Cold sintering of β-tricalcium phosphate/bioactive glass composites

Reaching high densification upon sintering β-tricalcium phosphate (β-TCP) has always been challenging. Its combination with bioactive glass (BG) is a common strategy to increase its densification, but still highly limited due to phase transformation. Cold sintering process (CSP) has gained attention in the search for alternatives to traditional sintering (TS), but the number of bioceramics explored is still limited. Thus, the main goal of this work was to use S53P4 BG as a sintering agent of β-TCP in CSP. Pellets of β-TCP/S53P4 (0, 30, and 60 wt%) were consolidated by CSP at 200 °C while being pressed at 166 MPa and compared with pellets sintered by TS at 1200 °C. Whereas β-TCP pellets showed no densification by CSP, the addition of 30 and 60 wt% S53P4 led to a significative increase in their density, of 76 ± 4% and 85 ± 3%, equivalent to the pellets consolidated by TS. CSP pellets were consolidated without showing the crystallization of S53P4 and presented a highly densified microstructure. Both CSP and TS pellets showed apatite formation in simulated body fluid (SBF) after 7 and 14 days. Thus, CSP has shown to be a promising alternative to TS when consolidating β-TCP/S53P4.