Fabrication of high porous NiTi shape memory alloy by metal injection molding

Metals for bone implants. Part 1. Powder metallurgy and implant rendering

“…While Guaxin et al [131] use the conventional MIM process for the production of porous NiTi from elemental powder, Bram et al [132,133] and Köhl et al [134][135][136] adopted the space-holder technique to create highly porous NiTi with large pore sizes and good structural and functional properties by MIM from pre-alloyed powder (see Figure 7). This procedure starts with creating a feedstock of NiTi powder, NaCl space-holders and a binder system (amide wax and polyethylene wax) by means of mixing in a heated kneader.…”

Design of water debinding and dissolution stages of metal injection moulded porous Ti foam production

“…The latter is usually carried out in either water or other solvents such as hexane. Hitherto, most of the reports on the production of Ti foams via MIMspace holder method used paraffin wax as a major binder constituent and organic solvent debinding for binder removal [8,9]. However, one significant problem is that the debinding and space holder removal processes can often take a very long time (up to 72 hours) [10].…”

“…However, one significant problem is that the debinding and space holder removal processes can often take a very long time (up to 72 hours) [10]. Another problem is that environmentally unfriendly organic solvents are used for paraffin wax debinding such as Chloroform [9] and hexane [8,10,11]. In this paper, the use of water soluble polymer, namely Poly ethylene glycol (PEG) as a main constituent in the binder and its debinding behaviour will be studied for the production of Ti foams by the MIM-space holder method.…”

Metal injection moulding of titanium and titanium alloys: Challenges and recent development

“…Although, currently there is no industrial production for porous medical implants using MIM technology, there are many research and development works that have evaluated the possibility of this technique [17,19,88,[120][121][122][123]. For example, Carreno-Morelli et al [19] manufactured highly porous Ti parts using MIM of titanium hydride powders and the space holder technique with very low elastic modulus in the range of 4-22 GPA, which is close to that of human bone.…”