Fatigue Behavior and Apatite Precipitation of Plasma-Sprayed HAp Coating on Commercially Pure Titanium Substrate in Simulated Body Fluid (SBF)

2012 ◽  
Vol 506 ◽  
pp. 66-69 ◽  
Author(s):  
Teerawat Loanapakul ◽  
A. Rakngarm Nimkerdphol ◽  
Yuichi Otsuka ◽  
Yoshiharu Mutoh

Plasma sprayed Hydroxyapatite (HAp) coating on commercially pure titanium (cp-Ti) is widely used as implant materials. In this study, fatigue behavior of as-sprayed HAp top coat with HAp/Ti bond coat specimen under ambient environment (A-HTi) as well as under simulated body fluid, SBF, environment (I-HTi) at 36.5°C was investigated by four point bending fatigue test at a stress amplitude of 170 MPa under various frequencies. In order to investigate apatite precipitation during fatigue loading, the test specimen was immersed in SBF at 36.5°C during the fatigue test. For comparison, the test specimen was immersed in SBF at 36.5°C for a day to a week without fatigue loading and then the fatigue test of the immersed specimen was carried out under ambient environment (I-A-HTi). The fatigue loading would not influence the apatite precipitation in the HAp coating layer of the specimen. The fatigue lives of the I-HTi and I-A-HTi specimens were shorter compared to that of A-HTi specimen. The shorter fatigue lives of the I-HTi and I-A-HTi specimens would result from the attack of SBF on titanium substrate. However, the apatite precipitation in the coating layer up to one week immersion did not significantly influence the delamination between HAp top coat and cp-Ti substrate under the bending fatigue.

2010 ◽  
Vol 452-453 ◽  
pp. 857-860 ◽  
Author(s):  
Teerawat Loanapakul ◽  
Yuichi Otsuka ◽  
Yoshiharu Mutoh

In the conventional hydroxyapatite (HAp) coating, the surface of commercially pure titanium (Cp-Ti) is blasted with Al2O3 grid-blasting powders and then plasma-sprayed with HAp. To improve the adhesive strength of HAp coating, the grid-blasting with Al2O3 powders and subsequently wet-blasting by HAp/Ti mixed powders were applied on Cp-Ti substrate at ambient temperature. On the wet-blasted surface of Cp-Ti, two-layers of coating composed of HAp/Ti bond coat and HAp top coat were deposited by plasma spraying. Both types of HAp-coated specimen could survive up to 107 cycles without spallation of HAp coating at the stress amplitude of 120 MPa under four point bending fatigue test. In order to clarify mechanical failure behavior of the coatings and Ti substrate, acoustic emission (AE) signals during the entire fatigue process were observed. Relationship between AE behavior and cracking process of coated specimen was evaluated. HAp top coat with HAp/Ti bond coat strongly improved the adhesive and cohesive strength, where dense AE signals occurred at the early stage of fatigue test corresponded to plastic deformation of Ti substrate and micro-cracks in coated layers. AE signals occurred at the final stage corresponded to crack propagation in coated specimen and spallations of coated layers.


2013 ◽  
Vol 739 ◽  
pp. 196-200 ◽  
Author(s):  
T.M. Yue ◽  
K.J. Huang ◽  
H. Xie

A three-layer Ti-Si graded coating was fabricated on a commercially pure titanium substrate by laser cladding with Ti-5.8 at%Si, Ti-9.0 at%Si and Ti-13.5 at%Si mixed powders. The microstructure of the three layers comprised Ti-Si solid solutions (Ti) and the Ti5Si3 compound. As the silicon content was increased, the microstructure along the direction of deposition underwent a series of changes, including replacement of the (Ti) phase by the primary Ti5Si3 phase, and a change of the (Ti)/Ti5Si3 eutectic growth from lamellar to anomalous.


2012 ◽  
Vol 548 ◽  
pp. 174-178 ◽  
Author(s):  
Chong Yang Gao ◽  
Wei Ran Lu

By using a dislocation-based plastic constitutive model for hcp metals developed by us recently, the dynamic thermomechanical response of an important industrial material, commercially pure titanium (CP-Ti), was described at different temperatures and strain rates. The constitutive parameters of the material are determined by an efficient optimization method for a globally optimal solution. The model can well predict the dynamic response of CP-Ti by the comparison with experimental data and the Nemat-Nasser-Guo model.


