Method for producing a medical implant from a magnesium alloy

A method for producing a medical implant, such as a bone screw, a bone nail, a bone pin, a plate, or a suture anchor for attaching soft tissues, such as tendons, muscles and ligaments, to a bone, or in the form of an endoprosthesis or at least a part thereof, from a magnesium alloy comprising a magnesium content of at least 80% by weight, a rare earth metal content from 2.5 to 5% by weight, an yttrium content from 1.5 to 5% by weight, a zirconium content from 0.1 to 2.5% by weight by weight, a zinc content from 0.01 to 0.8% by weight and unavoidable impurities, wherein the total content of possible impurities is less than 1% by weight and the aluminium content is smaller than 0.5% by weight, and the remainder contains magnesium up to 100% by weight, comprising the following steps:

• a) melting the alloy components at 700 to 900° C. and then mixing them thoroughly to obtain a magnesium alloy, and pouring the magnesium alloy into moulds at a temperature of 700 to 900° C.,
• b) melting the magnesium alloy to obtain an alloy melt,
• c) atomising the alloy melt at a temperature from 775 to 850° C. and under a pressure from 17 to 23 bar in a protective gas atmosphere, and at the same time cooling the atomised alloy melt to below its solidification point to obtain an alloy powder,
• d) shaping the alloy powder by compaction under cold istostatic conditions for obtain an alloy green body with at least 100 bar,
• e) extruding the alloy green body to obtain a magnesium alloy moulded part, wherein the alloy green body is heated to a temperature from 300 to 400° C. before extrusion, and
• f) producting the medical implant from the magnesium alloy moulded part.