Open pore titanium foams via metal injection molding of metal powder with a space holder

Microporous Titanium through Metal Injection Moulding of Coarse Powder and Surface Modification by Plasma Oxidation

“…It should be noted that the optimum pore size range for bone ingrowth, cell attachment and proliferation is 100-500 µm [26]. However, pore sizes in the samples could be increased with the introduction of a space holder material in the feedstock mixture and removing it at a later stage during sintering [8,27].…”

“…It should be noted that the optimum pore size range for bone ingrowth, cell attachment and proliferation is 100-500 μm [26]. However, pore sizes in the samples could be increased with the introduction of a space holder material in the feedstock mixture and removing it at a later stage during sintering [8,27] The results of mechanical tests for the samples are presented in Figure 11. The compression test results indicate that samples processed by the commercial feedstock have a significantly higher yield strength compared to those processed by the coarse Ti powder, where the average yield strengths ( . )…”

“…These micropores are advantageous, particularly for biomedical applications, where they promote bone ingrowth and cell attachment [6,7]. Aside from promoting bone-implant integration, the presence of these pores can also play a significant role in reducing the stiffness of the Ti parts to match that of the bone in order to avoid the stress shielding phenomenon [8,9]. Nevertheless, wear of the tools could be an issue in using coarse powders.…”

Open Celled Porous Titanium

“…The assessment could be complicated by space holder deformation during compaction, which has been noted to occur and result in pores with elliptical shape [54] . [56] Sodium Chloride 300-500 50-500 MIM+SH -1000 ºC 4 [57] 1200 ºC PMMA D 50 =600 50-500 MIM+SH - [57] Table sugar 800-1000 800-1000 SH 500 1250 ºC 1 [43] Ammonium Hydrogen Carbonate 200-500 200-500 SH 100 1200 ºC 2 [48] Carbamide 800-2400 100-2500 SH 166 1400 ºC 1 [58] Ammonium hydrogen carbonate 100-900 Smaller SH 166 1400 ºC 1 [58] Ammonium hydrogen carbonate 500-800 300-800 SH -1200 ºC 10 [53] Polypropylene carbonate 100-600 50-500 SH 100 1000 ºC 2.5, [59] 400 5 or 10 Starch 100-400 100-300 SH 100 1200 ºC 3 [41] Polyoxymethyle ne D mean = 500 80-400 SH 50-100 1300 ºC 2 [60] Acrowax 300-500 300-500 SH 100 1100 ºC 2 [47] Potassium chloride 188-476 100-480 MIM+SH 45 1250 ºC 2 [61] 2…”

“…[73] Where single ended uniaxial pressing is used, the pressure profile is non-uniform throughout the compacted specimen (higher at the top and in the centre [84] ) thus leading to nonuniform mechanical properties; correlations have been found with the expected pressure distribution and the fracture lines in tested samples. [84] As metal powder and space holder sizes [73] Sodium chloride < 290 50-300 MIM þ SH 100 1 150 2 [74] Sodium chloride 300-500 50-500 MIM þ SH -1 000 4 [75] 1 200 PMMA D 50 ¼ 600 50-500 MIM þ SH - [75] Table sugar 800-1 000 800-1 000 SH 500 1 250 1 [61] Ammonium Hydrogen Carbonate 200-500 200-500 SH 100 1 200 2 [66] Carbamide 800-2 400 100-2 500 SH 166 1 400 1 [76] Ammonium hydrogen carbonate 100-900 Smaller SH 166 1 400 1 [76] Ammonium hydrogen carbonate 500-800 300-800 SH -1 200 10 [71] Polypropylene carbonate 100-600 50-500 SH 100 1 000 2.5, [77] 400 5 or 10 Starch 100-400 100-300 SH 100 1 200 3 [59] Polyoxymethylene D mean ¼ 500 80-400 SH 50-100 1 300 2 [78] Acrowax 300-500 300-500 SH 100 1 100 2 [65] Potassium chloride 188-476 100-480 MIM þ SH 45 1 250 2 [79] Magnesium 425-600 Avg. 525 SH 500 1 200 1 [68] High carbon steel wire 250-500 250-500 SH 350 1 050 12 [69] and densities are frequently different, segregation can occur, which results in inhomogeneous distribution of the space holder particles in the Ti powder and a reduction in pore interconnectivity; to overcome this, a polymeric binder may be included in the mixture.…”