Development of Machining Processes for the Use of Multilayer High-Performance Coatings

The development of corrosion- and wear-resistant high-performance coatings is important to improve components of mobile and stationary turbines, aerospace undercarriages, combustion engines, and hydraulic modules. New micro- and nanostructured coating materials and processes to machine these coatings are developed in order to increase the performance of workpieces and components, to enhance durability, and to reduce maintenance and manufacturing costs. At the Institute of Machining Technology (ISF), milling and grinding procedures have been developed for the preparation of the workpiece surface for the subsequent coating process. In contrast to conventional applications, the workpieces are not manufactured with the aim of achieving a minimized resulting surface roughness. Instead of this, a defined and adequate structure has to be generated, providing a good adhesion of the thermal sprayed coating on the workpiece surface. After first coating of the prepared substrates by a High-Velocity-Oxygen-Fuel (HVOF) coating process, the resulting surface topography does not have the required surface quality for a subsequent (Diamond Like Carbon) DLC coating process. In order to generate a more uniform surface structure, the deteriorated surface resulting from the HVOF coating process also has to be processed. Therefore, the application of an adapted grinding process with diamond wheels is used.

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The effects of DLC-coated journal on improving seizure limit and reducing friction under engine oil lubrication

International Journal of Engine Research ◽

10.1177/14680874211012934 ◽

2021 ◽

pp. 146808742110129

Author(s):

Hidemi Ogihara ◽

Takumi Iwata ◽

Yuji Mihara ◽

Makoto Kano

Keyword(s):

Internal Combustion Engines ◽

Fuel Efficiency ◽

Internal Combustion ◽

Engine Oil ◽

Combustion Engines ◽

Main Bearing ◽

Dlc Coating ◽

Lubrication Regime ◽

Mixed Lubrication Regime ◽

Reduce Emissions

Internal combustion engines have been improved markedly in recent years through efforts to conserve resources, reduce emissions and improve fuel efficiency. In this regard, the authors have been working to reduce friction and improve the seizure properties of the crankshaft main journal and main bearing. These mechanical components of internal combustion engines incur large friction losses. In order to reduce friction, journals have been coated with a diamond-like carbon (DLC) coating, which has been reported to reduce friction in the fluid lubrication regime in recent years. Another current issue of journals and bearings is the need to improve seizure resistance. Therefore, these properties were evaluated for material combinations of aluminium alloy bearings and DLC-coated journals, which have low affinity. The results revealed that friction was reduced under a fluid lubrication regime and seizure resistance was improved under a mixed lubrication regime.

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Design aspects of (super)hydrophobic mesh based oil-collecting device with improved efficiency

SN Applied Sciences ◽

10.1007/s42452-021-04179-2 ◽

2021 ◽

Vol 3 (1) ◽

Author(s):

Weikang Xu ◽

Zhentao Zhang ◽

Xiaomei Cai ◽

Yazhen Hong ◽

Tianliang Lin ◽

...

Keyword(s):

3D Printing ◽

Water Surface ◽

High Performance ◽

Oil Spills ◽

Real Life ◽

Oily Wastewater ◽

Coating Materials ◽

The Past ◽

Oil Storage ◽

Future Success

AbstractEffective treatment of frequent oil spills and endless discharged oily wastewater is crucial for the ecosystem and human health. In the past two decades, the collection of oil from water surface has been widely studied through the simple fabrication of superhydrophobic meshes with various coating materials, but little attention is paid to the design aspects of the meshes based oil-collecting device and practical oil collection. Here, 3D-printing devices with different configurations of (super)hydrophobic meshes, circular truncated cone (CTC), cylinder and inverted CTC, and the same inverted cone-shaped structure (below the meshes for temporary oil storage) are investigated. Results demonstrate that the CTC meshes based device especially for an oblate one not only shows higher stability and discharge of the collected oils than previous reports, but also allows floating oils to enter the (super)hydrophobic mesh faster. We anticipate that future success in developing high-performance (super)hydrophobic meshes and the further optimization of the CTC mesh-based device parameters will make our proposed device more practical for the treatment of real-life oil spills.

