Plasma-coated powders

Other potential applications are ceramic powders coated with their sintering aids, zirconia coated withyttria stabilizer, tungsten carbide coated with cobalt, or nickel, alumina abrasive powders coated with a relatively brittle second phase such as MgAl204 and plasma spray powders without the segregation of alloying elements. 

A Philips Environmental-SEM/EDX (Phihps XL30) was used to measure the morphology on untreated and plasma-treated powders. The powders were fixed on the sample holder by double conductive adhesive aluminum tape, and then gold-coated. Secondary electron images were recorded with the scanning electron microscope (SEM) using a 15 keV acceleration voltage. 

Figure 6.8 Spatial variation of the phase composition and the crystallinity of APS-HAp coatings incubated for 8 weeks in r-SBF (SBF-H, Table 7.8) as a function of the grain size of the precursor hydroxyapatite powder, (a) Coarse captal 90 powder (Plasma Coating...

Besides the chemical industry, sihcon is used as a powder in the ceramics (qv) industry for the production of sihcon carbide and sihcon nitride parts (see Advanced ceramics). Sihcon powder is also used as an explosive for defense apphcations and in the refractory industry for plasma spraying with other oxide mixtures (see Refractory coatings). 

The use ofDa plasma synthetic route can lead to materials with advantageous new physical characteristics such as high surface area (eg TiOp), spherodised powders and sprayed-on coatings. 

Interconnects are formed into the desired shape using ceramic processing techniques. For example, bipolar plates with gas channels can be formed by tape casting a mixture of the ceramic powder with a solvent, such as trichloroethylene (TCE)-ethanol [90], Coating techniques, such as plasma spray [91] or laser ablation [92] can also be used to apply interconnect materials to the other fuel cell components. 

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