Werner Fragner, AMAG Austria Metall AG, Ranshofen, A, René Böhme, Audi AG, Ingolstadt, D, Jens Knaack, AMAG casting GmbH, Ranshofen, A Reciklirana zlitina z majhnim ogljičnim odtisom za varnostne ...komponente Varnostno kritične komponente iz aluminija za uporabo v šasijah so se v preteklosti zaradi zahtev po trdnosti in raztezku izdelovale iz primarnih zlitin. Joshua Bissels , Thomas Greß, Felix Jaruszewski, Pinter Guss GmbH, Deggendorf, D, Georg Fuchs (V), Constantin Bauer, Simon Kammerloher, Hannes Weiss, Wolfram Volk, Technische Universität München, Lehrstuhl für Umformtechnik und Gießereiwesen, Garching, D, Konrad Weiß, RWP GmbH, Roetgen, D Pristopi v tehnologiji litja za izboljšanje učinkovitosti električnih motorjev V povezavi z učinkovitostjo električnih motorjevse večiņa literature osredotoča predvsem na napake med litjem in na proizvodni proces elektropločevine za rotorje asinhronega motorja. Günther Prunner, Voestalpine High Performance Metals International GmbH, Dunaj, A Vpliv orodja za tlačno litje na učinkovitost in storilnost v livarnah V predavanju so predstavljeni: * Trendi in izzivi (vidik livarne in tehnični vidiki) * Pregled globalnoga razvoja na področju tlačnoga litja * Mehanizmi okvar v formah za tlačno litje * Prepoznavanje in ukrepanje/odzivanje na taksne izzive * Vpliv površinskih napak na življenjsko dobo orodij za tlačno litje * Izbira USTREZNIH orodnih jekel za delo v vročem v tlačném litju * Pristop podjetja Voestalpine к tlačnému litju * Uporaba USTREZNEGA jekla, ki je optimizirano za USTREZNO storitev! * Inovacije na področju storitev v tlačném litju * Toplotna in površinska obdelava * Premazi PVD v tlačném litju * Inženiring izdelkov - nova storitev podjetja Voestalpine na področju tlačnega litja Voestalpine se je predstavil kot celoviti ponudnik, ki razume potrebe stranke na področju tlačnega litja in govori njihov jezik, s kombinacijo materiala in storitev pa lahko močno prispeva к povećanju storilnosti v livarnah. 5. Peter Hofer-Hauser, Reinhold Gschwandtner, Österreichisches Gießerei-Institut, Leoben,А Odpornost interno hlajenih jeder za tlačno litje na toplotni šok V zadnjih letih sta gonili procesne tehnike v tlačném litju predvsem dve metodi - mikro nanašanje (micro spraying) in uporaba komponent za forme, izdelane s 3-D tiskanjem. Prav tako je mogoče ciljno odvajanje toplote s hlajenjem blizu površine ter izboljšati tud strok signi kakovost komponent, še posebej lokalno.Vendar pa, še posebej v primeru form in vložkov form, ki se hladijo blizu površine, začnejo razpoke nastajati pri izvrtini za hlajenje in se širijo do površine forme, to pa lahko vodi do uničenja forme ali komponent forme.V predstavljenom príspevku je predstavljen v ÖGI razvilti koncept preskušanja, ki omogoča oceno interno hlajenih jeder za uporabo v tlačném litju ob upoštevanju materiala forme, njenoga stanja toplotne obdelave in vrste hlajenja (konstanten ali časovno nadzorovan protok). To volja še posebej za taljenje/ gretje/odmerjanje, nadzor temperature (v bližini površine), vakuumski sistem in lokalno stiskanje taline med strjevanjem.
