Titanium has been widely used in biomedical implant applications due to its excellent mechanical properties and biocompatibility. However, manufacturing titanium was quite challenging due to the need for high temperature while having high reactivity. Therefore, spark plasma sintering (SPS) is proposed as an advance rapid sintering technique which allows the fabrication of bulk and porous titanium for biomedical application. This review aims to explore the recent status of titanium alloys prepared by the SPS method. There are two common approaches of titanium development by the SPS method, develop a bulk titanium alloy, or develop porous titanium. The development of titanium for biomedical implant application was done by improving biocompatibility alloy and repair some unsatisfactory mechanical properties. Some low toxicity of titanium alloys (Aluminum free and Vanadium free) had been studied such as Ti–Nb, Ti–Zr, Ti–Ag, Ti–Mg, Ti–Nb–Zr, Ti–Nb–Cu, Ti–Nb–Zr–Ta, etc. SPS was shown to increase the mechanical properties of titanium alloys. However, porous titanium alloys prepared by SPS had gained much attention since it may produce titanium with lower elastic modulus in such a short time. Low elastic modulus is preferable for implant material because it can reduce the risk of implant failure due to the stress-shielding effect. Besides mechanical properties, some corrosion resistance and the biocompatibility of titanium are also reviewed in this paper.

Generally, metal injection molding (MIM) method utilizes SS 17-4 PH as material for application of orthodontic bracket. One of the process of MIM is thermal debinding, which binder is eliminated by thermal energy. In this study, thermal debinding process is conducted with variation of temperature, i.e. 480, 510, and 540°C, holding time, i.e. 0.5, 1 and 2 hours, heating rate, i.e. 0.5, 1, 1.5, and 2°C/min.The effect of temperature shows that the increased temperature will result in the mass reduction percentage due to formation of oxide on the sample, which will be proven through TGA testing. The highest mass reduction was 6.4137 wt% which was obtained at 480°C. For the variation of holding time, the longer the holding time will result in increased mass reduction and the highest mas reduction was 6.255 wt% which was obtained during 2 hours of holding time. For the heating rate, the slower the heating rate will result in increased mass reduction and decreased the presence of crack formation. The best variable was obtained at heating rate of 0.5°C/min, which resulted mass reduction of 6.2488 wt% and less crack formation.

Demand for dental health care is increasing, especially in the Orthodontic field. The main objective of orthodontic treatment is to restore malocclusion conditions. Malocclusion causes aesthetics issues for the patient’s face and several discomforts like a difficulty in breathing or swallowing or speaking. If not repaired, a malocclusion could lead to other diseases, such as a greater risk of perforated teeth, gum irritation and temporomandibular disorder or pain in the lower jaw. Malocclusion can be remedied by Orthodontic Brackets. This research aim is to fabricate an orthodontic bracket that is suitable for the teeth structure of the Indonesian people. The fabrication method uses an Investment Casting process. The results show that orthodontic brackets have been successfully produced within an acceptable geometric tolerance, with the exception that surface finish quality has to be improved. Keywords: Investment casting; Malocclusion; Orthodontic; Orthodontic bracket Published at: IJTech Vol 6, No 4 (2015) DOI: http://dx.doi.org/10.14716/ijtech.v6i4.1862

Saprolite and limonite have different behaviour in the carbothermic reduction process due to the differences in their atomic structures. This work investigates the kinetic study of these two different kinds of lateritic nickel ores. Nickel ore, coal, sodium sulfate, and calcium oxide were mixed, then pelletised into 10–15 mm diameters. The pellets were reduced with a non-isothermal condition using a muffle furnace at 950–1150 °C for 5–120 min. The reduced pellets were crushed into less than 74 µm prior to the wet magnetic separation process to obtain concentrates (ferronickel) and tailings (impurities). The result showed that the reduction rate for both lateritic nickel ores increased with the increase of reduction temperature and holding time. The Ginstling-Brouhnstein model was appropriate to describe the diffusion mechanism of the reduction process of limonite and saprolite. The activation energy in the reduction of limonite was lower than in saprolite. It indicated that the iron and nickel in magnesium silicate in saprolite have lower reducibility than the oxide structure in limonite. Modifying basicity in nickel laterite with CaO addition could also reduce the activation energy.

In this study, novel multi-component Ti-Mo-Nb-Sn-Mn alloys were developed as a solution to the mismatch in elastic moduli of implant and human bone and toxicity of the Ti-6Al-4V alloy commonly used in the biomedical field. This study is aimed to investigate the effects of Sn and Mn addition as beta stabilizers on the microstructural transformation, mechanical properties, and corrosion behavior of the alloys. Ti-6Mo-6Nb-xSn-xMn (x = 0, 4, or 8) alloys were re-melted five times in an arc re-melting process under an argon atmosphere and the obtained ingots were characterized using optical microscopy, X-ray diffractometry, ultrasound, a Vicker’s hardness tester, and polarization tests in a Ringer solution. The results show that a Ti-6Mo-6Nb-xSn-xMn alloy had a lower elastic modulus and better corrosion resistance than those of commercial Ti-6Al-4V alloy, making it a potential candidate for use in the biomedical field.

In producing thin wall ductile iron (TWDI) cooling rate must be strictly maintained to prevent carbide formation. There are many ways to control cooling rate BUT the most independent one is by casting design. By choosing this parameter major changes in equipment and raw material used in the foundry can be avoided. This paper discusses the effect of gating system design on microstructure and mechanical properties of 5 mm TWDI plate. A casting design based on vertical gating system is made to produce 1, 2, 3, 4, and 5 mm TWDI plates. Plate with 5 mm thickness becomes an interesting subject due to its position as the thickest and furthest from ingate in casting design with a new concept. There are three designs coded as T1, T2, and T3. These three designs were also used in making 1 and 3 mm TWDI plates of which the result has been published. The plate with 5 mm thickness will be used for automotive components. Casting design simulation for filling flow and solidification were conducted with Z-Cast. Result of flow simulation shows that the filling flow happens in two kinds. Result of solidification shows that T3 has the highest solidification rate. In the experiment, the moulds used were furan sand. Experiment result shows that all the designs have microstructure consisting of nodule graphite in ferrite matrix, no trace of carbide and skin effect are formed. Skin effect length is various for all designs. The highest nodularity is only 72% and nodule count shows only 700 nodules/mm2. Brinell hardness number for all design is beyond standard given by JIG G5502. As for UTS and elongation none of the designs exceed the minimal standard. Experiment results confirms simulation result. Compared to the previous result nodularity and nodule count decrease and curve trends for every result are not similar.