High-pressure gas atomization

Figure 3.32. High quality, nearly spherical powder prepared by high-pressure gas atomization from the melt and proper sample length, L. The x-ray powder diffraction data were collected from a continuously spinning sample (20 mm diameter and 1 mm deep) prepared as shown in Figure 3.22. Notations are the same as in Figure 3.29. The powder contains a small fraction of a second phase, which is identified by the series of vertical bars shifted downwards. The inset shows the scanning electron microscopy image of the powder morphology. (Powder courtesy of Dr. I.E. Anderson.)...

Pattern A was collected from a LaNi4 85Sno.is powder prepared by high-pressure gas atomization and then heat treated at 950°C for 5 min. The compound has a hexagonal crystal structure with unit cell dimensions a = 5.04, c = 4.01 A. 

We have seen this powder diffraction pattern several times throughout this text. The histogram collected from the nearly spherical LaNi4.85Sno.15 powder, produced by high pressure gas atomization from a melt, was used to illustrate both the quality of x-ray diffraction data and as one of the examples in the ab initio crystal structure solution. To demonstrate the Rietveld refinement of this crystal structure we will begin with the profile and unit cell parameters determined from Le Bail s algorithm Table 6.3) and the model of the crystal structure determined from sequential Fourier maps as described in section 6.9 and listed in Table 6.8. 

In this section, we report our recent results on the synthesis of Mg-based amorphous alloys in ribbon, bulk and powder forms by various preparation techniques such as melt spinning, metallic mold casting, high-pressure die casting and high-pressure gas atomization, and on their thermal, mechanical and chemical properties. This review also deals with the microstructure and mechanical properties of Mg-based alloys produced by warm consolidation of the atomized powders. 

LSafety note In atomic spectroscopy, thej., fiu se of high- pressure gas sources, e.g.L.- . Ry]iiiders,3affB )particWar[y,haza2lou sr. Alvyaysjoirsolt a-demonstrator otC Itechpician before use - ... 

Safety note in atomic Spectroscopy, the use of. high-pressure gas sources, e.g. cylinders, an be particularly hazardous.. Always consult a demonstrator or technician before use. ... 

A flame atomizer contains a pneumatic nebulizer, which converts the sample solution into a mist, or aerosol, that is then fed into a burner. The same type of nebulizers that are used with ICPs are used with flame atomizers. The concentric nebulizer is the most popular. In most atomizers, the high-pressure gas is the oxidant, and the aerosol containing oxidant is subsequently mixed with the fuel. 

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