Preparation And Properties Of Fe-co-ni-zr-mo-b-nd Amorphous Alloys

After Duwez.P had expended the preparation of glassy material to amorphous metal system at 1960s, many amorphous alloys were obtained. Amorphous alloys had received much concern because of their excellent properties. Fe-base bulk amorphous alloys had potential application for their high strength, high thermal stability, good soft magnetic and corrosion resistant properties.This paper studied the properties of the Fe-Co-Ni-Zr-Mo-B-Nd system amorphous alloys by means of changing the content of rare earth elements Nd. Fe-base bulk amorphous alloys with the diameter of 1.5mm and amorphous ribbons with the thickness of 30μm-50μm and the width of 2mm had been obtained by copper mould casting and Cu single roller spray casting using the raw materials in industry grade purity without purification. The glass forming ability, thermal stability and magnetic properties of the amorphous alloys were investigated by means of X-ray diffractometry (XRD), differential scanning calorimetry (DSC), vibrating sample magnetometer (VSM) and transmission Mossbauer spectroscopy (TMS).The XRD results showed that the glass forming ability of Fe56-xCo7Ni2Zr10Mo5B2oNdx(x=0,0.2,0.5,0.8 and 1.0) amorphous rods and ribbons samples was not deteriorated with the increase of Nd, the samples kept amorphous. It meant that the slight changes of Nd did not destroy the short-range order structure of samples.The thermal results showed that the supercooled liquid regions of rods and ribbons samples were wide (more than or close to 70K), and the thermal stabilities were high. The increase of Nd did not change the width of the supercooled liquid region regularly. The thermal stabilities of ribbons samples were better than that of rods. In the process of heating, the phase separation and the precipitation peak of initial grain of the ribbons samples had occurred before crystallization, the degree of disordering were much higher than that of rods. It was probably because that the cooling rate was higher while preparing ribbons samples.The magnetic results showed that the magnetic parameters (coercive force, saturation magnetization and magnetic permeability) of rods and ribbons samples of Fe56-xCo7Ni2Zr10Mo5B2oNdx(x=0,0.2,0.5,0.8 and 1.0) changed significantly with the changes of Nd. The soft magnetic properties of ribbons samples deteriorated with the addition of Nd, especially:the super-fine splitting of magnetic diploe had not been found in the Mossbauer spectrum of Fe55.5Co7Ni2Zr1oMo5B2oNdo.5 ribbons samples, the electric quadrupole splitting had been found only. The hysteresis loop was a beeline near x-axes. The sample showed paramagnetism. The change of the magnetic properties of rods samples was not significant, compared to the ribbons samples. The soft magnetic property of Fe55.5Co7Ni2Zr1oMo5B2oNdo.5 amorphous rod was the best.