Preparation of Hydroxyapatite/Chitosan Biological Coatings on Carbon/Carbon Composites

2010 ◽  
Vol 434-435 ◽  
pp. 502-505
Author(s):  
Ying Hua Li ◽  
Li Yun Cao ◽  
Jian Feng Huang ◽  
Xie Rong Zeng

Hydroxyapatite/Chitosan (HAp/CS) bio-coatings were prepared on the surface of carbon/ carbon (C/C) composites by hydrothermal electrophoretic deposition, using sonochemical process resulted HAp nanoparticles, isopropyl alcohol and chitosan as raw materials. The influences of hydro- thermal conditions and deposition voltage on the microstructures and morphologies of the as-prepared coatings were investigated. It was shown that homogenous and dense HAp/CS coatings on C/C composites are obtained by hydrothermal electrophoretic deposition. With the increase of deposition voltage, density and homogeneity of the as-prepared HAp/CS composite coatings are well improved. Due to the growth of HAp nanoparticles in the hydrothermal condition, the subsequent heat treatment of the HAp/CS coatings is not needed.

Author(s):  
Muhammad Wahaj ◽  
Usama Saleem ◽  
Farasat Iqbal ◽  
Muhammad Yasir ◽  
Abdul Wadood ◽  
...  

In this study, silver-strontium doped hydroxyapatite (AgSr-HA)/chitosan composite coatings were deposited on stainless steel (SS) substrate via electrophoretic deposition (EPD) technique. The EPD parameters such as the concentration of Ag Sr-HA particles in the suspension, applied voltage and deposition time were optimized on by the Taguchi Design of Experiment (DoE) approach. DOE approach elucidated that the “best” coating was obtained at; the deposition voltage of 20V, deposition time of 7 minutes, and at 5 g/L of Ag Sr-HA particles in the suspension. The optimum coatings were characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. SEM images confirmed the deposition of chitosan/Ag Sr-HA on the SS substrate. The wettability studies indicated the hydrophilic nature of the chitosan/Ag Sr-HA coatings, which confirmed the suitability of the developed coatings for orthopedic applications. The average surface roughness of the chitosan/Ag Sr-HA coatings was in a suitable range for the attachment of bone marrow stromal cells. Chitosan/Ag Sr-HA coatings showed a potent antibacterial effect against the Gram-Positive and Gram-negative bacteria.


2021 ◽  
Vol 15 (3) ◽  
pp. 211-218
Author(s):  
Guobing Ying ◽  
Cong Hu ◽  
Lu Liu ◽  
Cheng Sun ◽  
Dong Wen ◽  
...  

High-purity and bulk Ta4AlC3 ceramics were successfully fabricated by spark plasma sintering (SPS) and subsequent heat treatment, using the raw materials including TaC and Ta2AlC powders. These raw materials were first synthesized by self-propagation high temperature synthesis from elements tantalum, aluminium and carbon black powders, followed by pressure-less sintering. The as-fabricated bulk Ta4AlC3 was relatively stable when subjected to heat treatment at elevated temperature of 1500?C. Moreover, prolonging the heat treatment time resulted in bigger grain sizes and higher densities of the Ta4AlC3. The flexural strength and the fracture toughness of the Ta4AlC3 fabricated by SPS were found to be 411MPa and 7.11MPa?m1/2, respectively. After the heat treatment at 1500?C for 8 h, the flexural strength and the fracture toughness of the Ta4AlC3 could reach 709MPa and 9.23MPa?m1/2, respectively. The special structural characteristics of the ternary ceramics and the increase of density after the heat treatment are the main reasons for the variation in mechanical properties of ternary ceramics.


Alloy Digest ◽  
2013 ◽  
Vol 62 (9) ◽  

Abstract Böhler (or Boehler) W403 VMR is a tool steel with outstanding properties, based not only on a modified chemical composition, but on the selection of highly clean raw materials for melting, remelting under vacuum (VMF), optimized diffusion annealing, and a special heat treatment. This datasheet provides information on composition, physical properties, and elasticity. It also includes information on forming and heat treating. Filing Code: TS-721. Producer or source: Böhler Edelstahl GmbH.


2021 ◽  
Vol 285 ◽  
pp. 129123
Author(s):  
Xiaohao Sun ◽  
Debao Liu ◽  
Minfang Chen ◽  
Weiwei Zhou ◽  
Naoyuki Nomura ◽  
...  

2021 ◽  
Vol 804 ◽  
pp. 140760
Author(s):  
Hamidreza Koohdar ◽  
Pouya Hakimipour ◽  
Hamid Reza Jafarian ◽  
Terence G. Langdon ◽  
Mahmoud Nili-Ahmadabadi

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