Phase composition cathodoluminescence

Luminescence is a phenomenon originating from the emission transition of ions, molecules or a crystal lattice from an excited electronic state to a ground state or a state with lesser energy. Depending on the mode of excitation, several types of luminescence can be distinguished such as photo-, cathodo-, thermo-, chemo-, tribo-, crystallo-, bio- and X-ray luminescence. 

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In this chapter common methods to evaluate chemical properties and phase composition of bioceramic coatings will be briefly described that are available in many laboratories including X-ray diffraction (XRD), vibrational spectroscopy techniques such as infrared (FTIR) and Raman spectroscopy and nuclear magnetic resonance spectroscopy (NMR). These methods provide a host of information on bulk phase composition, degree of crystallinity and crystallite size. Some special techniques including cathodoluminescence serve to reveal intrinsic coating properties that cannot be assessed by conventional analytical techniques, for example to distinguish between amorphous calcium phosphate (ACP) and crystalline calcium phosphates. 

All of the Type A and B inclusions studied are surrounded by a layered rim sequence of complex mineralogy [21] which clearly defines the inclusion-matrix boundary. Secondary alteration phases (grossular and nepheline, especially) are also a common feature of these inclusions, suggesting that vapor phase reactions with a relatively cool nebula occurred after formation of inclusions. Anorthite, in particular, is usually one of the most heavily altered phases the relationship between Mg isotopic composition and alteration is discussed below. (See [12] for striking cathodoluminesce photographs of typical Allende alteration mineralogy.) Inclusion Al 3510 does not fit the normal pattern as it has no Wark-rim and does not contain the usual array of secondary minerals. 

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