This book examines social processes that have contributed to growing pesticide use, with a particular focus on the role governments play in urban aerial pesticide spraying operations. Beyond being ...applied to sparsely populated farmland, pesticides have been increasingly used in densely populated urban environments, and when faced with invasive species, governments have resorted to large-scale aerial pesticide spraying operations in urban areas. This book focuses on New Zealand's 2002–2004 pesticide campaign to eradicate the Painted Apple Moth, which is the largest operation of its kind in world history, whether we consider its duration (29 months), its scope (at its peak the spraying zone was 10,632 hectares/26,272 acres), the number of sprayings that were administered (the pesticide was administered on 60 different days), or the number of people exposed to the spraying (190,000+). This book provides an in-depth understanding of the social processes that contributed to the incursion, why the government sought to eradicate the moth through aerial pesticide spraying, the ideological strategies they used to build and maintain public support, and why those strategies were effective. Urban Aerial Pesticide Spraying Campaigns will be of great interest to students and researchers of pesticides, environmental sociology, environmental history, environmental studies, political ecology, geography, medical sociology, and science and technology studies. The Open Access version of this book, available at http://www.taylorfrancis.com, has been made available under a Creative Commons Attribution-Non Commercial-No Derivatives (CC-BY-NC-ND) 4.0 license.
Thermally sprayed hardmetal coatings have a typical thickness within the range 100–500μm. Thus, thermal spray enables the functionality of hardmetals to be realized on the surface of large parts, ...which cannot be produced by powder metallurgy for technical and economical reasons. This article reviews the different types of thermal spray processes, with particular focus on the high velocity HVOF and HVAF deposition techniques which are of most relevance to the application of hardmetal coatings. Feedstock powder preparation technologies are presented. The majority of hardmetal thermal spray coatings are based either on WC or Cr3C2 or hard phases appearing as a result of their interaction. As an alternative, TiC-based compositions are most intensively studied. Thermal spraying generates significant changes in the hardmetal chemical and phase compositions between the feedstock powder to the sprayed coating. Coating formation and microstructures as well as selected properties, such as hardness, the effect of heat treatments and the oxidation in service, as well as corrosion resistance are discussed. As an example for wear protection applications, abrasion wear resistance is shortly discussed.
This paper is a partly updated and condensed version of the chapter: “Coatings by thermal spray” in the book “Comprehensive Hard Materials”, V.K. Sarin (Editor-in-Chief) & D. Mari & L. Llanes (Vol. Ed.), Vol. 1 (pp. 471–506), Elsevier, 2014.
•Thermal spray as a technology for hardmetal coating preparation is reviewed.•Hardmetal compositions for thermal spray coating preparation are analyzed.•Spray processes and hardmetal feedstock powders are reviewed.•Metallurgical processes during spraying and coating formation are discussed.•Coating microstructures and selected properties are presented.
The aim of this study is to promote significant bond strength with laser surface texturing tools for different coating deposited by spray processes. Pulsed nanosecond laser has been used to improve ...the ultimate adhesion strength of thermal spray coating designed for specific applications, and the full potential of this technology must be further explored. This technology proposes several benefits such as free of grit-particle inclusions, limited affected zone and the interface contact quality. The most important improvement is the coating anchoring in the substrate by laser patterned surface. Adhesion bond strength has been improved and evaluated with the contact area. Fracture mechanic analysis has been studied and it showed that the pattern morphology has an impact on crack propagation. A mixed-mode failure has been defined and chosen to explain adhesion strength improvements for the different applications. Laser surface texturing was performed on light metal alloys substrates before cold spraying of light metal alloys powder, wire-arc metallization and atmospheric plasma spraying of thermal barrier coating without bond coat. This study has highlighted laser potential to enhance adhesion bond strength in the dry deposition field.
•Our study covers surface laser texturing to enhance coating adhesion strength•This paper focuses on anchoring mechanisms induced by prior surface treatments•Adhesion strength and deposition efficiency were increased for different thermal spray processes with laser surface texturing•A short pulsed laser is used with a low power (20W), a high frequency (varying between 10 and 100kHz) and an adapted wavelength (λ=1064μm)•Bonding mechanisms and failures mode are described for conventional and laser treated samples
•MAO + EPS composite coatings were prepared on magensium alloy.•Composite coatings had good binding force with substrates.•Composite coatings had excellent scratch resistance and acid corrosion ...resistance.
