The mechanism of the sintering of compressed metal powders, 90 parts of copper, 10 parts of tin and 2 parts, of graphite, was studied in detail by measuring density, hardness, electric resistance and expansion, and also by X-ray analysis and microscopical examination.
Theresult appeared to justify that:
(1) During the stages of the sintering process, one or more transient phases such as γ and other tin rich phases are produced and these powders, prepared by electrolysis, exclude the absorbed hydrogen gas. These two phenomena play a marked effect on the diffusion.
(2) The heating of about 3 hrs. at 650-700° is sufficient to cause complete diffusion of the compressed powders used in the investigation.
(3) The results obtained with graded particles showed that the interdiffusion taking place in a given time is greater, the smaller the size of the particle. This result harmonize with the observation of the inter-diffusion of copper and zinc by E. A. Owen and L. Pickup.
(Received 1937/07/26 Published 1937/10/20)
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