Effect of carbon on the nitridation behavior of aluminum powder

Abstract

The effect of carbon on Al powder nitridation was investigated from an atomic-scale chemical and crystallographic viewpoint. Carbon delays the initiation of nitridation and melting of Al powder, possibly because of its insulation effect. Therefore, carbon provides a pathway through which a constant supply of nitrogen gas is provided before molten Al powder is fully consolidated. Carbon also alters the nitridation mechanism by acting as a reaction agent of aluminum oxides and providing the path for nitrogen gas for constant nitridation, thereby stimulating the formation of the AlN with a typical triplet band structure. As a result, when carbon covers the entire surface of the powder, about 85% nitridation can be achieved. (C) 2016 Elsevier B.V. All rights reserved.