Synthesis, Properties and Applications of Superhard Amorphous Coatings

1995 ◽  
Vol 383 ◽  
Author(s):  
Michael A. Tamor

ABSTRACTLow-friction/ultralow-wear coatings allow “surface engineering” for improved performance and durability, and enable use of new light weight or low cost materials. The accepted correlation of wear resistance with hardness suggests use of ceramic carbides and nitrides, with diamond being the ultimate anti-wear coating. While any of these may be deposited by chemical vapor deposition, the high cost (due to low deposition rates and high capital costs) and (usually) high deposition temperatures makes CVD coating impractical for cost-sensitive automotive applications. While rarely as hard as their crystalline counterparts, hard amorphous films exhibit similar (and occasionally superior) tribological properties and may be deposited on virtually any material at low cost. The highly nonequilibrium deposition process - conformal plasma reactive ion plating (CP-RIP) - allows tailoring of film properties and exploration of completely new compositions with no crystalline counterparts. Factors controlling the mechanical and optical properties of amorphous hard coatings, and recent progress in their application will be reviewed.

2014 ◽  
Vol 89 ◽  
pp. 21-30
Author(s):  
Jose Daniel Biasoli de Mello

Household refrigeration represents 17.3% of home energy consumption in the USA and 47% in Brazil. This article overviews a multidisciplinary approach to develop a traditional hermetic compressor (oil lubricated, with several rotating parts), into an oil-less, linear motion, innovative compressor, with improved efficiency, versatility and sustainability. This involves the development of surface engineering processes combining purpose-oriented phases applied to soft substrates to achieve high wear resistance and load support and low friction coefficient. Initially, the role of the environment (air, CO2 and R600a) on the tribological behaviour of a commercially available Si-rich multifunctional DLC coating deposited on AISI 1020 steel is illustrated. In sequence, the influence of the thickness of different layers (DLC and CrN) on sliding wear is analysed. Results are presented using an original approach (3D triboscopic maps) for two distinct configurations (increasing load and constant load) and findings are confronted with numerical simulations using Film Doctor®. Finally, a low cost process to obtain a multifunctional coating (different nitrided layers + DLC) is described, which uses a unique thermal cycle reactor capable of coating parts in industrial scale with reduced cost.


2019 ◽  
Vol 891 ◽  
pp. 195-199
Author(s):  
Theerapol Thurakitseree ◽  
Chupong Pakpum

According to their wonderful properties, carbon nanotubes (CNTs) have been well known for decades. The synthesis process and catalyst deposition method have also drawn attention to control the nanotube structure and properties. Sputtering method is then one promising option to grow the nanotubes in mass production. This method is, however, still costly. Here, we have presented a simple low-cost custom-made DC magnetron sputtering for catalyst thin film deposition. Three different metal thin films (Fe, Ni, Cu) deposited on Si substrates have been employed to investigate nanotube production. Prior to deposition of the catalysts, Al was used as supporting layer. (Al/Fe, Al/Ni, Al/Cu). CNTs were grown by chemical vapor deposition process at 800°C. Ethanol was preliminary used as a carbon source. It was found that CNTs could be successfully grown from only Al/Ni catalysts in our system with the diameter of approximately 200 nm, where the rest of samples were not observed. In addition, vertical-aligned CNTs with the thickness of about 10 μm could be obtained when acetylene was replaced instead of ethanol with reducing partial pressure of the feedstock. A large D-band at 1338 cm-1 with broader G-band at 1582 cm-1 from Raman spectra give a rise to multi layers growth of sp2 carbon walls. Such dimension suggests that it is the characteristic of multi-walled carbon nanotubes.


1999 ◽  
Vol 593 ◽  
Author(s):  
M. Lindstam ◽  
M. Boman ◽  
K. Piglmayer

ABSTRACTA novel approach to deposit amorphous carbon from the precursor CH2I2 at low cost and high efficiency is reported. The combination of thermal and quantum photo effects shows new interesting growth behaviour. The radiation of a halogen-lamp was used to heat the substrate material and to split photolytically the precursor molecules above the substrate surface. The deposition process was investigated as a function of lamp power, gas phase partial pressures and substrate materials. The films were analysed by Raman spectroscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray photon spectroscopy, transmission electron microscopy and atomic force microscopy.


2021 ◽  
Author(s):  
Olivia V. Scheibel ◽  
Mustafa Koz ◽  
Dieter M. Scheibel ◽  
Michael Schrlau

Abstract Micropipette-based thermocouples provide the advantage of a high tip diameter-to-length aspect ratio allowing the maintenance of a reference temperature crucial for accurate thermal sensing in microdomains. The research efforts in this field strive to achieve high thermoelectric power (voltage change per unit temperature change) while minimizing the sensing area, a pair of tasks that is by nature contradictory and thus, challenging. Herein, the design and fabrication of a carbon-based micropipette thermal sensor are described. A novel manufacturing method and set of materials are used to overcome the reduction in thermoelectric performance associated with small sensor sizes. A glass micropipette is utilized as a template in a chemical vapor deposition process to form a carbon layer in the lumen of the pipette. This carbon micropipette then serves as a scaffold on which gold and nickel are deposited, enabling the device to function as a thermocouple. This low-cost fabrication process results in a thermocouple with a sub-500 nm tip. The response of the thermocouple was characterized and demonstrated good repeatability in a temperature range of 0 to 60 °C. The unique material selection provided a thermoelectric power of 14.9 µV·K-1, a significant improvement (68%) relative to other micropipette-based thermocouples.


