scholarly journals Hard Quasicrystalline Coatings Deposited by HVOF Thermal Spray to Reduce Ice Accretion in Aero-Structures Components

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 290
Author(s):  
J. Mora ◽  
P. García ◽  
R. Muelas ◽  
A. Agüero

Weather hazards, in particular icing conditions, are an important contributing factor in aviation accidents and incidents worldwide. Many different anti-icing strategies are currently being explored to find suitable long-lasting solutions, such as surface engineering, which can contribute to reduce ice accumulation. Quasicrystals (QCs) are metallic materials, but with similar properties to those of ceramic materials, such as low thermal and electrical conductivities, and high hardness. In particular, QCs that have low surface energy are commercially used as coatings to replace polytetrafluoroethylene (PTFE), also known as Teflon, on frying pans, as they do not scratch easily. PTFE exhibits excellent anti-wetting and anti-icing properties and therefore QCs appear as good candidates to be employed as ice-phobic coatings. Al-based QCs have been applied by High Velocity Oxyfuel (HVOF) thermal spray on typically used aeronautic materials, such as Ti and Al alloys, as well as steels. The coatings have been characterized and evaluated, including the measurement of hardness, roughness, wetting properties, ice accretion behavior in an icing wind tunnel (IWT), and ice adhesion by a double lap shear test. The coatings were studied, both as-deposited, as well as after grinding, in order to study the effect of the surface roughness and morphology on the ice accretion and adhesion properties. The QC coating was compared with PTFE and two polyurethane (PU)-based commercial paints, one of them known to have anti-icing properties, and the results indicate an ice accretion reduction relative to these two materials, and ice adhesion lower than bare AA6061-T6, or the PU paint in the ground version of one of the two QCs. Since the QC coatings are hard (GPa Vickers hardness > 5), a durable behavior is expected.

2013 ◽  
Vol 753-755 ◽  
pp. 277-280 ◽  
Author(s):  
Wei Xiang Liu

Nano-ceramic materials had high hardness and wear resistance. Combined with current technology and cost saving, nanostructured coatings technology were carried out, using HVOF ( high velocity oxygen fuel) or plasma spraying technique can obtain high quality ceramic coating on metal substrate. Ceramic coatings produced cracks in the grinding due to grinding surface residual stress. the coatings grinding surface residual stress of engineering ceramics have been researched, grinding surface residual stress in the nanostructured ceramic coatings are being researched. the researches in this field include grinding process modeling, abrasives and grinding parameters, grinding process monitoring and control and realization of the software, the grinding mechanism and grinding damage on the surface, grinding force prediction, on-line detection, grinding on nanocoating material is a multivariable complex process.


2015 ◽  
Vol 1766 ◽  
pp. 29-35 ◽  
Author(s):  
G.Y. Pérez Medina ◽  
M. Padovani ◽  
M. Merlin ◽  
A.F. Miranda Pérez ◽  
F.A. Reyes Valdés

ABSTRACTGas tungsten arc welding-tungsten inert gas (GTAW-TIG) is focused in literature as an alternative choice for joining high strength low alloy steels; this study is performed to compare the differences between gas metal arc welding-metal inert gas (GMAW-MIG) and GTAW welding processes. The aim of this study is to characterize microstructure of dissimilar transformation induced plasticity steels (TRIP) and martensitic welded joints by GMAW and GTAW welding processes. It was found that GMAW process lead to relatively high hardness in the HAZ of TRIP steel, indicating that the resultant microstructure was martensite. In the fusion zone (FZ), a mixture of phases consisting of bainite, ferrite and small areas of martensite were present. Similar phase’s mixtures were found in FZ of GTAW process. The presence of these mixtures of phases did not result in mechanical degradation when the GTAW samples were tested in lap shear tensile testing as the fracture occurred in the heat affected zone. In order to achieve light weight these result are benefits which is applied an autogenous process, where it was shown that without additional weight the out coming welding resulted in a high quality bead with homogeneous mechanical properties and a ductile morphology on the fracture surface. Scanning electron microscopy (SEM) was employed to obtain information about the specimens that provided evidence of ductile morphology.


