Segregation, boron

A careful, quantitative study on grain boundary segregation, boron segregation in austenitic stainless steels of types 316L (with 206 at. p.p.m. of boron, and with <5 at. p.p.m. of boron) and Mo-free 316L (75 at. p.p.m. boron), has been reported by Karlsson, Norden, and Andren36 using a combination of TEM, FIM, AP and IAP techniques. Concen-... 

Figure 1.9. FIM micrograph showing boron segregation to a grain boundary in austenitic 316L stainless steel, together with atom probe composition profiles for boron (Karlsson and Norden 1988).

Interface segregations in other materials have also been investigated. Horton Miller41 studied segregation of boron to the grain boundary and antiphase boundary in rapidly solidified ordered Ni3Al alloy doped... 

Gu, H., Shinoda, Y., and Wakai, F., Detection of boron segregation to grain boundaries in silicon carbide by spatially resolved electron energy-loss spectroscopy , J. Am. Ceram. Soc., 1999, 82, 469-72. 

AGR fuel is transported to Sellafield in skips which are placed inside lidded containers using a dry inlet facility shared with Magnox fuel in the FHP. The container provides criticality control by segregation so boron addition to the water is unnecessary. The design of the lid allows containers to be triple stacked. After a minimum of 180 days cooling the elements are dismantled. 

Boron is another possible p-type dopant. The incorporation of boron into silicon epitaxial layers grown from a tin melt has been studied by Baliga [15] and McCann [16]. Boron is provided via the silicon source wafer and its incorporation is a function of both time and temperature. Its segregation coefficient from liquid tin into solid silicon is temperature dependent and increases with temperature. Therefore, the content of boron into the layer will be maximum at the interface and minimum at the final surface. This doping gradient can be used to create a drift field in the base layer of the... 

Interfacial Profiling. Neutron depth profiling is well suited for measurements across interfacial boundaries. Kvitek et al. ( ) and others (16,17,21,30) have studied profiles of boron implanted and diffused across the interfacial region of Si/Si02. Other NDP experiments (33,34) have been described for interfaces of silicon, silicon dioxide or metal on metal, where diffusion distributions and segregation coefficients were studied. 

Molybdenum has been known as excellent materials with good thermal stability and resistivity for chemical corrosion. Moreover it has shown that intergranular fracture in molybdenum was improved by a small addition of boron. The reason is supposed that boron segregates along grain boundaries,... 

Initial explanations of the extraordinary high-temperature stability of precursor-derived Si-B-C-N ceramics were presented previously by Jalowiecki et al. The authors investigated the microstmcture of boron-doped silicon carbonitride composites by HR-TEM and fotmd turbostratic BN(C) segregation occuring along grain boundaries of nano-sized silicon carbide and silicon nitride crystals. We suppose... 

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