Verneuil method

In the Verneuil method, the powdered sample is melted in a high temperature, oxy-hydrogen flame and droplets allowed to fall on to a seed crystal where they crystallize. This is an old method used originally to produce artificial ruby. Using the same method but using a plasma torch to melt the powder, can achieve even higher temperatures. 

Figure 2.1. Various forms exhibited by crystals, (a) Polyhedral crystals (b) hopper crystal (c) dendritic crystal (snow crystal, photographed by the late T. Kobayashi) (d) step pattern observed on a hematite crystal (0001) face (e) internal texture of a single crystal (diamond-cut stone, X-ray topograph taken by T.Yasuda) (f) synthetic single crystal boule. Si grown by the Czochralski method (g) synthetic corundum grown by the Verneuil method.

The Verneuil, or flame-fusion, method is illustrated in Figure 29.1. It is a well-established technique for growing single crystals of oxides that have high melting temperatures. The largest application of the Verneuil method is for the growth of sapphire and ruby. 

The FZ method shares many similarities with the Verneuil method. The main difference is that the source is a... 

Describe the Verneuil method for producing ruby. What are the advantages and disadvantages of this process ... 

Synthetic ruby 2 %Ct20 in a-Al203) for lasers is made industrially by the Verneuil method as are single crystals of corund itself, sapphire, rutile, spinels, and strontium titanate. In this method the oxide particles are dropped through a flame,... 

Various synthetic approaches have been applied to obtain stable and metastable Ga203 polymorphs, as either bulk crystalline phases or nanoparticles. Single crystals of the thermodynamically stable P-Ga203 phase can be obtained with and without dopants by using the Verneuil method, under oxidizing and reducing atmospheres [183,184]. 

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