Author(s):  
Karibeeran Shanmuga Sundaram ◽  
Gurusami Kiliyappan ◽  
Senthil Kumaran Selvadurai

Laser shock peening (LSP) is one of the innovative technique that produces a compressive residual stress on the surface of metallic materials, thereby significantly increasing its fatigue life in applications where failure is caused by surface-initiated cracks. The specimens were treated with laser shock waves with different processing parameters, and characterization studies were made on treated specimens. The purpose of the present study was to investigate the influence of Nd:YAG laser on commercially pure titanium (CP-Ti) used in prosthetic dental restorations. The treatment influenced change in microstructure, micro hardness, surface roughness, and wear resistance characteristics. Though CP-Ti is considered as an excellent material for dental applications due to its outstanding biocompatibility, it is not suitable when high mastication forces are applied. In the present study, pulsed Nd:YAG laser surface treatment technique was adopted to improve the wear resistance of CP-Ti. The wear test pin specimens of CP-Ti were investment cast with centrifugal titanium casting machine. The wear properties of specimens were evaluated after LSP on a “pin-on-disc” wear testing tribometer, as per ASTM G99-05 standards. The results of the wear experiment showed that the treated laser surface has higher wear resistance, micro hardness, and surface roughness compared to as-cast samples. The improvement of wear resistance may be attributed due to grain refinement imparted by LSP processes. The microstructure, wear surfaces, wear debris, and morphology of the specimen were analyzed by using optical electron microscope, scanning electron microscope, and X-ray diffraction (XRD). The data were compared using ANOVA and post-hoc Tukey tests. The characteristic change resulted in increase in wear resistance and decrease in wear rate. Hence, it is evident that the more reliable and removable partial denture metal frameworks for dental prostheses may find its applications.


2005 ◽  
Vol 19 (2) ◽  
pp. 139-143 ◽  
Author(s):  
Wagner Sotero Fragoso ◽  
Guilherme Elias Pessanha Henriques ◽  
Edwin Fernando Ruiz Contreras ◽  
Marcelo Ferraz Mesquita

Commercially pure titanium (CP Ti) has been widely applied to fabricate cast devices because of its favorable properties. However, the mold temperature recommended for the manufacture of casts has been considered relatively low, causing inadequate castability and poor marginal fit of cast crowns. This study evaluated and compared the influence of mold temperature (430°C - as control, 550°C, 670°C) on the marginal discrepancies of cast CP Ti crowns. Eight bovine teeth were prepared on a mechanical grinding device and impressions were used to duplicate each tooth and produce eight master dies. Twenty-four crowns were fabricated using CP Ti in three different groups of mold temperature (n = 8): 430°C (as control), 550°C and 670°C. The gap between the crown and the bovine tooth was measured at 50 X magnification with a traveling microscope. The marginal fit values of the cast CP Ti crowns were submitted to the Kruskal-Wallis test (p = 0.03). The 550°C group (95.0 µm) showed significantly better marginal fit than the crowns of the 430°C group (203.4 µm) and 670°C group (213.8 µm). Better marginal fit for cast CP Ti crowns was observed with the mold temperature of 550°C, differing from the 430°C recommended by the manufacturer.


2010 ◽  
Vol 654-656 ◽  
pp. 2172-2175
Author(s):  
Kyosuke Ueda ◽  
Hajime Suto ◽  
Kaori Nakaie ◽  
Takayuki Narushima

The surface modification of commercially pure titanium (CP Ti) by pack cementation treatment at 973 K using tetracalcium phosphate (Ca4(PO4)2O, TTCP) slurry was investigated. An HAp phase and a CaTiO3 phase were observed on the reaction layer of the CP Ti substrate after pack cementation treatment at 973 K for 86.4 ks. TTCP powder decomposed to HAp and CaO, and CaO reacted with TiO2 to form CaTiO3. The reaction layer on the CP Ti substrate consisted of inner and outer layers and the particles were in the outer reaction layer. The pores observed on the reaction layer were formed by the detachment of particles from the outer layer. The bonding strength of the reaction layer was 68.1 MPa. Apatite completely covered the surface of the pack-cementation-treated CP Ti after immersion in Kokubo solution for 21.6 ks; such rapid apatite formation suggests that pack cementation treatment improves the biocompatibility of titanium.


2018 ◽  
Vol 53 (9) ◽  
pp. 6872-6892 ◽  
Author(s):  
S. Khayatzadeh ◽  
M. J. Thomas ◽  
Y. Millet ◽  
S. Rahimi

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