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Cubic silsesquioxanes as tunable high-performance coating materials

Applied Organometallic Chemistry ◽

10.1002/aoc.3032 ◽

2013 ◽

Vol 27 (11) ◽

pp. 652-659 ◽

Cited By ~ 5

Author(s):

Hyun Wook Ro ◽

Vera Popova ◽

Dave J. Krug ◽

Aaron M. Forster ◽

Richard M. Laine ◽

...

Keyword(s):

High Performance ◽

Coating Materials ◽

High Performance Coating

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Solution to Inverse Problem of Manufacturing by Surface Modification With Controllable Surface Integrity Correlated to Performance: A Case Study of Thermally Sprayed Coatings for Wear Performance

Journal of Tribology ◽

10.1115/1.4036184 ◽

2017 ◽

Vol 139 (6) ◽

Cited By ~ 4

Author(s):

X. P. Zhu ◽

P. C. Du ◽

Y. Meng ◽

M. K. Lei ◽

D. M. Guo

Keyword(s):

Inverse Problem ◽

Surface Modification ◽

Surface Integrity ◽

High Performance ◽

Surface Characteristics ◽

Spray Angle ◽

Functional Surface ◽

Machining Processes ◽

Wear Performance ◽

Surface Features

Inverse problem of manufacturing is studied under a framework of high performance manufacturing of components with functional surface layer, where controllable generation of surface integrity is emphasized due to its pivotal role determining final performance. Surface modification techniques capable of controlling surface integrity are utilized to verify such a framework of manufacturing, by which the surface integrity desired for a high performance can be more effectively achieved as reducing the material and geometry constraints of manufacturing otherwise unobtainable during conventional machining processes. Here, thermal spraying of WC–Ni coatings is employed to coat stainless steel components for water-lubricated wear applications, on which a strategy for direct problem from process to performance is implemented with surface integrity adjustable through spray angle and inert N2 shielding. Subsequently, multiple surface integrity parameters can be evaluated to identify the major ones responsible for wear performance by elucidating the wear mechanism, involving surface features (coating porosity and WC phase retention) and surface characteristics (microhardness, elastic modulus, and toughness). The surface features predominantly determine tribological behaviors of coatings in combination with the surface characteristics that are intrinsically associated with the surface features. Consequently, the spray process with improved N2 shielding is designed according to the desired surface integrity parameters for higher wear resistance. It is demonstrated that the correlations from processes to performance could be fully understood and established via controllable surface integrity, facilitating solution to inverse problem of manufacturing, i.e., realization of a material and geometry integrated manufacturing.

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Cutting Performance of Different Coated Micro End Mills in Machining of Ti-6Al-4V

Micromachines ◽

10.3390/mi9110568 ◽

2018 ◽

Vol 9 (11) ◽

pp. 568 ◽

Cited By ~ 5

Author(s):

Zhiqiang Liang ◽

Peng Gao ◽

Xibin Wang ◽

Shidi Li ◽

Tianfeng Zhou ◽

...

Keyword(s):

Tool Wear ◽

Cutting Edge ◽

Micro Milling ◽

End Mill ◽

Coating Materials ◽

Edge Chipping ◽

Workpiece Surface ◽

Micro End Mill ◽

End Mills ◽

Flank Surface

Tool wear is a significant issue for the application of micro end mills. This can be significantly improved by coating materials on tool surfaces. This paper investigates the effects of different coating materials on tool wear in the micro milling of Ti-6Al-4V. A series of cutting experiments were conducted. The tool wear and workpiece surface morphology were investigated by analyzing the wear of the end flank surface and the total cutting edge. It was found that, without coating, serious tool wear and breakage occurred easily during milling. However, AlTiN-based and AlCrN-based coatings could highly reduce cutting edge chipping and flank wear. Specifically, The AlCrN-based coated mill presented less fracture resistance. For TiN coated micro end mill, only slight cutting edge chipping occurred. Compared with other types of tools, the AlTiN-based coated micro end mill could maximize tool life, bringing about an integrated cutting edges with the smallest surface roughness. In short, the AlTiN-based coating material is recommended for the micro end mill in the machining of Ti-6Al-4V.

