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For the purpose of modelling powder compaction, a quantitative evaluation of the friction conditions at the die wall interface is required. Using an instrumented compaction die, the friction at the interface between powder compact and die wall was evaluated through an empirical parameter called the slide coefficient, obtained from the applied pressure/transmitted pressure ratio. For powder compaction modelling, knowledge of the friction coefficient at the interface, however, is much more useful but its measurement is difficult in real experimental conditions. A procedure based on the evaluation of the radial stress/axial stress ratio leads to the quantitative determination of the friction coefficient in admixed zinc stearate added to iron powder with and without die wall lubrication. The resulting decreasing friction coefficient at the end of compaction gives a more uniform density characterised by low loss of pressure 1 Variables associated with single action pressing from through the compact and lower ejection energy per upper punch: angle w characterises radial stress/axial unit volume of the compact.PM/0826 stress ratio Professor Turenne and Ms Gode `re are in the De ´partement de ge ´nie physique et de ge ´nie des mate ´r-and ejection of the green part from the die but are difficult to remove during sintering. Moreover, the importance of iaux, E ´cole Polytechnique de Montre ´al, C.P. 6079, Succ. Centre-Ville, Montre ´al, PQ, H3C 3A7, Canada, the influence of lubricant content in powder mixes on mechanical properties of green and sintered parts is and Dr Thomas and Mr Mongeon are at the Industrial Materials Institute, National Research recognised.3 Some technical approaches have been published to suggest die wall lubrication but the economic Council

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Three similar varieties of pure Ti hydride-dehydried (HDH) powders were tested for the understanding of the variables that have an influence on the compaction process of Ti powders. The study shows that small differences in the characteristics of the powders lead to very different behaviours in the compaction stage. Compressibility curves, friction with the die walls and ejection forces are discussed in this study. The results are compared with a commercial iron powder as a reference to complete the discussion, as well as to show the enhancements and modifications that should be performed in Ti powders to design an optimized powder suitable for being pressed in an industrial process.

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/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur.Applied Spectroscopy, 50, 6, pp. 774-780, 1996 New approach to quantitative analysis of two-component polymer systems by infrared spectroscopy Cole, K. C.; Thomas, Y.; Pellerin, E.; Dumoulin, M. M.; Paroli, R. M. January 1996A version of this document is published in / Une version de ce document se trouve dans:Applied Spectroscopy, 50, (6), pp. 774-780, 1996 The material in this document is covered by the provisions of the Copyright Act, by Canadian laws, policies, regulations and international agreements. Such provisions serve to identify the information source and, in specific instances, to prohibit reproduction of materials without written permission. For more information visit http://laws.justice.gc.ca/en/showtdm/cs/C-42Les renseignements dans ce document sont protégés par la Loi sur le droit d'auteur, par les lois, les politiques et les règlements du Canada et des accords internationaux. Ces dispositions permettent d'identifier la source de l'information et, dans certains cas, d'interdire la copie de documents sans permission écrite. Pour obtenir de plus amples renseignements : http://lois.justice.gc.ca/fr/showtdm/cs/C-42 A new treatment is proposed for quantitative analysis of two-component polymer systems by infrared spectroscopy. Like much previous work, it is based on a ratio involving two peaks in the same spectrum. The relationship between such a ratio and the concentration of a given polymer is inherently nonlinear. It is shown that this nonlinearity can be well described by a simple equation derived from the laws of optical transmission. This equation has the form Xl = m 1 + mzR/(l + ｭ ｾ Ｉ where Xl is the weight fraction of polymer 1, the m i are adjustable coefficients, and the ratio R is equal to Aj(A u + A b ). The quantities An and A b are the absorbances (peak heights or areas) at two frequencies a and b of which the first is associated mainly with polymer 1 and the second with polymer 2. This equation has been applied to various peak combinations in spectra of miscible blends of poly(phenylene ether) with polystyrene (both mid-IR and near-IR data) and immiscible blends. of polypropylene with polyethylene (mid-IR data). It is shown that the equation is valid in all cases, covering the full concentration range from 0 to 100% even when the peaks used for the analysis involve absorption by both polymers. It is therefore believed to be of broad general usefulness for the analysis of polymer blends and copoly...