FABRICATION OPTIMIZATION OF NANOHYDROXYAPATITE ARTIFICIAL BONE SCAFFOLDS

NANO ◽  
2012 ◽  
Vol 07 (03) ◽  
pp. 1250015 ◽  
Author(s):  
CIJUN SHUAI ◽  
CHENGDE GAO ◽  
YI NIE ◽  
PENGJIAN LI ◽  
JINGYU ZHUANG ◽  
...  
Keyword(s):  
Laser Power ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Artificial Bone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bone Scaffolds ◽  
Optimum Parameters ◽  
Preheating Temperature ◽  
Ft Ir

Serious microcracks often occur on the surface of nanohydroxyapatite (n-HAP) artificial bone scaffolds prepared by selective laser sintering (SLS) technology. In this study, we found that appropriate preheating before sintering can reduce and attenuate the cracks. The microstructure and morphology of sintered n-HAP were tested at different preheating temperature and laser sintering speed with scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The experiments showed that the cracks gradually reduced and then disappeared when the preheating temperature increased from 0°C to 600°C while other parameters remain unchanged. The n-HAP particles gradually fused and grew up, while the grain size of sintered n-HAP will be attenuated with the increase of preheating temperature. As the thermal conductivity of n-HAP increases with increased preheating temperature, the temperature drops quickly, inhibiting greatly the grain growth of n-HAP. We obtained a group of optimum parameters when the sintered n-HAP still maintains nanostructure and possesses the optimal comprehensive performances, that is, laser power is 26 W, spot diameter is 4 mm, sintering speed is 200 mm/min, layer thickness is 0.4 mm, layer density is 852 kg/m3, and optimized preheating temperature is 600°C. These data illustrated that the cracks of sintered n-HAP can be eliminated at appropriate preheating temperature and sintering speed. This provided experimental optimal condition for the preparation of artificial bone scaffolds with nanohydroxyapatite ceramics.

Sintering quality and parameters optimization of sisal fiber/PES composite fabricated by selective laser sintering (SLS)

2020 ◽  
pp. 089270572093917
Author(s):  
Aboubaker IB Idriss ◽  
Jian Li ◽  
Yanling Guo ◽  
Yangwei Wang ◽  
Xingdong Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Process Parameters ◽  
Laser Power ◽  
Selective Laser Sintering ◽  
Scanning Speed ◽  
Laser Sintering ◽  
Sisal Fiber ◽  
Optimum Parameters ◽  
Preheating Temperature

This article aims to improve the sintering quality of the sisal fiber/poly-(ether sulfone) (PES) composite (SFPC) part fabricated via selective laser sintering (SLS). The sisal fiber and PES powders were proposed as the feedstock of the SFPC powder bed for SLS. An orthogonal experimental methodology with four levels and five factors was applied to optimize the process parameters for the single-layer sintering experiment. The mechanical properties and accurate dimensions of the sintered part were tested using a universal testing machine and Vernier caliper. The preheating temperature, scanning speed, and laser power were selected as influencing factors on the mechanical properties and accuracy dimensions of the SFPC part. Furthermore, the influence factors on the quality of the sintered part were studied and analyzed. Additionally, the synthesis weighted scoring method was used to determine the optimum parameters of the SLS part. The results showed that the optimal parameters (factors) were preheating temperature of 82°C, scanning speed of 2 m s−1, laser power of 14 W, and laser wavelength of 10.6 μm. Thus, the quality of SFPC part was significantly enhanced when the optimum parameters were applied in SLS process. This article provided the main reference value for the choice of the process parameters of the biomass composite.

Study in performance and morphology of polyamide 12 produced by selective laser sintering technology

2018 ◽  
Vol 24 (5) ◽  
pp. 813-820 ◽  
Author(s):  
Junjie Wu ◽  
Xiang Xu ◽  
Zhihao Zhao ◽  
Minjie Wang ◽  
Jie Zhang
Keyword(s):  
Selective Laser Sintering ◽  
Polarized Light ◽  
Chain Scission ◽  
High Energy ◽  
Laser Sintering ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Content Type ◽  
X Ray ◽  
Polyamide 12

