Carbon Based Coatings for Hermetic Compressor Applications

2014 ◽  
Vol 89 ◽  
pp. 21-30
Author(s):  
Jose Daniel Biasoli de Mello
Keyword(s):  
Surface Engineering ◽  
Low Cost ◽  
Constant Load ◽  
High Wear Resistance ◽  
Tribological Behaviour ◽  
Low Friction ◽  
Dlc Coating ◽  
The Usa ◽  
Hermetic Compressor

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.

scholarly journals The role of marketing in today's enterprises

2014 ◽  
Vol 25 (2) ◽  
pp. 171-194 ◽  
Author(s):  
Jochen Wirtz ◽  
Sven Tuzovic ◽  
Volker G. Kuppelwieser
Keyword(s):  
Firm Performance ◽  
Market Orientation ◽  
Design Methodology ◽  
Low Cost ◽  
Structural Models ◽  
The West ◽  
Marketing Department ◽  
Content Type ◽  
The Usa

Purpose – The purpose of this paper is to explore the role of marketing in today's enterprises and examines the antecedents of the marketing department's influence and its relationship with market orientation and firm performance. Design/methodology/approach – Data were collected from the West (i.e. the USA and Europe) and the East (i.e. Asia). Partial least squares (PLS) was used to estimate structural models. Findings – The findings support the idea that a strong and influential marketing department contributes positively to firm performance. This finding holds for Western and Asian, and for small/medium and large firms alike. Second, the marketing department's influence in a firm depends more on its responsibilities and resources, and less on internal contingency factors (i.e. a firm's competitive strategy or institutional attributes). Third, a marketing department's influence in the West affects firm performance both directly and indirectly (via market orientation). In contrast, this relationship is fully mediated among Eastern firms. Fourth, low-cost strategies enhance the influence of a firm's marketing department in the East, but not in the West. Research limitations/implications – The paper assumes explicitly that a marketing department's influence is an antecedent of its market orientation. While the paper finds support for this link, the paper did not test for dual causality between the constructs. Originality/value – Countering the frequent claim in anecdotal and journalistic work that the role of the marketing department diminishes, the findings show that across different geographic regions and firm sizes, strong marketing departments improve firm performance (especially in the marketing-savvy West), and that they should continue to play an important role in firms.

Alkali treatment and its effect on tribological properties of natrually woven coconut sheath polyester composite

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
I. Siva ◽  
J.T. Winowlin Jappes ◽  
Z. Szakal ◽  
Jacob Sukumaran
Keyword(s):  
Tribological Properties ◽  
Hybrid Composites ◽  
Alkali Treatment ◽  
Low Cost ◽  
Alkaline Treatment ◽  
Natural Fibres ◽  
Tribological Behaviour ◽  
Wear Properties ◽  
Low Friction ◽  
Sem Images

In the recent years natural fibres have drawn great interest for its bio-degradability, low cost and its availability in nature. Among different types of natural fibres, naturally woven coconut sheath fibres are one of the recently explored alternatives for synthetic fibres. These fibres are generally treated with alkali for enhancing mechanical properties and reinforcing characteristics. Tribological applications like gears, cams, bearings, etc. can be benefited from such composites. In most cases chemical treatment are done favouring the structural properties however, their influence on tribological properties are rather not considered. In the current research, hybrid composites (polyester resin with naturally woven coconut sheath (N) and glass fibres (G)) were tested against hardened steel counterface in a pin on disc configuration. Tests were performed at 40 N normal force and 3.5 m/s sliding velocity. From the results all hybrid combinations except (NNN) shows degrading wear properties with the alkaline treatment. The friction properties are modified by having low friction coefficients for all combinations except NGN and GGG hybrids. From the observed SEM images the surface morphology of NNN hybrid significantly differs from the rest of the combinations in both treated and untreated specimens. The partial removal of individual phase (resin) prevails in untreated specimen for which the fibres are highly visible. However, such phenomenon is not dominant in the alkali treated material showing better reinforcing behaviour complimenting low friction properties. The alkali treated specimen has reduced fibre size comparing the untreated specimen which results in low wear resistance. Compromise between friction and wear properties between each other the untreated fibres are best suited for tribological applications. Furthermore, investigations on treatment process and other treatments might have some influence in tribological behaviour.

