Electrolytic methods for production of high density copper powder

Claim 1

A method of producing copper powder of relatively high apparent density comprising the steps of: a. providing a copper powder cathode in which the copper powder has an apparent density from about 0.5 to about 4.0 g/cc; and a metal anode in an electrolytic composition comprising an aqueous solution of copper sulfate and sulfuric acid; b. imposing direct electrical current on the electrolytic composition so as to effect electrodeposition of copper from the from the electrolytic composition onto the copper powder cathode, the electrical current being of a current density such that no hydrogen gas is evolved; c. periodically interrupting the flow of direct electrical current, the ratio of the period of direct current flow to the period of interruption being from about 95:5 to about 55:45; d. agitating the copper powder cathode during electrodeposition; and e. continuing the electrodeposition of copper onto the copper powder cathode until copper powder having a desired apparent density in the range of from about 2.5 to about 5.0 g/cc and which is greater than the apparent density of the starting copper powder of the copper powder cathode is formed.

Claim 2

A method of producing copper powder of relatively high apparent density comprising the steps of: a. providing a copper powder cathode in which the copper powder has an apparent density from about 0.5 to about 4.0 g/cc; and a metal anode in an electrolytic composition comprising an aqueous solution of copper sulfate and sulfuric acid; b. imposing direct electrical current on the electrolytic composition so as to effect electrodeposition of copper from the from the electrolytic composition onto the copper powder cathode, the electrical current being of a current density such that no hydrogen gas is evolved; c. periodically interrupting the flow of direct electrical current, the ratio of the period of direct current flow to the period of interruption being from about 95:5 to about 55:45; d. agitating the copper powder cathode during electrodeposition; and e. continuing the electrodeposition of copper onto the copper powder cathode until copper powder having a desired apparent density in the range of from about 2.5 to about 5.0 g/cc and which is greater than the apparent density of the starting copper powder of the copper powder cathode is formed.

Claim 9

A method of producing copper powder of relatively high apparent density comprising the steps of: a. providing a metal anode and a metal cathode in a first electrolytic composition containing copper ions; b. electrodepositing copper from the electrolytic composition onto the metal cathode to form copper powder having a relatively low apparent density of less than about 3.0 g/cc; c. freeing the copper powder from the metal cathode; d. placing the copper powder in a second electrolytic composition containing copper ions and in which there is provided a metal anode; e. electrodepositing copper from the second electrolytic composition onto the copper powder having a relatively low apparent density of less than about 3.0 g/cc; and f. continuing the electrodeposition of step (e) until copper powder having an apparent density of at least 3.0 g/cc is formed.

Claim 10

A method of producing copper powder of relatively high apparent density comprising the steps of: a. providing a metal anode and a metal cathode in a first electrolytic composition containing copper ions; b. electrodepositing copper from the electrolytic composition onto the metal cathode to form copper powder having a relatively low apparent density of less than about 3.0 g/cc; c. freeing the copper powder from the metal cathode; d. placing the copper powder in a second electrolytic composition containing copper ions and in which there is provided a metal anode; e. electrodepositing copper from the second electrolytic composition onto the copper powder having a relatively low apparent density of less than about 3.0 g/cc; and f. continuing the electrodeposition of step (e) until copper powder having an apparent density of at least 3.0 g/cc is formed.

Claim 18

A method of producing copper powder of relatively high apparent density comprising the steps of: a. providing a solid metal anode and a solid metal cathode in an electrolytic composition comprising an aqueous solution of copper sulfate and sulfuric acid; b. imposing direct electrical current on the electrolytic composition of a current density such that hydrogen gas is evolved so as to effect electrodeposition of copper from the electrolytic composition onto the solid metal cathode to form copper powder on the cathode; c. periodically interrupting the flow of direct electrical current by imposing alternating current on the electrolytic composition, the ratio of the period of direct current flow to the period of alternating current flow being from about 95:5 to about 55:45; d. continuing the electrodeposition of copper from the electrolytic composition onto the solid metal cathode to form copper powder having an apparent density of from about 0.5 to about 4.0 g/cc on the cathode by reducing the current density of the imposed direct electrical current to a current density such that no hydrogen gas is evolved; e. periodically interrupting the flow of direct electrical current of reduced current density by imposing alternating current on the electrolytic composition, the ratio of the period of direct current flow to the period of alternating current flow being from about 95:5 to about 55:45; f. freeing the copper powder formed during steps (b) and (d) from the solid metal cathode and placing the copper powder as a cathode in an electrolytic composition of the same composition as that provided in step (a); g. providing a metal anode in the electrolytic composition with the copper powder cathode; h. imposing direct electrical current on the electrolytic composition so as to effect electrodeposition of copper from the electrolytic composition onto the copper powder cathode, the electrical current being of a current density such that no hydrogen gas is evolved; i. periodically interrupting the flow of direct electrical current by imposing reverse direct electrical current on the electrolytic composition, the ratio of the period of direct current flow to the period of reverse direct current flow being from about 95:5 to about 55:45; j. agitating the copper powder cathode during electrodeposition; and k. continuing the electrodeposition of copper onto the copper powder cathode until copper powder having a desired apparent density in the range of from about 2.5 to about 5.0 g/cc and which is greater than the apparent density of the copper powder of the copper powder cathode is formed.

Claim 19

A method of producing copper powder of relatively high apparent density comprising the steps of: a. providing a solid metal anode and a solid metal cathode in an electrolytic composition comprising an aqueous solution of copper sulfate and sulfuric acid; b. imposing direct electrical current on the electrolytic composition of a current density such that hydrogen gas is evolved so as to effect electrodeposition of copper from the electrolytic composition onto the solid metal cathode to form copper powder on the cathode; c. periodically interrupting the flow of direct electrical current by imposing alternating current on the electrolytic composition, the ratio of the period of direct current flow to the period of alternating current flow being from about 95:5 to about 55:45; d. continuing the electrodeposition of copper from the electrolytic composition onto the solid metal cathode to form copper powder having an apparent density of from about 0.5 to about 4.0 g/cc on the cathode by reducing the current density of the imposed direct electrical current to a current density such that no hydrogen gas is evolved; e. periodically interrupting the flow of direct electrical current of reduced current density by imposing alternating current on the electrolytic composition, the ratio of the period of direct current flow to the period of alternating current flow being from about 95:5 to about 55:45; f. freeing the copper powder formed during steps (b) and (d) from the solid metal cathode and placing the copper powder as a cathode in an electrolytic composition of the same composition as that provided in step (a); g. providing a metal anode in the electrolytic composition with the copper powder cathode; h. imposing direct electrical current on the electrolytic composition so as to effect electrodeposition of copper from the electrolytic composition onto the copper powder cathode, the electrical current being of a current density such that no hydrogen gas is evolved; i. periodically interrupting the flow of direct electrical current by imposing reverse direct electrical current on the electrolytic composition, the ratio of the period of direct current flow to the period of reverse direct current flow being from about 95:5 to about 55:45; j. agitating the copper powder cathode during electrodeposition; and k. continuing the electrodeposition of copper onto the copper powder cathode until copper powder having a desired apparent density in the range of from about 2.5 to about 5.0 g/cc and which is greater than the apparent density of the copper powder of the copper powder cathode is formed.