The application of fine powders in the thermal spray technology represents an innovative approach... more The application of fine powders in the thermal spray technology represents an innovative approach to apply dense and smooth near-net shape coatings on tools with complex geometry. However, this aim can only be achieved, as long as the influence of the handling parameters of the spray process such as the spray angle are sufficiently understood. In this study the influence of the spray angle on the deposition rate as well as on the coating properties (microhardness, roughness and porosity) of HVOF-sprayed, fine-structured coatings is investigated. A fine agglomerated and sintered WC-l2Co powder (agglomerate size: 2-10 pm, WC-particle size: FSS = 400 nm) was used as feedstock material. It has been shown that HVOF spraying of fine powders is less susceptible to an alteration of the spray angle than most other thermal spray processes such as plasma- or arc-spraying. The reduction of the spray angle results in a decrease of the deposition rate, while no significant degradation of the coating properties was found up to 30°. However, at spray angles below 30° the coating strength is negatively affected by the formation of pores and cracks.
The omnipresence and popularity of American consumer products in Japan have triggered an avalanch... more The omnipresence and popularity of American consumer products in Japan have triggered an avalanche of writing shedding light on different aspects of this cross-cultural relationship. Cultural interactions are often accompanied by the term cultural imperialism, a concept that on close scrutiny turns out to be a hasty oversimplification given the contemporary cultural interaction between the U.S. and Japan. The book shows that this assumption of a one-sided transfer is no longer valid. Closely investigating Disney theme parks, sushi, as well as movies, Iris-Aya Laemmerhirt reveals a dialogical exchange between these two nations that has changed the image of Japan in the United States.
The use of fine feedstock powder can extend the feasibility and scope of HVOF coatings to new fie... more The use of fine feedstock powder can extend the feasibility and scope of HVOF coatings to new fields of applications. Especially for the purpose of near-net-shape coatings they facilitate short spraying distances, homogeneous layer morphologies, and smooth coating surfaces. However, the small particle sizes also lead to several challenges. One major issue is the in-flight behavior which is distinctly affected by the low mass and relatively large surface of the particles. In this paper, the in-flight and coating characteristics of WC-CoCr 86-10-4 (-10 +2 μm) were investigated. It was determined that the fine powder feedstock shows a high sensitivity to the gas flow, velocity, and temperature of the spray jet. Because of their low mass inertia, their velocity, for example, is actually influenced by local pressure nodes (shock diamonds) in the supersonic flow. Additionally, the relatively large surface of the particles promotes partial overheating and degradation. Nevertheless, the morphological and mechanical properties of the sprayed layer are hardly affected. In fact, the coatings feature a superior surface roughness, porosity, hardness, and wear resistance.
The omnipresence and popularity of American consumer products in Japan have triggered an avalanch... more The omnipresence and popularity of American consumer products in Japan have triggered an avalanche of writing shedding light on different aspects of this cross-cultural relationship. Cultural interactions are often accompanied by the term cultural imperialism, a concept that on close scrutiny turns out to be a hasty oversimplification given the contemporary cultural interaction between the U.S. and Japan. »Embracing Differences« shows that this assumption of a one-sided transfer is no longer valid. Closely investigating Disney theme parks, sushi, as well as movies, Iris-Aya Laemmerhirt reveals a dialogical exchange between these two nations that has changed the image of Japan in the United States.
... Wolfgang Tillmann, Evelina Vogli, and Benjamin Krebs, Institute of Materials Engineering, Tec... more ... Wolfgang Tillmann, Evelina Vogli, and Benjamin Krebs, Institute of Materials Engineering, Technical University of Dortmund, Leonhard-Euler-Str. ... This behavior is due to a growth of the tan-gential component regarding the substrates surface when ...
