A Friction Melting Metal

Radio Record, Volume II, Issue 49, 21 June 1929, Page 25

A Friction Melting Metal

N alloy, or rather, an amalgam which melts by mere friction, and without the application of external heat, is a very useful material for the radio experimentalist to possess. Not only is such an amalgam of great. service for cementing delicate crystals in their cups, but it’ is also obvious that here are a hundred and one other ses to which the amalgam may be put, especially by the experimenter. Mackenzie’s. Amalgam, for such is the name of the metal, contains three ingredients-lead, bismuth, and mereury. Two separate crucibles are needed for its preparation. In the first. of.

these is placed a mixture of 2 parts of bismuth and 4 parts of lead. Making the Amalgam. HE crucible is. then heated over a spirit lamp or gas burner until the contents have just melted. Immediately after this, the molten contents of the crucible are poured into a waiting crucible which contains 1 part of mereury (by weight, of course, and with reference to the weight of the molten mass of bismuth and lead). The contents of the second ‘crucible are stirred as rapidly as. possible, When solidification’ of the amalgam occurs, the contents of the crucible may be removed by giving the latter article a slight tap. The amalgam will present a silvery grey appearance. It

will be soft-almost plastic-to the touch. And the act of rubbing it along a stone, metal or other surface. will cause it to melt, or at the very least, to become as plastic as freshlymade putty. Necessary Precautions. (THERE are a few practical details which must be carefully observed if success is to be attained in the preparation of Mackenzie’s Amalgaysa. First of all, the. proportions of metal (all of them are by. weight) must he strictly adhered to. Again, in heating up the mixture of lead and bismuth, too high a temperature should not’ be reached, otherwise the bismuth would oxodise, and thus its proportional quantity in the metallic mixture would be reduced.

-__S i es Further,- before pouring the molten metals into the mercury, stir the contents with a small clean wooden stick, in order to ensure perfect mixing of the metals. And finally, before yua attempt te fuse ‘the metallic ingredients, be sure to see that their surfaces are perfectly clean, otherwise the fina] product will be contaminated with all kinds of impurities, and very unsatisfactory results will be obtained from it. Care must be taken when handling the mercury. as it has-a great affinity for metals, and if it comes into contact with metal the mercury = will quickly amalgamate with the former, and will spoil it for future use if it happens to be a valuable piece of cut lery or other: household artice.