Purpose The purpose of this paper is to investigate the effect of selective laser sintering (SLS) method on morphology and performance of polyamide 12. Design/methodology/approach Crystallization behavior is critical to the properties of semi-crystalline polymers. The crystallization condition of SLS process is much different from others. The morphology of polyamide 12 produced by SLS technology was investigated using scanning electron microscopy, polarized light microscopy, differential scanning calorimetry, X-ray diffraction and wide-angle X-ray diffraction. Findings Too low fill laser power brought about bad fusion of powders, while too high energy input resulted in bad performance due to chain scission of macromolecules. There were three types of crystal in the raw powder material, denoted as overgrowth crystal, ring-banded spherulite and normal spherulite. Originality/value In this work, SLS samples with different sintering parameters, as well as compression molding sample for the purpose of comparison, were made to study the morphology and crystal structure of sintered PA12 in detail.

Indirect Selective Laser Sintering of 316L Powder and the Properties of the Parts

2015 ◽  
Vol 775 ◽  
pp. 209-213
Author(s):  
Nai Fei Ren ◽  
Ya Hui Hang ◽  
Yan Zhao ◽  
Qi Yu Yang
Keyword(s):  
Compressive Strength ◽  
Laser Power ◽  
Selective Laser Sintering ◽  
Influence Factors ◽  
Scanning Speed ◽  
Laser Sintering ◽  
Sintering Process ◽  
Range Analysis ◽  
Preheating Temperature ◽  
Molded Parts

During selective laser sintering process, different sintering parameters have great impact on the performance of the molded parts, and the degree of influence is different. Using orthogonal test, indirect sintered 316L stainless steel, the compressive strength and precision of the parts were measured and compared to study the influence of various sintering parameters (laser power, scanning speed, scan spacing, preheating temperature) on sintering. The greater degree of influence factors were got by range analysis. The results show that laser power, scanning speed and scan spacing have greater degree of influence on the compressive strength of the parts, and the preheating temperature have less impact. By comparison, the optimum set of parameters was concluded: the laser power is 15W, the scanning speed is 1900mm/s, the scan spacing is 0.125mm, and the preheating temperature is 60°C.

scholarly journals Effects of various processing parameters on the mechanical properties of sisal fiber/PES composites produced via selective laser sintering

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5710-5724
Author(s):  
Aboubaker I. B. Idriss ◽  
Jian Li ◽  
Yangwei Wang ◽  
Yanling Guo ◽  
Elkhawad A. Elfaki
Keyword(s):  
Mechanical Strength ◽  
Laser Power ◽  
Low Cost ◽  
Selective Laser Sintering ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Laser Sintering ◽  
Sisal Fiber ◽  
Preheating Temperature ◽  
Scan Speed

A new type of sustainable material, i.e., a sisal fiber/poly-ether sulfone composite (SFPC), which is energy-efficient, environmentally friendly, and has a low cost, was developed for laser sintering additive manufacturing. This study was performed to explore the effects of the processing parameters on the SFPC composite parts produced via selective laser sintering (SLS). The effects of the laser sintering processing parameters, i.e., the preheating temperature, laser power, and scan speed, were studied. Bending and tensile testing of the SFPC specimens was successfully performed via SLS. The effect of the processing parameters on the SLS in terms of the mechanical strength of the laser-sintered parts was investigated. The results determined that the processing parameters had a significant effect on the mechanical strength of the sintered SFPC parts. When the preheating temperature and laser power were increased in the processing SLS system, the mechanical strength of the sintered SFPC parts was significantly increased. However, the scanning speed had an inverse proportional relationship to the mechanical strength of the SFPC SLS parts.

Direct Fabrication of Bulk Nanostructured Ceramic from Nano-Al2O3 Powders by Selective Laser Sintering

2007 ◽  
Vol 329 ◽  
pp. 613-618 ◽  
Author(s):  
Li Da Shen ◽  
Y.H. Huang ◽  
Zong Jun Tian ◽  
Guo Ran Hua
Keyword(s):  
Selective Laser Sintering ◽  
Laser Sintering ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Technological Parameters ◽  
Bulk Materials ◽  
Al2o3 Ceramic ◽  
X Ray ◽  
Nanostructured Ceramic ◽  
Direct Fabrication

Nanostructured ceramic bulk materials were achieved from nano-Al2O3 ceramic powders via direct selective laser sintering (SLS). SLS as a non-traditional machining technology of Rapid Prototyping was introduced and compared with other ceramic forming technologies. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were applied to analyze the microstructure of the ceramic bulk materials. These results demonstrated that the nano-Al2O3 ceramic powders can be sintered into bulk materials maintained nanostructure with some technological parameters. It was found that the nanostructured ceramic bulk exhibited unique microstructure and was free formed rapidly by this sintering technology.

