scholarly journals Detonation Spraying of Hydroxyapatite on a Titanium Alloy Implant

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4852
Author(s):  
Natalia V. Bulina ◽  
Denis K. Rybin ◽  
Svetlana V. Makarova ◽  
Dina V. Dudina ◽  
Igor S. Batraev ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Single Phase ◽  
Tooth Enamel ◽  
Flow Direction ◽  
Feedstock Powder ◽  
Detonation Spraying ◽  
Metallic Implants ◽  
Ha Coating ◽  
Developed Surface ◽  
Overall Performance

Hydroxyapatite (HA), the major mineral component of tooth enamel and natural bones, is a good candidate for bone tissue engineering. Synthetic HA is used for making coatings on metallic implants intended for medical applications. A HA coating renders the implant biocompatible and osteoinductive. In addition, it improves fixation and the overall performance of the implanted object. In the present work, HA coatings were deposited on a medical titanium alloy implant with mesh geometry and a developed surface by detonation spraying. The feedstock powder was HA obtained by the dry mechanochemical method. Single-phase HA coatings were obtained. The coatings were formed not only on the surfaces normal to the particle flow direction, but also on the sides of the mesh elements. Despite partial melting of the powder, no decomposition of HA occurred. This work demonstrates the prospects of detonation spraying for the production of HA coatings on metallic implants with complex geometries.

scholarly journals Dip-Coating of Calcium Hydroxyapatite on Titanium Alloy (ti-6ai-4v) and Stainless Steel (316L) Substrates

1999 ◽  
Vol 599 ◽  
Author(s):  
B. Mavis ◽  
A. C. Tas
Keyword(s):  
Stainless Steel ◽  
Titanium Alloy ◽  
Calcium Hydroxyapatite ◽  
Dip Coating ◽  
Orthopaedic Implants ◽  
Stainless Steel 316L ◽  
Metal Implants ◽  
Ha Coating ◽  
Sample Characterization

AbstractTitanium alloy (Ti-6AI-4V) and stainless steel (316L) are two of the most commonly used materials in the manufacture of orthopaedic implants. To achieve better biocompatibility with bone, metal implants made of 316L or Ti-6Al-4V are often coated with calcium hydroxyapatite (HA) bioceramics. This paper is to describe a new dipping solution recipe used for HA coating. Sample characterization was performed by SEM and XRD.

Effectiveness Analysis of Non-Mechanical Micro-Valvular Conduit in Single Phase Flow

2012 ◽  
Author(s):  
Bong Joo Lee ◽  
J. R. Culham
Keyword(s):  
Single Phase ◽  
Complex Geometry ◽  
Flow Direction ◽  
Thermal Dissipation ◽  
Computational Simulations ◽  
Steady State Condition ◽  
Diaphragm Pump ◽  
Effectiveness Analysis ◽  
Mechanical Valves ◽  
Macro Scale

The non-mechanical valvular conduit, which uses no moving parts but instead relies on a complex geometry to regulate flow, is studied through a combination of numerical, computational and experimental methods. This study is based on using water as the fluid at standard state properties. A numerical model is developed to evaluate the effectiveness of the non-mechanical valve’s intricate geometry. Then computational simulations of the oscillating/pumping sequence of the valvular conduit are conducted to examine the effectiveness of the valve when placed in use for a diaphragm pump. Results demonstrate that the non-mechanical valvular conduit can be an effective application for a diaphragm pump at the micro or macro-scale without requiring valvular mechanics. In computational simulations, when non-mechanical valves are positioned at both the inlet and exit of a diaphragm, the positive circulation of fluid is enhanced by 38% which is sufficient to meet the thermal dissipation requirements of an Intel Pentium D processor (i.e. 130 W). In addition, the experimental results in steady state condition demonstrated that the valvular design regulates the flow direction by producing diodicity (a measure of favorable flow direction) of 2.44.

An Experimental Investigation of Gas-Liquid Heat Transfer in Rectangular Micro-Channels

2013 ◽  
Author(s):  
Sira Saisorn ◽  
Somchai Wongwises ◽  
Piyawat Kuaseng ◽  
Chompunut Nuibutr ◽  
Wattana Chanphan
Keyword(s):  
Heat Transfer ◽  
Single Phase ◽  
Flow Direction ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase ◽  
Camera System ◽  
Micro Channels ◽  
Flow Mechanisms

The investigations of heat transfer and fluid flow characteristics of non-boiling air-water flow in micro-channels are experimentally studied. The gas-liquid mixture from y-shape mixer is forced to flow in the 21 parallel rectangular microchannels with 40 mm long in the flow direction. Each channel has a width and a depth of 0.45 and 0.41 mm, respectively. Flow visualization is feasible by incorporating the stereozoom microscope into the camera system and different flow patterns are recorded. The experiments are performed under low superficial velocities. Two-phase heat transfer gives better results when compared with the single-phase flow. It is found from the experiment that heat transfer enhancement up to 53% is obtained over the single-phase flow. Also, the change in the configuration of the inlet plenum can result in the different two-phase flow mechanisms.

