268 KEPORT— 1889. 



Mr. Turner's paper, read before this Association at Bath last year, 

 described experiments with steel containing from '10 per cent, to '50 per 

 cent, silicon, and the details were fnlly given in the ' Report,' 1888, p. 69. 

 The writer was asked by Mr. Turner and your Committee to investigate 

 the effect of higher percentages of silicon. 



The subject of alloys of iron and silicon has for some years occupied 

 the writer's attention, but it is only lately that rich cast-iron alloys of 

 silicon, i.e., ferro-silicon, have been obtainable ; and even now they cannot 

 compare in richness of silicon with that of the manganese in ferro-man- 

 ganese. The highest ferro-silicon yet made contains not more than about 

 18 per cent, to 20 per cent, of silicon. Fortunately, however, owing to 

 the peculiar fact, noticed more fully further on, as to its lowness in carbon, 

 this is much better fitted for experimental work as compared with, say, 

 20 per cent, ferro-manganese Such percentage of silicon, though, com- 

 paratively speaking, not so high, is sufficient to enable a suitable experi- 

 mental material to be made, i.e., a resultant material not containing too 

 much carbon to interfere with an examination of the effect of the metal- 

 loid silicon upon the metal iron. Thus, while in the case of rich spiegel 

 or ferro-manganese the carbon present amounts to some 5 per cent, or 

 6 per cent., the 20 per cent, ferro-silicon, on the contrary, contains 

 comparatively little carbon — always under 1^ per cent., and often under 

 ^ per cent. ; so that by means of this cast-iron alloy, when further diluted 

 or mixed with pure iron, the malleable material or steel produced practi- 

 cally contains but little carbon. The curious fact that ferro-silicon alloys 

 as they rise in silicon diminish in carbon was first noticed in some 

 laboratory experiments eighteen years ago by Mr. Edward Riley ; this 

 will be again referred to further on. Whilst the scope of the experiments 

 described in the present paper is in no way to deal with material other 

 than malleable compounds of iron and silicon with small quantities of 

 iron and manganese, it may be useful to give some general reference to 

 previous experiments. 



The only commercial employment of silicon with other metals is that 

 of silicon bronzes. It is stated to act upon the copper in a similar manner 

 to phosphorus. The qualities of such alloys are great strength and 

 tenacity, high electrical conductivity, and resistance to corrosion. Wii^e 

 made of this material is stated to have a conductivity of 80 per cent., and 

 a tensile strength of about 36 tons per square inch. 



Mr. Warren, in a recent number of the ' Chemical News,' states that 

 silicon when in the nascent state converts platinum into a brittle silicide ; 

 or, by heating graphitoidal silicon in contact with platinum to a full red 

 heat, combination at once takes place, resulting in a brittle regulus con- 

 taining as high as 10 per cent, silicon, which is fusible at a red heat, and 

 breaks with a crystalline fracture. 



Silver and gold are reported as not presenting any great affinity 

 towards silicon, but on heating a mixture of potassium silico-fluoride with 

 either silver or gold in an amorphous condition to a high temperature, a 

 well-fused regulus of silicide of the metal may be obtained. In the latter 

 instance an alloy containing 5 per cent, of silicon is almost as brittle as 

 antimony. Silver when alloyed with 10 per cent, of silicon is stated to 

 have a slightly red tint. 



Rich cast-iron alloys of silicon are now usually described respectively 

 as ferro-silicon and silicon-spiegel, the latter containing manganese in 

 addition to silicon. Silicious alloys of cast-iron were usually known as 