2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Bondan T Sofyan ◽  
Haposan J Pardede ◽  
Marizki Stefano ◽  
Edi Sofyan

2019 ◽  
Vol 4 (2) ◽  
pp. 277
Author(s):  
Erie Martides ◽  
Candra Dewi Romadhona ◽  
Djoko Hadi Prajitno ◽  
Budi Prawara

Material SS316 seringkali digunakan untuk komponen yang bekerja pada temperatur tinggi dengan resiko mengalami oksidasi yang menyebabkan penurunan sifat material dan umur pakai dari komponen. Deposisi Metal Matrix Composite (MMC) NiCr+Cr3C2+Al2O3 dan NiCr+WC12Co+Al2O3 menggunakan metode High Velocity Oxygen Fuel (HVOF) thermal spray coating dengan parameter konstan dilakukan sebagai proses perlakuan pada permukaan SS316 untuk meningkatkan nilai kekerasan dan ketahanan terhadap oksidasi.  Tujuan penelitian ini adalah untuk mengetahui pengaruh proses oksidasi lapisan MMC pada material substrat SS316. Proses oksidasi dilakukan dengan variasi temperatur 500° dan 600°C, penahanan temperatur selama 6 jam, kemudian diteruskan dengan karakterisasi serta perhitungan laju oksidasi. Hasil penelitian menunjukkan spesimen MMC NiCr+Cr3C2+Al2O3 yang dilakukan proses oksidasi pada suhu 500°C memiliki laju oksidasi terendah yaitu 6,67 x 10-7 gram/mm2 jam. 


Author(s):  
Alakesh Manna ◽  
Amandeep Kundal

Advanced ceramic materials are gradually becoming very important for their superior properties such as high hardness, wear resistance, chemical resistance, and high strength to weight ratio. But machining of advanced ceramic like Al2O3-ceramics is very difficult by any well known and common machining processes. Normally, cleavages and triangular fractures generate when machining of these materials is done by traditional machining methods. It is essential to develop an efficient and accurate machining method for processing advanced ceramic materials. For effective machining of Al2O3-ceramics, a traveling wire electrochemical spark machining (TW-ECSM) setup has been developed. The developed TW-ECSM setup has been utilized to machine Al2O3 ceramic materials and subsequently test results are utilized to analyze the machining performance characteristic. Different SEM photographs show the actual condition of the micro machined surfaces. The practical research analysis and test results on the machining of Al2O3 ceramics by developed TWECSM setup will provide a new guideline to the researchers and manufacturing engineers.


2019 ◽  
Vol 176 ◽  
pp. 107267 ◽  
Author(s):  
Wei Tong ◽  
Dangsheng Xiong ◽  
Nan Wang ◽  
Zhen Wu ◽  
Huangjie Zhou

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 434
Author(s):  
Snehashis Pal ◽  
Zdenka Peršin ◽  
Tomaž Vuherer ◽  
Igor Drstvenšek ◽  
Vanja Kokol

The modification of a metal implant surface with a biomimetic coating of bone-like anisotropic and graded porosity structures to improve its biological anchorage with the surrounding bone tissue at implanting, is still a high challenge. In this paper, we present an innovative way of a gelatin (GEL) dip-coating on Ti-6Al-4V substrates of different square-net surface textures by the unidirectional deep-freezing process at simultaneous cross-linking using carbodiimide chemistry. Different concentrations of GEL solution were used to study the changes in morphology, density, and mechanical properties of the coatings. In addition, the surface free energy and polarity of Ti-6Al-4V substrate surfaces and GEL solutions have been evaluated to assess the wetting properties at the substrate interfaces, and to describe the adhesion of GEL macromolecules with their surfaces, being supported by mechanical pull-out testing. The results indicate that the coating’s morphology depends primarily on the Ti-6Al-4V substrate’s surface texture and second, on the concentration of GEL, which further influences their adhesion properties, orientation, morphological arrangement, as well as compression strength. The substrate with a 300 × 300 μm2 texture resulted in a highly adhered GEL coating with ≥80% porosity, interconnected and well-aligned pores of 75–200 μm, required to stimulate the bone ingrowth, mechanically and histologically.


Author(s):  
Tong Yul Cho ◽  
Jae Hong Yoon ◽  
Kil Su Kim ◽  
K.O. Song ◽  
Y.K. Joo ◽  
...  

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