Biodegradable magnesium alloys, methods of manufacture thereof and articles comprising the same

1. A method comprising:

blending three or more metals to form a metal alloy, where the metal alloy comprises a base metal, a second element and a third element; where the base metal is magnesium, calcium, strontium, zinc, or a combination thereof; where the second element is chemically different from the third element; and where the second element and the third element are scandium, yttrium, gadolium, cerium, neodymium, dysporium, or a combination thereof;

molding the metal alloy; and

annealing the metal alloy at a temperature and in an atmosphere effective to produce a protective layer on the metal alloy; where the protective layer is reactively bonded to the metal alloy and where the protective layer is non-metallic, where the protective layer comprises a base non-metallic derivative, a second non-metallic derivative and a third non-metallic derivative of metals present in the metal alloy; and where the base non-metallic derivative, the second non-metallic derivative and the third non-metallic derivative are all chemically different from one another.

2. The method of claim 1 , where the metal alloy is annealed at a temperature of about 25 to about 800° C.

3. The method of claim 1 , where the atmosphere contains oxygen, carbon, boron, silicon, selenium, fluorine, bromine, iodine, tellurium, sulfur, nitrogen, or a combination thereof.

4. The method of claim 1 , where the metal alloy comprises a base metal, a second element and a third element; where the base metal is magnesium, calcium, strontium, zinc, or a combination thereof; where the second element is chemically different from the third element; and where the second element and the third element are scandium, gadolium, cerium, neodymium, dysporium, or a combination thereof; and

where the protective layer comprises a base non-metallic derivative, a second non-metallic derivative and a third non-metallic derivative of metals present in the metal alloy; and where the base non-metallic derivative, the second non-metallic derivative and the third non-metallic derivative are all chemically different from one another.

5. The method of claim 4 , where the protective layer comprises a plurality of layers; with an outermost layer comprising an oxide of magnesium, calcium, strontium, or a combination thereof; while an inner layer comprises an oxide of scandium, gadolium, cerium, neodymium, dysporium, or a combination thereof.

6. The method of claim 4 , where the protective layer has a thickness of 0.1 nanometers to 500 nanometers.

7. The method of claim 4 , wherein the base metal is magnesium.

8. The method of claim 4 , wherein the base metal is calcium.

9. The method of claim 4 , wherein the base metal is strontium.

10. The method of claim 4 , wherein the base metal is zinc.

11. The method of claim 4 , wherein the base metal is magnesium, the second element is scandium, and the third element is cerium.

12. The method of claim 1 , where the metal alloy comprises a base metal, a second element and a third element; where the base metal is calcium, strontium, zinc, or a combination thereof where the second element is chemically different from the third element; and where the second element and the third element are scandium, yttrium, gadolium, cerium, neodymium, dysporium, or a combination thereof; and

where the protective layer comprises a base non-metallic derivative, a second non-metallic derivative and a third non-metallic derivative of metals present in the metal alloy; and where the base non-metallic derivative, the second non-metallic derivative and the third non-metallic derivative are all chemically different from one another.

13. The method of claim 12 , where the protective layer comprises a plurality of layers; with an outermost layer comprising an oxide of calcium, strontium, or a combination thereof; while an inner layer comprises an oxide of scandium, yttrium, gadolium, cerium, neodymium, dysporium, or a combination thereof.

14. The method of claim 12 , wherein the second element is yttrium and the third element is scandium.

15. The method of claim 12 , wherein the second element is yttrium and the third element is selected from gadolium, cerium, neodymium, dysporium, or a combination thereof.

16. The method of claim 12 , wherein the second element is scandium and the third element is selected from gadolium, cerium, neodymium, dysporium, or a combination thereof.

17. The method of claim 1 , where the metal alloy comprises a base metal, a second element and a third element; where the base metal is magnesium, calcium, strontium, zinc, or a combination thereof where the second element is chemically different from the third element; and where the second element and the third element are gadolium, cerium, neodymium, dysporium, or a combination thereof;

where the protective layer comprises a base non-metallic derivative, a second non-metallic derivative and a third non-metallic derivative of metals present in the metal alloy; and where the base non-metallic derivative, the second non-metallic derivative and the third non-metallic derivative are all chemically different from one another; and

wherein the protective layer comprises a plurality of layers; with an outermost layer comprising an oxide of magnesium, calcium, strontium, or a combination thereof while an inner layer comprises an oxide of gadolium, cerium, neodymium, dysporium, or a combination thereof.

18. The method of claim 17 , wherein the outermost layer is an oxide of magnesium.

19. The method of claim 17 , wherein the outermost layer is an oxide of calcium.

20. The method of claim 17 , wherein the outermost layer is an oxide of strontium or an oxide of zinc.