Porous Metal Articles Having A Predetermined Pore Character

Abstract

A porous metal article having a predetermined pore structure. The porosity is provided by the use of an extractable particulate in a powder forming route to create a desired porosity. Extraction of the pore forming particulate prior to sintering of the powder minimizes contamination of the sintered article and allows for the processing of material sensitive to contamination such as titanium. Added functionality can be gained by co-forming the porous material with non-porous material to create an article with layers of differing characteristics. The article is suitable for use as an implant body is porous enough to facilitate tissue in-growth and bony fusion.

1 . A porous biocompatible metal article comprising:
 a metal matrix comprising a first sintered powder metal,   pores formed by an extractable material in the metal matrix wherein the extractable material is removed prior to sintering the first powder metal, and   a metal substrate bonded to the metal matrix.   
   
   
       2 . The porous metal article of  claim 1 , wherein the metal article is an orthopedic implant. 
   
   
       3 . The metal article of  claim 1 , wherein the first powder metal comprises one of titanium, tantalum, cobalt chromium, niobium, and stainless steel. 
   
   
       4 . The metal article of  claim 1 , wherein the pores are between about 50% and about 90% of the metal matrix by volume. 
   
   
       5 . The metal article of  claim 1 , wherein the extractable material is water soluble. 
   
   
       6 . The metal article of  claim 1 , wherein the extractable material comprises one of potassium chloride, sodium chloride, and potassium sorbate. 
   
   
       7 . The metal article of  claim 1 , wherein the extractable material provides a pore character in the metal matrix. 
   
   
       8 . The metal article of  claim 7 , wherein the pore character includes one of pore density, pore size, pore size dimension, and pore distribution. 
   
   
       9 . The metal article of  claim 1 , wherein the metal substrate comprises a second sintered powder metal. 
   
   
       10 . The metal article of  claim 9 , wherein the first powder metal and the second powder metal are sintered simultaneously. 
   
   
       11 . The metal article of  claim 1 , wherein the metal substrate is substantially dense prior to sintering the first powder metal. 
   
   
       12 . The metal article of  claim 1 , wherein the metal substrate is bonded by one of a diffusion bond or a sinter bond. 
   
   
       13 . A porous biocompatible metal article comprising:
 a sintered metal matrix having a tailored pore character, and   a metal substrate bonded to the metal matrix,   the metal matrix having been formed from a mixture of a liquid extractable pore former and a first metal powder.   
   
   
       14 . The metal article of  claim 13 , wherein the tailored pore character is formed by the extractable pore former prior to sintering the first powder metal. 
   
   
       15 . The metal article of  claim 14 , wherein the extractable pore former is removed prior to sintering of the first metal powder. 
   
   
       16 . The metal article of  claim 13 , wherein the pore character includes one of pore density, pore size, pore dimension, and pore size distribution. 
   
   
       17 . The metal article of  claim 13 , wherein the metal substrate comprises a second sintered powder metal. 
   
   
       18 . The metal article of  claim 17 , wherein the first powder metal and the second powder metal are sintered simultaneously. 
   
   
       19 . The metal article of  claim 13 , wherein the metal substrate is substantially dense prior to sintering the first powder metal. 
   
   
       20 . The metal article of  claim 13 , wherein the metal substrate is bonded by one of a diffusion bond or a sinter bond.