such as Ti and Zr, are well suited for the process. However, the production cost is still a drawback associated with the process, since electrode production is generally more expensive than a metal melt. In addition, production rates are relatively low compared to other atomization processes such as gas atomization and water atomization. 

From the beginning of the 1930s, studies on a melt treatment by elastic oscillations were carried out in three main directions (1) the study of an effect of elastic oscillations of various frequencies with the aim to establish a mechanism of nucleation and growth of solidification nuclei in supercooled liquids, i.e. melts and solutions (2) the study of structure and properties of metals and alloys subjected to low-frequency vibration and (3) the study of an ultrasonic oscillation effect on molten metals. Significant research in this area was performed in the 1950s by Danilov, Kapustin, Polotskii, Sirota, and their associates on solidification of organic substances and a number of metals in ultrasonic field. 

An interesting set of investigations on an effect of ultrasound with pulsed and continuous initiation of cavitation on solidification of low-melting metals and alloys has been performed by Buxmann [15] in Switzerland. The results of studies on the ultrasonic treatment of melts of aluminum and its alloys have been published... 

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