Synthesis, Properties and Applications of Superhard Amorphous Coatings

1995 ◽  
Vol 383 ◽  
Author(s):  
Michael A. Tamor
Keyword(s):  
Surface Engineering ◽  
Low Cost ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Hard Coatings ◽  
Low Friction ◽  
Capital Costs ◽  
Synthesis Properties ◽  
Improved Performance ◽  
Wear Coatings

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.

scholarly journals In situ Tribo-Fluorination for Oil-Less Hermetic Compressor Applications

2021 ◽  
Vol 7 ◽  
Author(s):  
Gabriel Borges ◽  
Diego Salvaro ◽  
Roberto Binder ◽  
Cristiano Binder ◽  
Aloisio N. Klein ◽  
...  
Keyword(s):  
Surface Engineering ◽  
Current Trend ◽  
Ambient Air ◽  
World Market ◽  
Substrate Material ◽  
Environmental Implications ◽  
Dlc Coating ◽  
Hermetic Compressor ◽  
40 Hz

In the present work, we overview the multidisciplinary development of a regular, lubricated, hermetic compressor which works in an on-off cycle, circular motion, single-speed, many tribological contacts, into an innovative, linear motion, variable displacement, single tribological contact, oil-less hermetic compressor presenting high versatility in terms of refrigerator design, sustainability and improved efficiency. The original approach encompassed the development of new surface engineering procedures applying purpose-oriented phases to soft substrates. Particular emphasis is given to the in situ fluorination of the tribolayer formed in the piston-cylinder tribopair. Although chlorinated halocarbons (CFC) are efficient refrigerants from a thermodynamic point of view, they do have serious environmental implications that have forced the refrigeration industry to switch to more environmentally friendly hydrofluorocarbon (HFC) based refrigerants. The first and most successful alternative to the CFCs was tetrafluorocarbon, particularly tetrafluoroethane (CF3CH2F), aka R134a refrigerant. The current trend to downsizing mechanical systems, smaller clearances, and increased speeds leading to greater energy efficiencies associated with miscibility issues imposing the use of costly, fully synthetic lubricants with the R134a refrigerant gas led to the introduction of a new hermetic compressor design, the Wisemotion®, the first, and until now, unique, oil-free hermetic compressor on the world market. In this context different types of multi-layers, their thickness, substrate material, processing routes, etc., have been studied and optimized. Si-rich hydrogenated DLC (a:C-H) presented enhanced tribological properties when tested under fluorine-rich atmospheres, and semi-industrial scale tests have been carried out to understand this point further. A homemade tribological emulator was developed allowing close-to-real tribopair, atmosphere, and imposed mechanical conditions used in an oil-free commercial hermetic compressor. The tests were carried under different stroke frequencies (5, 20, and 40 Hz) and atmospheres (R134a, ambient air, and argon). Results showed a strong influence of both atmosphere and stroke frequencies. The friction coefficients were significantly lower (~3.8X) for the refrigerant gas atmosphere, attributed to the fluorine and highly disordered graphitic structures rich tribolayers. Under the high frequency (40 Hz), the energy input seems to be a deterrent to the formation of stable tribolayers, and the DLC coating shatters on the first few sliding meters.

scholarly journals Improved Adhesion of the DLC Coating Using HiPIMS with Positive Pulses and Plasma Immersion Pretreatment

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1070
Author(s):  
Iñigo Gómez ◽  
Adrián Claver ◽  
José Antonio Santiago ◽  
Iván Fernandez ◽  
Jose Fernandez Palacio ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Physical Vapor Deposition ◽  
High Wear Resistance ◽  
Low Friction ◽  
New Techniques ◽  
Dlc Coatings ◽  
Dlc Coating ◽  
Chemical Inertness ◽  
Modification Technique ◽  
Tribomechanical Properties

Diamond-like carbon (DLC) coatings are used due to their extraordinary tribomechanical properties, great hardness, high elastic modulus, high wear resistance, low friction coefficient and chemical inertness, which provide them with biocompatibility. Compared to other physical vapor deposition (PVD) coatings of transition nitrides and carbonitrides, DLC has limited adhesion, so it is necessary to develop new techniques to overcome this limitation. This work reports the results of scratch testing for the measurement of adhesion and of tests for wear resistance and nanoindentation in AISI 316L stainless steel coated with a WC:C coating, produced using novel high-power impulse magnetron sputtering (HiPIMS) technology with positive pulses. In addition, the use of a preceding surface modification technique, specifically plasma immersion ion implantation (PIII), was studied with the aim of optimizing the adhesion of the coating. The results show how the coating improved the tribomechanical properties through the use of positive pulse HiPIMS compared to conventional HiPIMS, with an adhesion result that reached critical load values of 48.5 N and a wear coefficient of 3.96 × 10−7 mm3/nm.

