Effect of Al addition and space holder content on microstructure and mechanical properties of Ti2Co alloys foams for bone scaffold application

Effect of the Processing Parameters on the Porosity and Mechanical Behavior of Titanium Samples with Bimodal Microstructure Produced via Hot Pressing

“…Powder metallurgy, in combination with the space-holder technique, represents a cost-effective and flexible way to obtain components with a high-degree of porosity (35–80%) and a homogeneous distribution of pores throughout the volume [ 15 , 16 , 17 ]. Particles commonly used as space-holders include NH 4 HCO 3 [ 5 , 18 , 19 , 20 , 21 , 22 ], NaCl [ 17 , 18 , 21 , 23 , 24 ], starch [ 25 , 26 ], Mg [ 27 , 28 , 29 ], PMMA [ 30 , 31 ], saccharose crystals [ 26 , 32 ], PVA [ 33 ], and carbamide [ 15 , 34 , 35 ], which can be eliminated at a relatively low temperature, or can be easily removed by a dissolution process, generally in water [ 3 ]. NH 4 HCO 3 is one of the preferred spacer particles due to its moderate decomposition temperature, which makes it easily and completely removable, ensuring a low uptake of impurities such as oxygen, nitrogen, and carbon [ 17 ].…”

Titanium Foam for Dental Implant Applications: A review

“…This approach has various advantages. The shape, size, porosity, and distribution of the pores in the foam material can simply be modified by varying the shapes, sizes, and volume fractions of spacers in the metal powder [13]. Fig 3 depicts the powder metallurgy approach for producing foam using a space holder.…”

Understanding the Synergetic Effects of Mechanical Milling and Hot Pressing on Bimodal Microstructure and Tribo-Mechanical Behavior in Porous Ti Structures

“…However, these materials have two main drawbacks that compromise implants reliability: stress-shielding phenomenon and poor osseointegration [5]. The stress-shielding phenomenon is caused by the mismatch between the Young's modulus of the material (100-110 GPa) and the cortical bone (20)(21)(22)(23)(24)(25), which promotes bone resorption and the eventual fracture of the host tissue [6,7]. Poor osseointegration of the implants could be inherent to the biological response of the titanium surfaces, and/or to potential infections due to the proliferation and growth of bacteria that inhibit the formation of new bone [8].…”

“…A wide range of materials can be employed as space-holder particles, from ceramic particles, soluble salts, polymers, to metallic spheres [20]. For biomedical applications, the commonly materials for space-holders are NH 4 HCO 3 [5,12,[21][22][23], NaCl [20,21,[23][24][25], starch [26,27], Mg [1,28,29], PMMA [30,31], saccharose crystals [27,32], PVA [33], and carbamide [19,34,35], due to its easy removal ability by decomposition at relatively low temperatures or by means of dissolution process, generally in water [9,12]. According to the literature, the use of NaCl as a spacer has advantages, such as low cost, rapid dissolution in water, reduced metal etching during dissolution, as well as much lower toxicity due to residual content [36,37].…”