2013 ◽  
Vol 199 ◽  
pp. 170-175 ◽  
Author(s):  
Tomasz Tański ◽  
Krzysztof Labisz ◽  
Krzysztof Lukaszkowicz

With the appliance of the development of modern technologies in the areas of surface engineering and related applications, the definition of the term hard coatings can be extended by the Plasma Assisted Chemical Vapor Deposition (PACVD) method. This is a cost-effective plasma deposition process, which can be used to improve surface layer properties, e.g. hardness and wear resistance of aluminium, but also magnesium alloy parts by creating a resistant thick coating on the component surface. In this paper there have been presented results of the structure and mechanical properties investigations of crystalline diamond-like carbon gradient/monolithic coatings (Ti/DLC/DLC) deposited onto magnesium alloy (Mg-Al) and aluminium alloy (Al-Si-Cu) substrate by Plasma Assisted Chemical Vapor Deposition (PACVD). A thin metallic layer (Ti) was deposited prior to deposition of gradient coatings to improve adhesion. Microstructure investigation was performed using scanning electron microscopy and transmission electron microscopy. Tests of the coatings adhesion to the substrate material were made using the scratch test. As an implication for the practice a new layer sequence can be possible to develop, based on PACVD technique. Wear test were performed using the ball-on-disk method.


1999 ◽  
Vol 121 (04) ◽  
pp. 46-48 ◽  
Author(s):  
John DeGaspari

This article discusses that the Argonne National Laboratory is beginning real-world tests of a carbon-based substance that has set records for low friction. An extremely hard ultralow-friction carbon coating, developed at Argonne National Laboratory in Argonne, IL, may offer a way to address friction and wear. Introduced about a year and a half ago, the new coating is nearly friction less under inert conditions. Argonne is working with three development partners, which have signed three-year cooperative research and development agreements to transfer this technology to industry. Two of the companies are working with engine applications; one is a commercial coater, adapting the near-frictionless material to its coating process. One of Argonne’s partners, Front Edge Technology Inc., an industrial coater in Baldwin Park, CA, is using a plasma-enhanced chemical vapor deposition process with the coating. Potential applications of the coating are in the mechanical drive portion of the engine, in which the reciprocating piston motions are converted into a rotating shaft motion.


2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Jing Wang ◽  
Ming Li ◽  
Fangtai Liu ◽  
Shuiliang Chen

We proposed a self-connected carbon nanofiber design for electrode in microbial bioelectrochemical system. This design was realized by direct growth of carbon nanofibers (CNFs) onto stainless steel (SSM) via a chemical vapor deposition process without addition of any external catalysts. In the CNFs-SSM composite electrode, the SSM acted as the conductive network and ensured efficient substrate and proton transfer, and the CNFs layer served as highly porous habitats for thick biofilm propagation. The current generated by the CNFs-SSM was 200 times higher than the bare SSM under the same experimental conditions. This provided a simple and promising method for preparation of electrode material with high performance and low-cost in bioelectrochemical system.


1995 ◽  
Vol 415 ◽  
Author(s):  
F. Dimeo ◽  
S. Semancik ◽  
R.E. Cavicchi ◽  
J.S. Suehle ◽  
P. Chaparala ◽  
...  

ABSTRACTThe quantitative detection of gas concentrations in mixed atmospheres is becoming increasingly important in manufacturing processing, environmental monitoring, and medical diagnostics. Several conductive oxides, such as SnO2, ZnO, and TiO2, are well known to exhibit changes in resistivity when exposed to various gases at temperatures ranging from 200–500°C. Current discrete devices based on resistive changes such as the Taguchi sensor, however, suffer from certain performance problems, including poor gas detection specificity. Integrated arrays of sensors, fabricated using planar technology, offer a promising solution to these problems, as well as other benefits such as low power consumption and low cost.In this paper, we report the results of using Metalorganic Chemical Vapor Deposition (MOCVD) to fabricate thin films of SnO2 on microhotplate arrays. The studied arrays contain 4 micromachined, suspended elements, each having an integrated resistive heater that produces a rapid thermal rise time ∼3 msec. By separately heating individual elements, we can take advantage of the thermally selective nature of the MOCVD process to limit deposition to these areas, resulting in a maskless deposition process. In addition, these array elements have surface electrical contacts that permit the measurement of the resistance of the thin films during deposition, as well as when they are operated in a gas sensing mode. In situ growth measurements will be reported.


2014 ◽  
Vol 20 (1) ◽  
pp. 15-22
Author(s):  
Meysam Zarchi ◽  
Sharokh Ahangarani ◽  
Maryam Zare Sanjari

The advantages of the application of hard coatings, which are well knownfor cutting tools, are to a much lesser extent explored for casting, extrusion, molding and forming tools. Increasing the lifetime of these tools is an important task in surface engineering because of complex loading conditionsand often complicated tool geometry. The plasma-enhanced chemical vapor deposition (PECVD) technique is well suited to deposit hard coatings onto large dies and moulds. The aim of this study was to discuss deposition processes suitable for coating of the often large three-dimensional molds and dies used in metal forming. Furthermore, results obtained using different hard coatings in industrial applications for several case studies like aluminum pressure die-casting; plastics injection molding and sheet metal forming are presented and discussed. For best coating performance, a careful optimization of both substrate pretreatment and coating deposition is necessary. The plasma-enhanced chemical vapor deposition (PECVD) technique shows advantages for these applications because of the high flexibility in pre-treatment using chemical etching and plasma-nitriding, because of its ability to coat large complexly shaped tools and because of the possibility of deposition of low-chlorine containing low-friction coatings.


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