Melt spinning method

The thickness of amorphous alloys is dependent upon production methods. Rapid quenching from the liquid state, which is the most widely used method, produces generally thin amorphous alloy sheets of 10-30 tm thickness. This has been called melt spinning or the rotating wheel method. Amorphous alloy powder and wire are also produced by modifications of the melt spinning method. The corrosion behaviour of amorphous alloys has been studied mostly using melt-spun specimens. 

Amorphous Ni-(40-x) at% Zr-x at% RE (x = 0, 1, 5 and 10 RE = Y, Ce and Sm) alloy ribbons of about 1 mm width and about 20 pm thickness were prepared by a single-roUer melt spinning method. The structure of the alloys prepared was confirmed by X-ray diffraction with Cu K radiation. The amorphous alloy ribbons were oxidized at 773 K in air for 5 hours and then reduced at 573 K imder flowing hydrogen for 5 hours. During this treatment the amorphous aUoys transformed to nickel catalysts supported on zirconia or zirconia-rare earth element oxides. 

Amorphous alloy ribbons of Ni-(40-x)Zr-xSm (x=0, 1, 3, 5, 7 and 10 at.% nominal composition) and Ni-(25, 35, 45, 55 and 65 at.%)Zr-5Sm were prepared by a melt-spinning method. The amorphous structure of these ribbons was confirmed by X-ray diffraction using Cu K radiation. Prior to catalytic reaction, the alloy specimens were oxidized in air at 773 K for at least 5 hours and subsequently reduced in flowing hydrogen at 573 K for at least 5 hours. 

Transmet Corporation manufactures flakes by a Rapid Solidification Technology. There are two variations of this method Melt spin and Spinning cup methods. In the Melt spin method, molten metal of any composition (pure metal or alloy) is driven through an orifice and the shape formed in the orifice (continuous sheet) is rapidly cooled on a chilling block. This metal sheet is cut into segments in the form of flakes (square and rectangular), flat fibers, and ribbons of desired... 

Fig, 6,18. Preparation of amorphous alloys by the melt-spinning method. 

Nonwoven flash-spuns Flash-spinning is a radical departure from the conventional melt spinning methods to produce nonwoven fabrics. In flash-spinning a 10-15 wt% solution of, for example HDPE in trichlorofluoromethane or methylene chloride. It is heated to 200C (392F) and pressurized to at least 4500 kPa (650 psi). This pressurized vessel is connected to a spinneret containing a single... 

Melt-spinning method The melt-spinning of PVC is conducted using an extruder [145], As PVC easily decomposes and carbonizes when heated for a long time, it cannot be transported in a molten state. Since viscosity of molten PVC is high, gear pumps cannot be used in the meltspinning of PVC. Also, special attention must be paid to its thermal stability and fluidity. 

The third characteristic is that samples prepared by the melt-spinning method can be substituted by a large amount of Co compared with the sintered magnets. The temperature dependence of the magnetic properties and the corrosion resistance, therefore, is improved by the addition of Co (Li and Graham 1990). 

Fig. 1. Schematic representation of the melt spinning method (a) external melt spinning, (b) internal melt spinning. The alloy is contained in a quartz vessel A and is induction heated by means of the coils B. The molten alloys is ejected by means of an argon pressure (D).

The melt-spinning method permits the eontinuous production of amorphous ribbons on a manufacturing scale at veloeities between 10-50 m/s. As such the method has received much attention in cases where the dimensions of the ribbons have to meet specific requirements. Details of the process have been studied by means of high-speed motion pictures (Walter, 1978 Hillmann and Hilzinger, 1978),... 

After separating the natural component from the blend, the remaining polyester may be garnered to obtain staple fibre products, for the manufacture of nonwoven products, or may be recycled in the melt spinning method. Formation of filament or films occurs without problems when the product of degradation is used as an addition to the standard polyester material. ... 

Figure 13.40 Dry and melt spinning methods of fiber extrusion.

Figure 1. Melt spinning method for producing metallic glass...

The metallic glass a-Zr2 d (batch identification RCB-5) had been produced by a previously-described helium atmosphere melt-spinning method from a stoichiometric crystalline alloy. The amorphous deuteride was prepared by slowly reacting 2 to 3 cm strips of the glassy ribbon with approximately one atmosphere of D2 gas over a total period of six days. 

Yoshino, K., Nakajima, S., Fujii, M. and Suginaoto, R.- 1. (1987) "Conducting polymer fibre prepared by melt-spinning method from fusible polythiophene derivative" Polym. Contmun. 28, 309-314. 

Kutlu et al. [151] have recently applied successfully a melt-spinning method to prepare LDH/HDPE nanocomposites using organo-LDH and a PE-g-MA masterbach compatibilizer, which is then mixed with HOPE in a microcompoxmder at 190°C and 100 rpm, Figure 6.2. Finally, small scale spin fiber production was carried out using a piston type spinning device. 

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