Hot isostatic pressing is now an accepted material processing technique for theconsolidation of metal powders to near-net-shape components. This thesis examinesthe use of coatings as in-situ envelopes to overcome the problems associated withtraditional containerisation of powder. The application of metallic coatings by physicalvapour deposition, involving resistive and electron beam evaporation and ion plating,onto green powder metal compacts has been studied as a potential method forencapsulating powder metal products prior to hot isostatic pressing. The coatingstructures are discussed in terms of processing conditions and surface roughnessinfluence. The most promising approach is a combined sinter-hot isostatic, pressingcycle, which utilises the formation of a transient liquid phase to defect-heal thecoating during the sinter cycle prior to the application of pressure. The influence ofparticle size distribution on densification has also been studied. This included bothmonosized and bimodal powders. The results of this study has been incorporated intoa modified Ashby model computer program and it is shown that the model results ina shift of the dominance of the mechanism fields and gives good correlation betweenthe predicted and measured values of density.
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