Based on the morphological characteristics of the microporous micro arc oxidation (MAO) ceramic coating, a double layer composite coating system was applied on the surface of AZ31 magnesium alloy by MAO plus electrostatic powder spraying (EPS) technique. The Mg sample coated with MAO plus EPS (MAO + EPS) was compared with Mg sample coated by MAO coating or EPS monolayer. The results indicated that the corrosion resistance of AZ31 Mg alloy was significantly improved by MAO + EPS composite coating with the exellent binding force. Furthermore, the corrosion mechanism of three coated Mg alloy was discussed.
Spraying powder characteristics are one of the important parameters that directly affect the microstructure and properties of plasma-sprayed coating. In this research, three types of plasma-sprayed ...yttria partially stabilised zirconia (YSZ) thermal barrier coatings (TBCs) were prepared by atmospheric plasma spraying using micron spherical, micron irregular, and nano-agglomerated spraying powder. The microstructures, and mechanical and thermal shock properties of YSZ TBCs were investigated. The results showed that all three YSZ coatings were relatively dense and mainly composed of t-ZrO2 phase and a small amount of m-ZrO2 phase. Compared with the coating prepared with the micron spherical and irregular spraying powder, the nanostructured coating had higher porosity and bonding strength (9.01% and 59.2 MPa). The thermal conductivity of nanostructured YSZ ceramic coating was 1.08 W·m−1·K−1 at 800 °C, around 10% lower than that of the other two coatings. The coating prepared by nano-agglomerated spraying powder did not begin to exfoliate from the edge of the sample until it had undergone 125 thermal-shock cycles at 1100 °C, which was better than the 72 cycles sustained by the coating with micron spherical powder and the 76 cycles sustained when coating with irregular powder. After 155 thermal-shock cycles at 1100 °C, only a small amount of nanostructured YSZ TBCs were stripped layer-by-layer, while the other two YSZ TBCs had failed due to brittle fracture of the ceramic layer, suggesting that the coating prepared by nano-agglomerated powder exhibited the best thermal shock performance among the three YSZ TBCs at 1100 °C. The main failure mode of plasma-sprayed YSZ TBCs under water-quenching thermal shock at 1100 °C involved separation and exfoliation of the ceramic layer.
•Plasma-sprayed YSZ TBCs with different powder characteristics were prepared.•Nanostructured YSZ TBCs had greater porosity and bond strength among three TBCs.•Nanostructured YSZ TBCs exhibited the best thermal shock performance at 1100 °C.•The failure YSZ TBCs involved the separation and exfoliation of the ceramic layer.
Based on the excellent thermodynamic and service performances of nano-structured coatings, 8YSZ nano-agglomerated spraying powder and its nano-structured thermal barrier coating (TBC) were ...successfully prepared by the integrated application of nanotechnology and atmospheric plasma spraying. The influences of spraying granulation process (solid content of slurry and inlet air temperature) on the spraying powder characteristics and the water quenching-thermal shock cycling behavior at 1050 °C of 8YSZ nano-structured TBC were investigated, respectively. The results showed that the nano-agglomerated powders exhibit apple-like, hollow spheroids with relatively uniform particle size when the spraying granulation process involved a 40% solid content of slurry, a 240 °C inlet air temperature, and a 35 Hz atomizer rotation frequency. The fluidity and apparent density were 57.53 s/50 g and 1.39 g/cm3, respectively. The nano-agglomerated 8YSZ spraying powders met the requirements of plasma-spraying technology. The plasma-sprayed 8YSZ nano-structured coating was composed of a single t-ZrO2 phase, had a layered structure and a certain amount of nanostructures, and presented a special “bimodal microstructure”. The average porosity of the coating was 7.49%. 8YSZ nano-structured TBC failed layer-by-layer after water quenching-thermal shock 264 cycles at 1050 °C. The main reasons for the failure of 8YSZ nano-structured TBC were the large thermal stress and cracks in the substrate caused by the water quench-thermal shock cycle, and the mismatch of thermal expansion between the metal bond coat and the ceramic coat.