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Effects of Ambient Conditions on the Dielectric Properties of Thermally Sprayed Ceramic Coating

Proceedings of the Nordic Insulation Symposium ◽

10.5324/nordis.v0i23.2475 ◽

2018 ◽

Author(s):

M Niittymäki ◽

B. Rotthier ◽

K. Lahti ◽

T. Suhonen ◽

J Metsäjoki

Keyword(s):

Dielectric Properties ◽

Dielectric Breakdown ◽

Breakdown Strength ◽

Thermal Spraying ◽

Ceramic Coatings ◽

Alumina Coating ◽

Ambient Conditions ◽

Coating Materials ◽

Sprayed Coating ◽

Thermally Sprayed

<p>Thermal spraying techniques are used to manufacture insulating coatings especially for demanding applications like fuel cells where normal insulating materials cannot be used. In electrical insulation applications, the mostly used coating materials are aluminum oxide (Al2O3), magnesium oxide (MgO) and magnesium aluminate (MgAl2O4). Dielectric properties of thermally sprayed ceramic coatings are strongly affected by ambient conditions, and in addition to this they are not well documented in the literature. In this paper the effects of environmental conditions on certain dielectric properties of a thermally sprayed coating are studied. DC resistivity as well as permittivity and losses at different frequencies at relative humidities of 20 % and 45 % at temperature of 20 °C, 40 °C and 60 °C will be reported in the paper for Al2O3 samples sprayed using HVOF (High Velocity Oxygen Fuel) technique. DC dielectric breakdown strength is also studied for the HVOF alumina coating at temperature of 20 °C and relative humidity of 20 %. Effects of ambient conditions and coating material composition are also analyzed.</p>

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PLASMA SPRAYED COATING MATERIALS

Advances in Thermal Spraying ◽

10.1016/b978-0-08-031878-3.50058-7 ◽

1986 ◽

pp. 533-541

Author(s):

Ding Chuanxian ◽

Huang Bingtang ◽

Lin Huiling

Keyword(s):

Coating Materials ◽

Sprayed Coating ◽

Plasma Sprayed

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Fabrication of Nano- and Micro-Scale UV Imprint Stamp Using Diamond-Like Carbon Coating Technology

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2006.17994 ◽

2006 ◽

Vol 6 (11) ◽

pp. 3619-3623

Author(s):

Eung-Sug Lee ◽

Jun-Ho Jeong ◽

Ki-Don Kim ◽

Young-Suk Sim ◽

Dae-Geun Choi ◽

...

Keyword(s):

Nanoimprint Lithography ◽

Focused Ion Beam ◽

Ion Beam ◽

Adhesive Layer ◽

Diamond Like Carbon ◽

Coating Process ◽

Ion Beam Lithography ◽

Two Photon ◽

Dlc Coating ◽

Two Photon Polymerization

Two-dimensional (2-D) and three-dimensional (3-D) diamond-like carbon (DLC) stamps for ultraviolet nanoimprint lithography were fabricated with two methods: namely, a DLC coating process, followed by focused ion beam lithography; and two-photon polymerization patterning, followed by nanoscale-thick DLC coating. We used focused ion beam lithography to fabricate 70 nm deep lines with a width of 100 nm, as well as 70 nm deep lines with a width of 150 nm, on 100 nm thick DLC layers coated on quartz substrates. We also used two-photon polymerization patterning and a DLC coating process to successfully fabricate 200 nm wide lines, as well as 3-D rings with a diameter of 1.35 μm and a height of 1.97 μm, and a 3-D cone with a bottom diameter of 2.88 μm and a height of 1.97 μm. The wafers were successfully printed on an UV-NIL using the DLC stamps without an anti-adhesive layer. The correlation between the dimensions of the stamp's features and the corresponding imprinted features was excellent.

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