Principal Investigator:  John Moore

Partners:  Guigné International, Ltd., BioServe Space Technologies, Hewlett-Packard

Description:  Porous ceramics, glass-ceramics and composites are synthesized from starting powders using a process known as self-propagating high-temperature synthesis, or SHS.  In this process, the initial constituents undergo exothermic reactions, wherein the heat released is greater than that required to sustain the reaction in the material, resulting in a self-propagating reaction that, under the right conditions, proceeds to completion throughout the "green" pellet.  The final product is usually quite porous.  The total porosity, pore size distribution and ratio of open to closed porous is controlled by the experimental parameters.  One important experimental parameter has been found to be gravity.  In experiments done by CCACS researchers, dramatic differences have been observed in the properties of materials prepared in normal gravity (1g) and the near-zero gravity obtainable in NASA's parabolic-flight aircraft.  The materials are very light in weight and can be made strong enough for many bone-replacement applications.  It has been found that the pore properties can be tailored to match those of natural bone, making the growth of the natural bone into the implants much more likely than is the case with conventional implants.

Markets:  The markets for these materials are through the pharmaceutical companies specializing in bone repair in cranio-facial, limb and hip areas and are in the billions of dollars.  The materials in use today all have problems associated with them. For example, the most commonly used material, hydroxyapatite (Ca3PO4), costs about $10 per gram but is incompatible with bone growth in many applications.  Another material that is sometimes used, cadaver bone powder, costs $30 per gram and has been known to carry pathogens.  Recently developed materials derived from sea coral have shown promise, but lack the strength necessary in many applications.

Project Status and Plans:  Microgravity experiments have been done for several years in NASA's KC-135 and are planned for the International Space Station (ISS).  The revolutionary Space-DRUMS™ containerless processing facility will be installed on ISS in January, 2004.  After that, routine microgravity measurements will be possible for extended periods of time.  It will be possible to adjust the experimental parameters for optimal processing of porous materials with prescribed properties.  Knowledge gained from these experiments will be brought back to earth for incorporation into more cost-effective processes.

To Get Involved:  Interested companies may join CCACS now for a nominal fee to participate in these experiments.  Intellectual property rights to commercial applications are protected.
 
 

Low Gravity                                                                                         Normal Gravity