scholarly journals Recent Advances in UHMWPE/UHMWPE Nanocomposite/UHMWPE Hybrid Nanocomposite Polymer Coatings for Tribological Applications: A Comprehensive Review

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 608 ◽  
Author(s):  
Mohammed Abdul Samad
Keyword(s):  
Low Cost ◽  
Composite Coatings ◽  
Composite Films ◽  
Polymer Coatings ◽  
High Wear Resistance ◽  
Low Friction ◽  
Corrosion Properties ◽  
Polyether Ether Ketone ◽  
Nanocomposite Polymer ◽  
Wear And Corrosion

In the recent past, polymer coatings have gained the attention of many researchers due to their low cost, their ability to be coated easily on different substrates, low friction and good anti-corrosion properties. Various polymers such as polytetrafluroethylene (PTFE), polyether ether ketone (PEEK), polymethylmethacrylate (PMMA), polyurethane (PU), polyamide (PA), epoxy and ultra-high molecular weight polytheylene (UHMWPE) have been used to develop these coatings to modify the surfaces of different components to protect them from wear and corrosion. However, among all these polymers, UHMWPE stands out as a tribologist’s polymer due to its low friction and high wear resistance. These coatings have found their way into applications ranging from microelectro mechanical systems (MEMS) to demanding tribological applications such as bearings and biomedical applications. Despite its excellent tribological properties, UHMWPE suffers from limitations such as low load bearing capacity and low thermal stability. To overcome these challenges researchers have developed various routes such as developing UHMWPE composite and hybrid composite coatings with several types of nano/micro fillers, developing composite films system and developing dual film systems. The present paper is an effort to summarize these various routes adopted by different researchers to improve the tribological performance of UHMWPE coatings.

Cross-culture outcomes of a brazilian professor Fulbright in the USA

2017 ◽  
Vol 26 (50) ◽  
pp. 115
Author(s):  
Marcelo Da Silva Leite ◽  
Celeste Gaia
Keyword(s):  
Higher Education ◽  
Low Cost ◽  
Cross Culture ◽  
College And University ◽  
Governmental Agencies ◽  
The Past ◽  
University Curriculum ◽  
Fulbright Scholar ◽  
The Usa ◽  
Higher Education Costs

Over the past decade due the expansion of globalization there has been an increasing emphasis on internationalization among faculty, administration and accrediting agencies in the Higher Education.  Although to promote internationalization in the Higher Education, costs are a big challenge, one way to have the international actions with low cost, it is seeking for grants from different governmental agencies and foundations.The Fulbright Scholar program provides a long-standing and externally-funded means for internationalizing college and university curriculum. This article is going to share the perspective   of a Brazilian Fulbright Scholar at an American college and the institution perspective of the Fulbright scholar participation at the College.

EPIZOOTOLOGICAL FEATURES OF MODERN CATTLE LEUKEMIA

1970 ◽  
pp. 53-58
Author(s):  
V. V. Makarov ◽  
D. A. Lozovoy
Keyword(s):  
Dairy Cattle ◽  
Western Europe ◽  
Control Programs ◽  
Foreign Countries ◽  
Negative Order ◽  
Dairy Cattle Breeding ◽  
The Usa ◽  
Epizootic Process ◽  
National Programs

  Enzootic bovine leucosis (EBL) has been known for more than a century and a half. Its occurrence and registration may have historically been associated with intensive breeding of dairy cattle in Western Europe to increase target productivity. It is known that any limiting intervention in the nature of the animal organism is always accompanied by an uncontrolled and unpredictable change in the genotype of a wider range than the required, particularly negative order. In particular, a decrease in the resistance to macroorganisms and the possibility of the new diseases emergence, including infectious ones (for example, immunodeficiencies such as BLAD syndrome of black-motley cattle and stress syndrome in pigs, the occurrence of scrapie and other slow sheep infections). In the last two decades of the last century, in many disadvantaged countries, primarily Western European, national programs for the eradication of EBL have been developed and subsequently successfully implemented. First of all the motivation was the economy of dairy cattle breeding (mainly the extension of productive age, as well as the tightening of requirements in international trade in cattle and bull products, breeding, pricing, etc.). In an analytical article are reviewed the elements of epizootology of EBL in the foreign countries with special attention to the situation in the USA, scenarios of various control programs, and promising methods for assessing the role of infected animals in the epizootic process. A critical assessment of the problem of EBL in the Russian Federation is given, the reasons for the ineffectiveness of against leucosis measures are discussed.

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