Statistical modelling of mechanical properties and bio-corrosion behaviour of Mg3Zn1Ca15Nb fabricated using microwave sintering

Abstract

Abstract In the present work, an optimum set of microwave sintering parameters was used to fabricate a newly developed biomaterial, namely Mg3Zn1Ca15Nb, with improved mechanical and bio-corrosion properties. In the recent work by authors, sintering parameters were optimized using the conventional sintering route (R1) to sinter Mg3Zn1Ca15Nb, which resulted in improved mechanical and degradation properties. Subsequently, to achieve better properties of Mg3Zn1Ca15Nb over R1, a microwave sintering route (R2) was used to sinter the same material at similar parameters, which were used in R1. However, the obtained properties of magnesium alloy matrix composite (MgMCs) sintered using R2 were found to be lower than the R1. This article was aimed to optimize the sintering parameters by microwave sintering route (R3) to get significant results over R1. Sintering parameters such as heating rate, sintering temperature, and holding time were taken for optimization. Also, the influence of sintering parameters on the mechanical and bio-corrosion properties of MgMCs was studied. Experimentations were proceeded according to central composite design (CCD). The mechanical and bio-corrosion properties of Mg3Zn1Ca15Nb, sintered using R3 was better than the R2. However, these properties were still behind the properties of the sample sintered using R1. Scanning electron microscopy (SEM) images of the sample showed clustering of powders and micro-cracks on the surface of the sample sintered using R2. However, by increasing the heating rate, a reduction in powder clustering and micro-cracks were observed. Additionally, the microscopic image showed a reduction in the size of porosity with an increase in heating rate. No phase formation was observed in the microwave sintered samples as per X-ray diffraction (XRD) analysis. In addition to this, the hydrophilic nature of Mg3Zn1Ca15Nb showed a good agreement for cell adhesion. Subsequently, the bio-corrosion behaviour of fabricated samples was tested in simulated body fluid (SBF) containing pH 7.4\xa0at 37 ± 0.5\xa0°C. The obtained corrosion rate of sample sintered using R3 was less than R2, whereas it was still higher than R1.