Abstract The invention is directed to the production of non-fragile shaped members from powders comprising spheroidal metal particles. For this purpose, the invention provides a process for the production of shaped parts from powders comprising spheroidal metal particles which are mixed with from 0.2% to 2% of lubricant, comprising the combination of the following successive steps, performed in the below-indicated order: (a) mixing the powder formed by spheroidal metal particles with an amount of water-soluble cellulose gum between 0.2% and 2%, and with an amount of water which is also between 0.2% and 2%; (b) a cold compacting operation; (c) an optional oven drying operation; (d) a two-phase sintering operation, in an atmosphere which is neutral or reducing with respect to the compacted powder, the first phase being effected at a temperature of from 300° to 500° C. and the second phase being effected at a temperature which is substantially higher and variable with the nature of the powder.
A process for the production of shaped parts from a powder comprising spheroidal metal particles, comprising the successive steps of (a) mixing said powder with from 0.2% to 2% of lubricant of stearate type; (b) mixing said powder and said lubricant with from 0.2% to 2% of organic binder of cellulose gum type; (c) mixing the powder thus obtained with an amount of water of from 0.2% to 2%; (d) cold compacting the resulting mixture; and (e) subjecting said mixture to a two-phase sintering operation, in an atmosphere which is neutral or reducing with respect to said mixture, the first phase being effected at a temperature of from 300° to 500° C. and the second phase being effected at a temperature which is substantially higher.
Claim 2
Dependent Claim
125 words
A process for the production of shaped parts from a powder comprising spheroidal metal particles, comprising the successive steps of (a) mixing said powder with from 0.2% to 2% of lubricant of stearate type; (b) mixing said powder and said lubricant with from 0.2% to 2% of organic binder of cellulose gum type; (c) mixing the powder thus obtained with an amount of water of from 0.2% to 2%; (d) cold compacting the resulting mixture; and (e) subjecting said mixture to a two-phase sintering operation, in an atmosphere which is neutral or reducing with respect to said mixture, the first phase being effected at a temperature of from 300° to 500° C. and the second phase being effected at a temperature which is substantially higher.
Claim 3
Dependent Claim
31 words
A process according to claim 1, wherein the cold compacting method is selected from the group of methods comprising unidirectional compacting in a die, isostatic compacting, compacting by rolling and extrusion.
Claim 4
Dependent Claim
28 words
A process according to claim 1 or 2, wherein the powder used, comprising spheroidal metal particles, is produced by atomization of liquid metal by means of gas jets.
Claim 5
Dependent Claim
14 words
A process according to claim 1 or 2, wherein said cellulose gum is methylcellulose.
Claim 6
Dependent Claim
19 words
A process according to claim 1 or 2, wherein, between cold compacting and sintering, said mixture is oven dried.