Sherritt Gordon Mines Limited

Maurice A Clegg

Michael J Ruscoe

Kshitindra M Sarkar

Ronald L Prowse

Arthur G McMullen

Willie H Seibt

Robert W Fraser

Andrew G Wysiekierski

A process for producing an Sm.sub.2 Co.sub.17 alloy suitable for use as a permanent magnet, the alloy also containing iron, copper and zirconium or a similar group IVB or VB transition metal, and optionally praseodymium in partial replacement of the samarium. The process comprises providing the alloy in a preliminary form, sintering the alloy at an elevated temperature to achieve a high density and high remanence, selecting a solution heat treatment temperature which is marginally below the solid+liquid/solid phase transformation temperature of said alloy, cooling the sintered alloy body from the sintering temperature to the solution treatment temperature in a controlled manner to put the alloy constituents into a substantially uniform 2-17 Sm-Co solid solution, holding at the solid solution treatment temperature, quenching the alloy to room temperature, reheating the alloy to a first aging temperature to transform the 2-17 Sm-Co solid solution into a structure comprising a network of the 1-5 Sm-Co phase within a 2-17 Sm-Co matrix, cooling the alloy to a second aging temperature in a controlled manner to cause regions of 2-17 Sm-Co phase to nucleate coherently within the 1-5 Sm-Co phase network and create lattice strain which results in high coercivity and good loop squareness, and cooling the alloy to room temperature.

Process for producing Sm.sub.2 Co.sub.17 alloy suitable for use as

A process for producing cobalt-rare earth alloy powders suitable for forming into permanent magnets includes mixing cobalt powder particles having refractory oxide dispersoid powder particles fixed in the surfaces of the cobalt particles with particles of a rare earth element in a proportion corresponding to the composition of the alloy to be formed. The mixture is heated to cause the cobalt-dispersoid particles and the rare earth particles to form the desired alloy by diffusion with substantially no sintering.

Process for the production of cobalt-rare earth alloy powders

A blank suitable for minting to form a coin or similarly disc-shaped article has an appropriately disc-shaped steel core completely encased by a copper coating electroplated thereof. The blank is produced by electroplating a copper coating onto an appropriately disc-shaped steel core such that the copper coating completely encases the steel core.

Coins and similarly disc-shaped articles

Method of forming blanks for coins

A process for the production of coin blanks suitable for minting into coins, includes providing metal coin core pieces of disc-like shape each having opposed faces from about 14 mm to about 40 mm in diameter and a face to face thickness of from about 0.5 mm to about 2.6 mm. A charge of core pieces is loaded into a non-conducting perforated container with a diameter of from about 15 cm to about 50 cm, the number of core pieces in the container being such that the core pieces occupy from about 1/4 to 1/2 of the container volume. The container is placed in an electroplating bath, and a metallic cladding is plated on the core pieces, while moving the container angularly about a horizontal axis, at a voltage of from about 6 volts to about 18 volts and a current density of from about 470 A/m.sup.2 to about 1400 A/m.sup.2 based on the exposed area of the charge, until a plating thickness of from about 0.03 mm to about 0.08 mm of metal has been deposited on each face of each core pieces and a thickness of from about 2 to about 4 times the face thickness has been deposited on the circumference of each core piece. The cladded core pieces are then removed from the container and heated to form a metallurgical bond between the metallic cladding and core piece of each cladded core piece and to reduce the hardness to less than 65 on the Rockwell 30T hardness scale.

Process for the production of coin blanks

A process for the production of coin blanks suitable for minting into coins includes providing metallic core pieces, each core piece having opposed, substantially planar faces and a common side edge. The core pieces are loaded into a perforated container which is placed in an electroplating bath. A metallic cladding is placed on the core pieces, while moving the container angularly about a horizontal axis, until the metallic cladding has a thickness of at least about 0.05 mm on each face of each core piece and a thickness of at least 2 to 4 times the face thickness on the side edge of each core.

Process for the production of nickel clad steel coinage blank

A two-component blank suitable for minting into a coin is described. The blank consists of a low-carbon steel core completely encased in nickel. The blank has magnetic properties sufficiently similar to a solid nickel coin of the same size that the minted blank is accepted by magnetic property testing coin discriminating devices which accept pure nickel coins.

Growing community of inventors

Fort, Canada

Maurice A Clegg