Microwave sintering of nano size powder β-TCP bioceramics

B Mirhadi

doi:10.2298/sos1402185m

Abstract

A nano sized beta tricalcium phosphate (?-TCP) powder was conventional sintered (CS) and microwave sintered (MW), in order to obtain dense ?-TCP ceramics. In this work the effect of microwave sintering conditions on the microstructure, phase composition and mechanical properties of materials based on tricalcium phosphate (TCP) was investigated by SEM (scanning electron microscopy)and XRD(X-ray diffraction) and then compared with conventional sintered samples. Nano-size ?-TCP powders with average grain size of 80 nm were prepared by the wet chemical precipitation method with calcium nitrate and diammonium hydrogen phosphate as calcium and phosphorus precursors, respectively. The precipitation process employed was also found to be suitable for the production of submicrometre ?-TCP powder in situ. The ?-TCP samples microwave (MW) sintered for 15 min at 1100?C, with average grain size of 3?m, showed better densification, higher density and certainly higher hardness than samples conventionally sintered for 2 h at the same temperature. By comparing sintered and MW sintered ?-TCP samples, it was concluded that MW sintered ?-TCP samples have superior mechanical properties.

Highlights

Bioceramic materials are widely used to repair and reconstruct damaged parts of the human skeleton
Calcium phosphate ceramics materials based on hydroxyapatite (HAP) and tricalcium phosphate (TCP), due to their chemical composition, excellent biocompatibility, bioactivity and osteoconduction have received considerable attention as suitable bioceramics for the manufacture of osseous implants [1,2,3,4,5,6].Dense forms of beta tricalcium phosphate with good mechanical properties are often used as reparation material in maxillofacial, dental and orthopaedic surgery [7]
The X-ray diffraction (XRD) patterns of the β-TCP samples microwave sintered (MW) sintered at 900 ̊C, 1000 ̊C and 1100 ̊C for 15 min, shown in fig. 7, exhibited just peaks of β-TCP crystalline phase

Summary

Introduction

Bioceramic materials are widely used to repair and reconstruct damaged parts of the human skeleton. Significant improvements have been made in increasing the fracture toughness of bioceramic materials through the control of density and microstructure, especially through the effect of grain size [7,8]. The decrease in grain size from the micro to the nano level gives the explanation for the increased fracture toughness of dense bioceramic materials[9]. Nanostructured bioceramics are usually processed by compacting nanopowders at high pressures and sintering at different times and temperatures and in various atmospheres. Pressure assisted methods, such as hot pressing, hot isostatic pressing, sinter forging, etc., are applied to obtain nanostructuredceramic materials [1011]

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