Effect of a titanium nitride interlayer on the densification, properties and microstructure of cermets based on alumina and nickel — Part 2: Microstructures
SEM microstructural analyses in conjunction with EDX and TEM microstructural analyses have been conducted with cermets based on nickel and alumina, the latter as such and with a chemical-vapour-deposited titanium nitride layer. It has been proved that there is excellent bonding at both the Al2O3/TiN and the TiN/Ni interface, whereas Al2O3 and Ni do not adhere to each other. This is the reason for the observation that the mechanical properties as well as the densification of cermets consisting of Al2O3 and Ni are enhanced by applying a TiN interlayer between the ceramic phase and the metallic phase.
Effect of a titanium nitride interlayer on the densification, properties and microstructure of cermets based on alumina and nickel — Part 1: Densification and properties
In order to manufacture cermets based on Al2O3 and Ni, Al2O3 particles were first coated with TiN by CVD and then mixed with pure Ni powder. The cermets were produced from the mixed powders by powder metallurgy processes. The relative density and the mechanical properties of the cermets are improved due to the presence of the TiN interlayer. The contribution of this interlayer to the mechanical properties of the cermets produced by hot-pressing is superior to that by pressureless sintering.
Archaeology and mud wall decay in a West African village
Abstract A detailed study of the processes of deterioration of mud walls and of the physical evolution and devolution of a contemporary West African village is seen to facilitate the location of decayed mud structures at a nearby archaeological site. Various climatic and pedological conditions at the site make it unlikely that such walls will be discerned. The archaeologist wishing to obtain the fullest and least biased picture of the settlement configuration of the ancient community should therefore heed all the inferential lessons to be had from a focused ethnographic investigation. Given similar climatic situations and practices of house construction, taphonomy and ethnographic analogies may both be necessary for a valid reconstruction of an archaeological settlement.