464 W. P. TIeadden — Formation of the Alloys of 



Aet. LXIII. — A Study of the Formation of the Alloys of 

 Tin and Iron %oith descriptions of some new Alloys /* by 

 William P. Headden. 



About three years ago I had occasion to investigate some 

 tin buttons obtained in assaying tin ore by the potassic cyanide 

 method, and observed that the alloy obtained by oxidizing the 

 buttons with hydric nitrate and treating the oxidized mass 

 with potassic hydrate was not only significant in quantity, 

 ranging from one and a half to ten and a half per cent, but 

 varied in form also, though obtained under similar conditions 

 of charge and temperature. Subsequent investigations con- 

 vinced me that the same is true of dross obtained by melting 

 larger quantities of tin ore with anthracite dust, lime and 

 fluor spar in a graphite pot. As the latter method yields 

 larger quantities at less expense, the dross from such fusions 

 was used, as a rule, in my investigations. 



Of the buttons first investigated, the first yielded about 

 7 per cent of a non-magnetic alloy corresponding to the for- 

 mula Fe,,Sn 3 ; the second yielded a quantity of magnetic 

 alloy corresponding to the formula Fe 4 Sn 6 ; while the third 

 yielded a non-magnetic alloy, so small in quantity, however, 

 that no analysis was attempted, but its form differed from that 

 of the other two, and I had no reason for believing it to be 

 identical with either of them. Its form was that of a six 

 sided prism with etched and pitted basal plane which was 

 seldom perfect though always present. This was probably 

 an imitative form after an orthorhombic combination. 



The results of the investigation to which this led may be 

 briefly given as follows : i. e. that there is a series of stannides 

 of iron of which I obtained the following members, FeSn 2 , 

 Fe 2 Sn„ Fe a Sn 4 , Fe 4 Sn 5 , Fe 5 Sn 6 and FeSn— and in addition to 

 these, the following, Fe 3 Sn, Fe 4 Sn and Fe 9 Sn. 



Some of these have been described before, but the descrip- 

 tions given by the various investigators agree in assigning 

 them properties, some of which differ widely from those 

 observed in my alloys. Those previously described are FeSn 3 , 

 ISToellner; FeSn, Deville and Caron; Fe 3 Sn, Lassaigne, and 

 Fe 4 Sn, Bergman. The first of these has more recently been 

 studied by A. C. Oudemann, Jr. ISToellner says that FeSn, is 

 insoluble in hydric chloride. While Oudemann makes no 

 definite statement on this point, merely stating that he prefers 

 to use hydric nitrate in separating it from the excessive tin 

 leaving it to be inferred that he found it at least difficultly 



* Abstract of article read before Colo. Scientific Society — Address of retiring 

 President for 1891. 