Cytocompatibility Comparative Study of Hydroxyapatite Coating on Titanium Alloy Treated with Two Chemical Routes

2013 ◽  
Vol 658 ◽  
pp. 61-66
Author(s):  
Qing Zong Si ◽  
Xiao Li An ◽  
Yang Li ◽  
Bin Liu ◽  
Jin Qing Wang
Keyword(s):  
Titanium Alloy ◽  
In Vitro Cytotoxicity ◽  
Combination Method ◽  
Cytotoxicity Test ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Ha Coating ◽  
Cell Adhesion And Proliferation

In order to prepare bioactive hydroxyapatite (Ca10 (PO4)6(OH) 2, HA) coating with ideal biocompatibility, the surface of titanium alloy was treated with the two kinds of chemical methods, which are the acid-alkali-combination method and Self-polymerization-adhesion of dopamine. After pretreatment, the treated titanium alloy plates were immersed in simulated body fluid (SBF) to form HA coating on their surface. The chemical composition of the coating was analyzed by an X-ray diffraction (XRD) and the morphology was observed by a scanning electron microscope (SEM). After that, the plates were training in vitro cytotoxicity test with MC3T3-E1 osteoblasts. Compared with the results of cell culture, the method of Self- polymerization -adhesion of dopamine showed better cell adhesion and proliferation..

Stability of Single-Phase Natural Circulation With Inverted U-Tube Steam Generators

1988 ◽  
Vol 110 (3) ◽  
pp. 735-742 ◽  
Author(s):  
J. Sanders
Keyword(s):  
Mathematical Model ◽  
Single Phase ◽  
Flow Direction ◽  
Natural Circulation ◽  
Boussinesq Equations ◽  
Test Facility ◽  
Normal Flow ◽  
Steam Generators ◽  
One Dimensional ◽  
Water Flows

For natural circulation it is shown that parallel flow in the tubes of an inverted U-tube steam generator can be, at certain power levels, unstable. A mathematical model, based on one-dimensional Oberbeck-Boussinesq equations, shows that stability can be attained if in some tubes the water flows backward, opposite to the normal flow direction. The results are compared to measurements obtained from the natural circulation test A2-77A in the LOBI-MOD2 integral system test facility.

Cryogenic Single-Phase Heat Transfer in a Microscale Pin Fin Heat Sink

2013 ◽  
Author(s):  
Eric D. Truong ◽  
Erfan Rasouli ◽  
Vinod Narayanan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Single Phase ◽  
Flow Direction ◽  
Heat Sinks ◽  
Variable Cross ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Heat Transfer Coefficients

A combined experimental and computational fluid dynamics study of single-phase liquid nitrogen flow through a microscale pin-fin heat sink is presented. Such cryogenic heat sinks find use in applications such as high performance computing and spacecraft thermal management. A circular pin fin heat sink in diameter 5 cm and 250 micrometers in depth was studied herein. Unique features of the heat sink included its variable cross sectional area in the flow direction, variable pin diameters, as well as a circumferential distribution of fluid into the pin fin region. The stainless steel heat sink was fabricated using chemical etching and diffusion bonding. Experimental results indicate that the heat transfer coefficients were relatively unchanged around 2600 W/m2-K for flow rates ranging from 2–4 g/s while the pressure drop increased monotonically with the flow rate. None of the existing correlations in literature on cross flow over a tube bank or micro pin fin heat sinks were able to predict the experimental pressure drop and heat transfer characteristics. However, three dimensional simulations performed using ANSYS Fluent showed reasonable (∼7 percent difference) agreement in the average heat transfer coefficients between experiments and CFD simulations.

scholarly journals Structural transformations of a gas-atomized Al62.5Cu25Fe12.5 alloy during detonation spraying, spark plasma sintering and hot pressing

2021 ◽  
Vol 53 (3) ◽  
pp. 379-386
Author(s):  
Igor Batraev ◽  
Witor Wolf ◽  
Boris Bokhonov ◽  
Arina Ukhina ◽  
Ivanna Kuchumova ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Hot Pressing ◽  
Single Phase ◽  
Complex Structure ◽  
Icosahedral Phase ◽  
Structural Transformations ◽  
Detonation Spraying ◽  
Complete Melting ◽  
Plasma Sintering ◽  
Spark Plasma

In this work, we traced structural transformations of an Al62.5Cu25Fe12.5 alloy, in which a quasicrystalline icosahedral phase (i-phase) can be formed, upon spraying onto a substrate and consolidation from the powder into the bulk state. The Al62.5Cu25Fe12.5 powder was obtained by gas atomization and consisted of i-phase and ?-phase AlCu(Fe). The powder was detonation sprayed (DS) and consolidated by spark plasma sintering (SPS)/hot pressing (HP). During DS, the particles experienced partial or complete melting and rapid solidification, which resulted in the formation of coatings of a complex structure. The composite regions containing i-phase were inherited from the powder alloy. The fraction of the material that experienced melting solidified as ?-phase AlFe(Cu) in the coating. It was suggested that the difficulty of obtaining i-phase upon post-spray annealing is related to aluminum depletion of the alloy during DS. During SPS and HP, the elemental composition of the alloy was preserved, while the exposure to an elevated temperature led to phase homogenization. SPS and HP conducted at 700?C resulted in full densification and the formation of a single-phase quasicrystalline alloy. The sintered single-phase alloy showed a higher microhardness in comparison with the DS coatings.

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