Nanomaterial could guarantee body prostheses for more than 150 years
A Basque industrial engineer has developed and tested a new nanocompound which she claimed could be used to make body prostheses that will last more than 150 years.
The new material is made from carbon nanotubes coated with nanoparticles of zirconia. According to the engineer, Nere Garmendia, who has just published her PhD thesis on the topic, the use of nanoparticles avoids the ageing problems experienced in tests with micrometric zirconia (ZrO2, a ceramic).
The PhD thesis is titled Development of a new nanocompound material made of zirconia with coated carbon nanotubes, for orthopaedic applications, and Garmenia’s aim is to help develop body prostheses which will not need replacement every 10-15 years, as current ones do.
She reinforced the connection between the zirconia matrix and the nanotubes, with the intention of improving the transfer/distribution of loads, by coating the nanotubes with nanoparticles of zirconia and then heating the nanoparticles beyond their boiling point (hydrothermal synthesis). This coating functioned as a bridge between the zirconia matrix and the nanotubes.
According to Garmendia, who is a postgraduate student at the Department of Mining Engineering and Metallurgy and Materials Sciences of the Higher Technical School of Engineering in Bilbao, Spain, working at a nanometric scale is the key to a longer-lasting material. In a prior experiment with micrometric zirconia it was concluded that this material would end up considerably aged after 12 years.
Adding zirconia nanoparticles to the nanotubes facilitated the dispersion of the material, reduced its viscosity, and helped increase its density for the final stage of sintering, Garmendia said. Sintering is a process, used particularly in ceramics, that transforms the material from powder to a compact solid. In order to achieve the maximum possible density, it has to be decided before sintering how many nanotubes are to be introduced.
Garmendia said her calculations showed that, if the intention is to obtain the maximum possible density of 98 per cent, one per cent of the volume must be coated nanotubes. Finally, the material has to be sintered in argon for one hour at 1,300 degrees; not more nor less.