Melting carbon content

Cast iron is the term applied to a wide range of ferrous alloys, whose principal distinguishing feature is a carbon content in excess of l -7<7o. The relatively low melting point of these alloys compared with that of steels and their tendency to expand slightly on solidification, which make them admirably suited for the production of components by casting, result from this feature of their composition. 

The polysilazanes were also melt spun, cured, and pyrolyzed to give silicon carbonitride fibers (Eq. 7). The carbon content of these fibers depends on the molecular composition of the polysilazane and the pyrolysis gas. When ammonia is used as reactive gas pure silicon nitride fibers will be obtained (Eq. 8) [14]. 

Metals which have been used (generally in inert or reducing atmosphere) as container materials are W (melting point 3422°C), Mo (2623°C), Pt (1769°C), Fe (1538°C), Ni (1455°C), Cu (1085°C), Au (1064°C), Ag (962°C). W and Mo do not react with many elements they must be protected however from air oxidation. Pt and Au cannot be used, owing to their reactivity, for melting metallic materials they are useful for other types of synthesis. Fe, of very high purity and with very low carbon content, could possibly be used for melting alkaline and alkaline earth metals and a number of their alloys. 

Benzene s molecular formula is C6H6, but it does not behave like hexane, hexene, or any of their isomers. One would expect it to be similar to these other six-carbon hydrocarbons in its properties. Table 4 provides a comparison between benzene, hexane and 1-hexene. The table shows that there are major differences between benzene and the straight-chain hydrocarbons of die same carbon content. Hexene s ignition temperature is very near to hexane s. The flash point difference is not great, however, there are significant differences in melting points. The explanation for these differences is structure which in the case of benzene is a cyclical form with alternating double bonds. 

The physical properties of the alkenes are very much like the physical properties of the alkanes. Table 1-8 gives comparisons of the melting points, boiling points, and specific gravities of die simpler alkenes. As with die alkanes, these physical properties increase with increasing carbon content. 

Crucible process. This process utilizes either wrought iron or open-hearth steel. The iron (or steel) is melted in graphite-clay crucibles in gas or electric furnaces, and pure carbon is introduced to bring the carbon content up to 0.8 to 1.5%. The steel thus produced is a uniform product of high quality and relatively high cost. It is used in making knives, razor blades, and tools requiring definite carbon content. 

---