and kinetic energy: metal mass flow rate ratio. Both these describe operating attributes of the nozzle hut it is not known which offers the more universal figure of merit. Data from a range of studies were assembled in an attempt to determine the most effective figure of merit.
PMzTECZOOI.The Abstracts which follow are of papers presented at the ZOOI international
Conference on Powder
Metallurgy and Particulate Materials, which was held in New Orleans, USA, in May.
The role of energy in gas atomisation
Effect of aspiration base pressure on melt atomisation J.Ting et al. (Crucible Research Inc., USA.)
Atomization was discussed with regard to the parameters which require control in order to produce fine powders. Gasonly aspiration press sure was shown only to allow evaluation of atomization stability. and does not indicate effects on metal flow rate or particie refinement. Theory linking aspiration, atomization and particle refinement was discussed. Atomizer experiments were described. Particle size refinement and melt flow were discussed with respect to aspiration characteristics and nozzle shape.
J.T.Stmuss.
Enhancing green strength of PM materials L Trembiay, F.Chqnon.
(Quebec Metal Powders Ltd. /
Canada, j
Atomisation
Quantification efficiency
strong molecular interaction, was demonstrated by use of Fourier transform infrared spectroscopy.
J.JBunkley. (Atomking
of atomisation
fHJE Cmqmny, Inc., USA.)
Gas atomization nozzle efficiency was discussed with reference to gas:metal flow ratio
SLOT
Systems Ltd.,
UK.)
Using published data parameters affecting particle size in gas atomisation were discussed in order to establish the value of an energy term. Thermal energy for rhe process derives from gas and metal and their relative contributions and a volume ratio of gas: metal were discussed. Existing correlations were discussed and possible new correlations were proposed.
Lubricants mixed with PM feedstocks were reviewed with respect to the effects of additives on green properties, cracking and development of improved lubricants. Green and sintered properties of FC-0205, with green strength enhancing lubricants were investigated for sampIes processed to densities 6.8, 7.0 and 7.2 gm.cm-3 and compared with samples made with EBS waxes. Machining in the green state was discussed. It was reported that the new lubricants doubled the green strength.
Interaction of graphite with lubricants
Lubrication Complex polymeric binder-lubricant blends
D.Derwin, K.H.Moyer.
(Magna-Tech PM Labs., USA.)
The role of graphite in ferrous PM was discussed. It was noted that while lubricants are L.Tremblay et al. (Quebec Metal Powders Ltd., Canada,) being improved graphite is ‘taken for granted’. Lubricants, used in PM to lower die wall fries Interactions between grades of graphite and tion, were discussed and the reduction in green lubricants were studied for influence of a range strength and the need for improved lubricants of different graphite-lubricant combinations were noted. A new concept, in which a polymeron powder and compact green properties including effects in storage. Stability in storage ic hinder is blended with a lubricant, was prewas correlated with environmental conditions. between these, due to sented. Complexing
HEATER
Ultrafine, clean metal powders for: l l l
MIM magnetic alloys hydrogen storage
l l l
l l l
RSP Properties thick film pastes plasmalHVOF
R&D facility trial batches alloy design
l l l
l l l
low oxygen metal matrix dental alloys
Melt spinners CWCVD systems Arc melters
“22
Warm compaction” offers an increase
in green density and strengfh. Capacities:
the powder and can be
Phoenix Saentlfic industries Ltd Apex Business Park, Hallsham, East Sussex BN27 3JU. UK Tel: (01323) 449001; Fax: (01323) 449002
New Reader
Enquiry
Go to www.metal-powdersnet
Service No 612. to make your enquiry.
New Reader Enquiry Go to www.metal-powder.net
Service No 613. to make your enquiry.