Magnesium-based medical device and manufacturing method thereof

Abstract

A magnesium-based medical device which can adjust a degree of corrosion within a wide range of period such that the device can maintain a sufficient strength only during a desired period and disappears within a desired period thereafter and a manufacturing method thereof are provided. A magnesium-based medical device of the present invention is a magnesium-based medical device in which a base material is made of magnesium or a magnesium alloy, wherein a corrosion-resistant film is formed on a surface of the base material, and variation in surface hardness of the formed corrosion-resistant film in the in-plane direction is less than 21 in terms of a dispersion value of Vickers hardness.

1 - 9 . (canceled) 
   
   
       10 . A magnesium-based medical device which has a base material made of magnesium or a magnesium alloy and is dissolved and disappears in a living body, wherein a corrosion-resistant film is formed on a surface of the base material, and variation in a numerical value of hardness of the formed film expressed in terms of Vickers hardness is controlled corresponding to desired corrosion resistance. 
   
   
       11 . A magnesium-based medical device according to  claim 10 , wherein the corrosion-resistant film contains calcium phosphate. 
   
   
       12 . A manufacturing method of the magnesium-based medical device according to  claim 10 , being characterized in that, in a state that the base material is immersed in a solution in which components for forming the corrosion-resistant film are dissolved, a flow of the solution whose flow speed is controlled is generated relative to the surface of the base material thus depositing a corrosion-resistant film on the surface of the base material. 
   
   
       13 . The manufacturing method of the magnesium-based medical device according to  claim 12 , wherein a degree of variation in a numerical value of hardness of the formed corrosion-resistant film which is expressed in terms of Vickers hardness in the in-plane direction is adjusted by controlling the flow speed of the solution relative to the surface of the base material. 
   
   
       14 . The manufacturing method of the magnesium-based medical device according to  claim 12 , wherein the base material is immersed in a solution which contains phosphorous ions and calcium ions thus forming the corrosion-resistant film containing calcium phosphate on the surface of the base material. 
   
   
       15 . A manufacturing method of the magnesium-based medical device according to  claim 11 , being characterized in that, in a state that the base material is immersed in a solution in which components for forming the corrosion-resistant film are dissolved, a flow of the solution whose flow speed is controlled is generated relative to the surface of the base material thus depositing a corrosion-resistant film on the surface of the base material. 
   
   
       16 . The manufacturing method of the magnesium-based medical device according to  claim 13 , wherein the base material is immersed in a solution which contains phosphorous ions and calcium ions thus forming the corrosion-resistant film containing calcium phosphate on the surface of the base material. 
   
   
       17 . The manufacturing method of the magnesium-based medical device according to  claim 15 , wherein the base material is immersed in a solution which contains phosphorous ions and calcium ions thus forming the corrosion-resistant film containing calcium phosphate on the surface of the base material.