Selective Laser Sintering of Different Powders of Co-Cr-Mo

2014 ◽  
Vol 802 ◽  
pp. 338-342
Author(s):  
Claudinei dos Santos ◽  
Paula Cipriano da Silva ◽  
Luciane Carvalho de Paula ◽  
Alexandre Fernandes Habibe ◽  
Jefferson Fabrício C. Lins ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Size Distribution ◽  
Cross Section ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

In this work, different commercial Co-Cr-Mo powders were used in selective laser sintering. Commercial powders with particle size distribution between 5 and 50μm were sintered by laser sintering, and characterized. The samples were characterized by X-ray diffraction, indicating Co as the only crystalline phase. Relative density was measured by Archimedes method showing values between 90 and 96% of TD, depending on the powder used. Scanning electron microscopy performed on the cross section of the sintered samples, indicates that the microstructural features are similar, but the surface finish of the samples differ significantly due to the morphology and size distribution of the starting powders used.

Characterization of Commercial Co-Cr-Alloy Powder Used in Selective Laser Sintering

2014 ◽  
Vol 802 ◽  
pp. 329-333
Author(s):  
Claudinei dos Santos ◽  
Paula Cipriano da Silva ◽  
Luciane Carvalho de Paula ◽  
Alexandre Fernandes Habibe ◽  
Jefferson Fabrício C. Lins ◽  
...  
Keyword(s):  
Particle Size ◽  
Selective Laser Sintering ◽  
Microstructural Characterization ◽  
Laser Sintering ◽  
Spherical Particles ◽  
Metal Powders ◽  
X Ray Diffraction ◽  
X Ray ◽  
Present Particle

This paper presents the microstructural characterization of particle systems used in equipment for selective laser sintering. Three distinct commercial metal powders, with chemical composition based on Co-Cr-alloy, were characterized by X-ray diffraction, scanning electron microscopy and particle size distribution. The powders showed regular spherical particles with varying sizes and crystalline phase of Co-solid solution. Different powders present particle size among 55nm and 245 nm. This behavior affects the sinterability of samples submitted to the selective laser sintering.

scholarly journals Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 346
Author(s):  
Sonam Goyal ◽  
Maizatul Shima Shaharun ◽  
Ganaga Suriya Jayabal ◽  
Chong Fai Kait ◽  
Bawadi Abdullah ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalyst Support ◽  
Oxidation Potential ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Optimum Parameters ◽  
Reduction Of Co2 ◽  
Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

scholarly journals Enhancement of Chloroprene/Natural/Butadiene Rubber Nanocomposite Properties Using Organoclays and Their Combination with Carbon Black as Fillers

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1085
Author(s):  
Patricia Castaño-Rivera ◽  
Isabel Calle-Holguín ◽  
Johanna Castaño ◽  
Gustavo Cabrera-Barjas ◽  
Karen Galvez-Garrido ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
High Performance ◽  
Rubber Matrix ◽  
Butadiene Rubber ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rubber Blends ◽  
Ft Ir ◽  
Chloroprene Rubber

Organoclay nanoparticles (Cloisite® C10A, Cloisite® C15) and their combination with carbon black (N330) were studied as fillers in chloroprene/natural/butadiene rubber blends to prepare nanocomposites. The effect of filler type and load on the physical mechanical properties of nanocomposites was determined and correlated with its structure, compatibility and cure properties using Fourier Transformed Infrared (FT-IR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and rheometric analysis. Physical mechanical properties were improved by organoclays at 5–7 phr. Nanocomposites with organoclays exhibited a remarkable increase up to 46% in abrasion resistance. The improvement in properties was attributed to good organoclay dispersion in the rubber matrix and to the compatibility between them and the chloroprene rubber. Carbon black at a 40 phr load was not the optimal concentration to interact with organoclays. The present study confirmed that organoclays can be a reinforcing filler for high performance applications in rubber nanocomposites.

Sign in / Sign up

Export Citation Format

Share Document