National Research Council of Canada

The Royal Institution for the Advancement of Learning / Mcgill University

Louis-Philippe Lefebvre

Yannig Thomas

Sylvain Pelletier

Edward J Harvey

Paul A Martineau

Eric Irissou

Blaise Champagne

Claude Gelinas

Maxime Gauthier

A new spray process allows for deposition below a critical velocity limit of cold spray, while providing adhesion. Post deposition heat treatment has shown excellent coating strength. A wide variety of materials can be deposited. The spray process is based on ShockWave Induced Spraying (SWIS) but with much slower spray jet projection velocities. High porosity, pore size control, and porosity control are demonstrated to be controllable. Preheating of feedstock and uniform temperature of the SWIS delivery allow for the deposition below critical velocity.

Porous metal coatings using shockwave induced spraying

A bone screw and method of producing the same is described. The method of producing a bone screw includes forming a one-piece headless screw body out of a rigid metallic foam that is entirely porous throughout and defines a plurality of inter-connected pores having a size of about 30 to about 500 microns in diameter. The method includes providing at least one thread on an external surface of the screw body, and forming a bore extending through an entire axial length of the screw body, the bore forming a cannula that defines an annular radial wall thickness of the screw body. The method further includes disposing the inter-connected pores throughout the radial wall thickness of the screw body such as to allow for bone in-growth through the full radial wall thickness and into the cannula.

Method of producing a porous bone screw

A bone screw is described which includes a one-piece threaded screw body composed at least partially of a rigid foam. The screw body is headless and includes a bore extending therethrough to define a cannula and thereby providing the screw body with an annular shape defining a radial wall thickness. At least a central portion of the screw body is formed of the rigid foam which defines a matrix having a plurality of inter-connected pores therein. The inter-connected pores are disposed throughout the complete radial wall thickness of the screw body from an outer surface of the screw body to an inner surface thereof within the cannula, such as to permit bone in-growth through the complete radial wall thickness of the annular screw body. The inter-connected pores and the cannula thereby respectively allow bone in-growth through the complete radial wall thickness and the full axial length of the screw body.

Porous bone screw

The porous material of the present invention is produced by heating a dry powder mixture, containing mainly an organic solid binder and inorganic particles. The mixture is foamed while the organic binder is melted. Foaming comes from a foaming agent in the powder mixture. The solid foamed structure comprising inorganic particles embedded in an organic binder is then heated to eliminate the organic binder and finally to sinter the remaining inorganic tri-dimensional network into a rigid structure having interconnected porosity.

Method of making open cell material

Near-net-shape soft magnetic components can be produced from iron powder-lubricant compositions using powder metallurgy techniques. The resulting components have isotropic magnetic and thermal properties and may be shaped into complex geometry using conventional compaction techniques. A non-coated ferromagnetic powder is mixed with a lubricant and compacted. After compaction, the components are thermally treated at a moderate temperature to burn out the lubricant, and possibly also relieve the stresses induced during pressing and reduce the hysteresis losses. Depending on the application, the properties of the material may be tailored by varying the content and type of the lubricant and the thermal treatment conditions.

Manufacturing soft magnetic components using a ferrous powder and a lubricant

Near-net-shape soft magnetic components can be produced from iron powder lubricant compositions using powder metallurgy techniques. The resulting components have isotropic magnetic and thermal properties and may be shaped into complex geometry using conventional compaction techniques. A non-coated ferromagnetic powder is mixed with a lubricant and compacted. After compaction, the components are thermally treated at a moderate temperature to burn out the lubricant, relieve the stresses induced during pressing and reduce the hysteresis losses. Depending on the application, the properties of the material may be tailored by varying the content and type of the lubricant and the thermal treatment conditions.

Post-compaction treatments of iron compacts to improve the mechanical strength of the compacts are provided. Powder is compacted into the desired part. The part is then subjected to a strengthening operation. This operation involves a heat treatment at a moderate temperature combined with an optional resin impregnation. The heat treatment is done at a temperature sufficient to increase the mechanical properties of the compact while maintaining the magnetic losses low for the required application. Impregnation with an insulating binder can be effected to increase the mechanical strength of the part without creating electric contacts between the powder particles.

Treatment of iron powder compacts, especially for magnetic applications

The present invention relates to particle agglomeration of aluminum powder using a lubricating binder. The resulting powder has improved flowability and can be shaped easily. The aluminum particles are admixed with a lubricant, e.g. polyethylene, and are held together by the lubricant. To agglomerate the aluminum powder, the lubricant is melted and is then solidified to form solid bridges between the aluminum powder particles. The lubricant may be burned out cleanly at temperatures lower than 450.degree. C.

Lubricated aluminum powder agglomerates having improved flowability

Aluminum powder compositions intended for powder metallurgy applications are provided. The powder compositions contain aluminum and aluminum alloys or blends made from elemental powders, admixed with a polyethylene lubricant. The polyethylene admixture eases the compaction of powders and the ejection of parts. As compared to other conventional admixed lubricants used for Al powder metallurgy applications, polyethylene allows to obtain parts with higher green and sintered strengths. Proper delubrication prior to sintering is of importance.

Lubricated aluminum powder compositions

A method for producing composite insulating coatings on powder particles, the coatings containing an electrically insulating metal compound and an organic polymer. The coatings are deposited preferably by controlled spraying, simultaneous or sequential, of sol precursors of insulating metal compounds and polymer emulsions or solutions onto polymer, metal or ceramic powder particles preferably during the blending or mixing of the particles. The process is useful for mass production of coated iron-based powders used for shaping components by powder metallurgy techniques for magnetic applications. Coated iron based powders can be cold or warm pressed and heat treated to obtain the desired mechanical properties.

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Montreal, Canada

Louis-Philippe Lefebvre