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Recently, zinc (Zn) is extensively observed as biomaterial or biodegradable implant for medical application. A biomaterial is any substance that has been engineered to interact with biological systems for a medical purpose. Zn is chosen because it has moderate degradation compared to Mg and Fe. Unfortunately, Zn has limitation on its mechanical properties that still low. The Alloying element is needed to improve the mechanical properties of Zn. Alloying element, such as zirconium (Zr) can improve the mechanical properties of Zn. In this study the addition of Zr with the composition variations of 0%, 0.5%, 1%, and 2% were used. Two kinds of alloying method used are centrifugal casting and box furnace with a temperature of 550°C. The aims of this study are to know the effect of each fabrication method to the mechanical properties and the result of Zn-Zr alloy microstructures. The results show that the microstructure of the alloy from centrifugal casting is more homogenous than the box furnace method. The mechanical properties of centrifugal casting are also higher than the box furnace method. The hardness value obtained from centrifugal casting of 0, 0.5, 1, 1.5 and 2% of Zr are 35.162 HV, 41.988 HV, 42.324 HV, 57.112 HV, respectively.

In this work, corrosion behaviour of zinc-based alloys with addition of 0.5%, 1%, and 2% of zirconium for biodegradable material as orthopaedic implant were investigated. The potentiodynamic polarization method is carried out to determine the corrosion resistance and corrosion rate of each composition in order to observe the effect of zirconium addition in a Kokubo simulated body fluid solution. The result showed that the addition of 0.5% and 1% of zirconium would decrease the corrosion rate of Zn-xZr alloys corresponding to 0.079 mm/year and 0.116 mm/year whereas the 2% addition would increase the rate to 0.188 mm/year due to the formation of Zr-rich precipitates inside the alloys. The passivation zone on the polarization curve showed the formation of the protected thin layer on the surface of the alloys which caused the corrosion rate to decrease, therefore confirmed the degradable ability of the Zn-xZr alloys. In general, the corrosion rates of Zn-xZr alloys were higher than Fe-based alloys and lower than Mg-based alloys. Moreover, the corrosion rates were much lower than the maximum rate of 0.4 mm/year for biodegradable implants so Zn-xZr alloys were suitable as biodegradable material implant for orthopaedic application.

The development of Mg and Fe based biomaterials in the past decade has been extensively studied as biodegradable material for medical applications. The development of this material is limited in terms of its suitability for clinical applications. Zn-based alloys began to be an alternative to be studied as a substitute for Mg and Fe based biomaterials. Zn-based alloys have a moderate degradation rate but have low mechanical properties, so other elements need to be added to improve their mechanical properties. In this study, the added element is zirconium (Zr) with a composition variation of 0.5%, 1%, and 2%. The alloying method used was casting with a temperature of 550°C. The results of the microstructure analysis, the addition of Zr to Zn alloys will form precipitates in the side of the grain boundaries and more addition of Zr composition, the smaller grain size formed. The grain size from pure Zn until the addition of 2% Zr in the sequence are 266.40 µm, 20.16 µm, 16.70 µm, and 15.85 µm. The XRD analysis, from the addition of Zr, will form the Zn phase and the intermetallic phase Zn22 Zr. The hardness value obtained from pure Zn until 2% Zr in the sequence are 35.162 HV, 41.988 HV, 42.324 HV, 57.112 HV.

Severe burns need additional collagen to accelerate reepithelization and burns healing process by using wound dressing. However, cow and pig as the major source of collagen Type-I are susceptible to infectious diseases and pig is restricted in some religions. Thus, there is need to find an alternative non-mammal collagen source. Aquatic origin collagen has been persuading as an alternative to mammalian origin. However, low denaturation temperature collagen restricts clinical application. Wound dressing with thermal stability is highly desired for burns healing. The aims of this work were the extraction of collagen Type-I from snakehead fish skin (Channa striata) and crosslinking collagen with alginate. Extraction of collagen consist of pretreatment to remove grease, hydrolysis to remove undesirable protein, and extraction to obtain acid-soluble collagen (ASC) by acetic acid. Biopolymer was synthesized by crosslinking collagen and cross- linking agent, sodium alginate (SA). Optimum concentration of collagen and SA is required. The different concentrations (1, 3, 5%) of SA were dissolved by sodium phosphate buffer. The extracted collagen was characterized using Fourier Transform Infrared Spectroscopy (FTIR) to analyze functional groups. Biopolymer was characterized for functional groups, micrograph, and thermal stability. Results reveal, functional groups Amide A (3414 cm−1), Amide I (1637 cm−1), Amide II (1548 cm−1), Amide III (13338 cm−1) refers to collagen Type-I. ASC was successfully extracted from Channa striata and classified as Type-I collagen. Addition of SA for 3% has the best thermal stability. This finding shows the potential use of this collagen-based biopolymer as a promising new dressing for burn healing.

The effect of heat treatment on microstructure and mechanical properties of SiC/Mg-Al-Sr alloy matrix composite was investigated. The heat treatment involved annealing at 425, 375, and 325°C for 4 hours, water quenching then ageing at room temperature for 48 hours. The heat treatment process caused dissolution ofs Mg2Si precipitated and decomposition of nano-SiC particles. The composites with 0.15 Vf-% nano-SiC which was treated at 425°C has reached the optimum hardness due to precipitate of the intermetallic phase. Besides, the hardness of the treated composites still has good ductility. The fracture surface of the composite consisted of numerous dimples as a result of micro voids nucleated at the interface between the matrix and SiC particles and second-phase particles as well. The fracture of heat treated composite was similar to microvoids which were nucleated mainly on nano-SiC particles as obtained during fractography analysis.