Abstract
The effects of very small amounts of components were investigated by means of X-ray diffraction, scanning-type electron microscope and infrared absorption spectrum, and the following results were obtained:
(1) There are several remarkable effects of very small amounts of components on the growing rate of nitride, and it was clarified that particularly oxides of alkaline earth metals, transition elements and vanadium have excellent promotion effects of nitridation reaction.
(2) The crystal phase and form of silicon nitride coming from the differences of the kinds of very small amounts of components are not definite; for example, by the addition of alkaline earth metals, silicon nitride of α-phase is preferentially produced, and by the addition of vanadium, that of β-phase is preferentially obtained.
Furthermore, the crystal form is diversed such as in the whisker-like form, sea urchin pipe-like form, or in the hexagonal crystal form.
(3) The optimum addition amount of minute components to promote the nitridation reaction is different according to the kind of added substance, but it was recognized to be in the vicinity of 2.0wt%.
(4) The aspect of contribution of minute components to the nitridation reaction was made clear from the infrared absorption spectrum of the intermediate product in case of Fe2O3 addition.