•8YSZ nano-agglomerated powder had good fluidity with uniform particle size.•8YSZ nano-structured thermal barrier coating was successfully prepared.•8YSZ coating presented a “bimodal structure” with the presence of nanostructures.•8YSZ nano-structured TBC failed layer by layer after 264 cycles at 1050 °C.
Al–Ti–Ni coatings were fabricated on S355 structural steel using an arc spraying (AS) and laser thermal spraying (LTS), and their electrochemical corrosion performances in 3.5% NaCl, 0.1 M H2SO4 and ...0.1 M NaOH solutions were comparatively investigated. The results show that the obtained coatings are composed of crystalline and amorphous phases, and the metallurgical bonding is formed at the interface of laser thermal sprayed coating. The polarization resistance Rp and charge transfer resistance Rct of laser thermal sprayed coating are higher than those of arc sprayed coating in 3.5% NaCl, 0.1 M H2SO4 and 0.1 M NaOH solutions, while the corrosion current density jcorr is opposite, its electrochemical corrosion resistance is better than the arc sprayed coating. The Rp and Rct of laser thermal sprayed coating in 0.1 M NaOH solution are the highest among the three kinds of solutions, showing the highest electrochemical corrosion resistance.
•The laser thermal sprayed Al-Ti-Ni coating is composed of Al-rich crystal and amorphous phases.•The corrosion resistance of laser thermal sprayed coating is higher than that of arc sprayed coating.•The corrosion resistance in 3.5% NaCl and 0.1 M NaOH solutions is contributed to the hydroxide and oxide films.•The destruction of protective films is the main factor of high corrosion rate in 0.1 M H2SO4 solution.
Thermal barrier coatings (TBCs) play a pivotal role in protecting the hot structures of modern turbine engines in aerospace as well as utility applications. To meet the increasing efficiency of gas ...turbine technology, worldwide research is focused on designing new architecture of TBCs. These TBCs are mainly fabricated by atmospheric plasma spraying (APS) as it is more economical over the electron beam physical vapor deposition (EB-PVD) technology. Notably, bi-layered, multi-layered and functionally graded TBC structures are recognized as favorable designs to obtain adequate coating performance and durability. In this regard, an attempt has been made in this article to highlight the structure, characteristics, limitations and future prospects of bi-layered, multi-layered and functionally graded TBC systems fabricated using plasma spraying and its allied techniques like suspension plasma spray (SPS), solution precursor plasma spray (SPPS) and plasma spray –physical vapor deposition (PS-PVD).
In this study, thermally sprayed Inconel 625 coatings were used to improve the corrosion-wear resistance of 304L stainless steel substrates in saline environments. The tribological behavior of ...various Inconel 625 coatings obtained through flame spraying (F), arc spraying (A), plasma spraying (P), or high-velocity oxygen fuel spraying (H) was evaluated by testing the specimens on a pin-on-disk apparatus with a cup-shaped container that was filled with a 5 wt% NaCl solution or deionized (DI) water. The results indicated that regardless of the testing solution, the corrosion-wear resistance of the Inconel 625 coating specimens was in the order F > A > P > H. Microstructural examination revealed that the oxide within the as-sprayed Inconel 625 coating layer was mainly Cr2O3 and exhibited a higher hardness but lower elastic modulus than the Ni-based matrix. The oxide within the Inconel 625 coating layer is suggested to function as an antiwear phase against the corrosive-wear environment. The high corrosion-wear resistance of the F specimen was attributed to the high oxide content within its coating layer. In addition, all Inconel 625 coatings exhibited higher wear resistance in the 5 wt% NaCl solution than in the DI water, which implied that chloride lubricated the sliding wear, considerably reducing weight loss of the coating after corrosion wear.
•Evaluation of corrosion wear of various thermally sprayed Inconel 625 coatings.•Coatings prepared by flame spray exhibited the highest corrosion-wear resistance.•Oxide improved the corrosion-wear resistance of the coating.•Corrosion-wear resistance was lower in DI water than that in the saline solution.•Chloride lubricated the sliding wear and reduced the weight loss of the coating.
