On the magnetic qualities of some alloys not containing iron

The exhibition by one of us (Mr. R. A. Hadfield) at the British Association Meeting at Cambridge in 1904, of a sample of a magnetic alloy first prepared by Dr. Heusler, composed of copper, aluminium, and manganese, having aroused considerable interest, we felt that the quantitative measurement of the principal magnetic constants of such a material would be of very considerable interest. We, therefore, undertook at the earliest moment experiments with this object in view, and the following paper contains an account of the preliminary results obtained. For the purposes of exact magnetic measure­ments it was necessary to prepare the material in the form of homogeneous rings of regular form. This part of the work was undertaken at the Hadfield Steel Works, Sheffield, and in the early part of January, 1905, two such rings of alloys not containing iron were sent to the Pender Electric Laboratory of University College, London, for the magnetic tests. These two rings were respectively numbered No. 1871 and No. 1888/7. Their chemical constitution was as follows:—The ring No. 1871 had the following composition: Manganese, 22·42 per cent.; copper, 60·49 per cent.; aluminium, 11·65 per cent. There is a certain amount of intermingled slag, probably 2 or 3 per cent., mostly consisting of MnO and SiO2 and slight traces of other metals. Analysis showed that there was present also: Carbon, 1·5 per cent.; silicon, 0·37 per cent.; and iron, 0·21 per cent. Hence it may be said that nothing but a trace of iron occurs in this sample of alloy.