ABSTRACT The application of fine powders in thermal spray technology represents an innovative app... more ABSTRACT The application of fine powders in thermal spray technology represents an innovative approach to apply dense and smooth near-net shape coatings on tools with complex geometry. However, this aim can only be achieved as long as the influence of the handling parameters of the spray process, such as the spray angle, is sufficiently understood. In this study, the influence of the spray angle on the deposition rate as well as on the coating properties (microhardness, roughness, and porosity) of HVOF-sprayed, fine-structured coatings are investigated. A fine, agglomerated, and sintered WC-12Co powder (agglomerate size: 2-10 μm, WC-particle Fisher sub-sieve size = 400 nm) was used as feedstock material. It has been shown that HVOF spraying of fine powders is less susceptible to an alteration of the spray angle than most other thermal spray processes such as plasma- or arc-spraying. The reduction of the spray angle results in a decrease in the deposition rate, while no significant degradation of the coating properties is found up to 30°. However, at spray angles below 30° the coating strength is negatively affected by the formation of pores and cracks.
In our world today, different nations and cultures are interconnected via media technologies like... more In our world today, different nations and cultures are interconnected via media technologies like films, television and the Internet. In this context, Sociologist Arjun Appadurai discussed the influence of the media in our global present and suggested a new role for the imagination. Japanese electronic entertainment products and anime cartoons are well known in the U.S. today and Hollywood is shifting away from representing outdated, negative stereotypes in more recent movies like Lost in Translation (2003) and The Last Samurai (2003).
The omnipresence of American brands and consumer products in Japan has triggered an avalanche of ... more The omnipresence of American brands and consumer products in Japan has triggered an avalanche of writing on different aspects of the cross-cultural relationship between Japan and the United States. Whenever cultural interactions between East and West take place, they are frequently accompanied by the term “globalization,” a word often equated with cultural homogenization and “cultural imperialism.” According to the critical theorist John Tomlinson, cultural imperialism is a term that “constrains the negatively marked notions of power, domination, or control.”1 On closer scrutiny, both of these concepts are often hasty oversimplifications, given the contemporary cultural interaction that exists between Japan and the United States. Although economic power relations still play a role, processes of cultural exchange are complex and inconsistent, and they frequently meet resistance. Cultural imperialism, defined by Edward Said as practices and attitudes of a dominating metropolitan cente...
The application of fine powders in the thermal spray technology represents an innovative approach... more The application of fine powders in the thermal spray technology represents an innovative approach to apply dense and smooth near-net shape coatings on tools with complex geometry. However, this aim can only be achieved, as long as the influence of the handling parameters of the spray process such as the spray angle are sufficiently understood. In this study the influence of the spray angle on the deposition rate as well as on the coating properties (microhardness, roughness and porosity) of HVOF-sprayed, fine-structured coatings is investigated. A fine agglomerated and sintered WC-l2Co powder (agglomerate size: 2-10 pm, WC-particle size: FSS = 400 nm) was used as feedstock material. It has been shown that HVOF spraying of fine powders is less susceptible to an alteration of the spray angle than most other thermal spray processes such as plasma- or arc-spraying. The reduction of the spray angle results in a decrease of the deposition rate, while no significant degradation of the coating properties was found up to 30°. However, at spray angles below 30° the coating strength is negatively affected by the formation of pores and cracks.
The omnipresence and popularity of American consumer products in Japan have triggered an avalanch... more The omnipresence and popularity of American consumer products in Japan have triggered an avalanche of writing shedding light on different aspects of this cross-cultural relationship. Cultural interactions are often accompanied by the term cultural imperialism, a concept that on close scrutiny turns out to be a hasty oversimplification given the contemporary cultural interaction between the U.S. and Japan. The book shows that this assumption of a one-sided transfer is no longer valid. Closely investigating Disney theme parks, sushi, as well as movies, Iris-Aya Laemmerhirt reveals a dialogical exchange between these two nations that has changed the image of Japan in the United States.
The use of fine feedstock powder can extend the feasibility and scope of HVOF coatings to new fie... more The use of fine feedstock powder can extend the feasibility and scope of HVOF coatings to new fields of applications. Especially for the purpose of near-net-shape coatings they facilitate short spraying distances, homogeneous layer morphologies, and smooth coating surfaces. However, the small particle sizes also lead to several challenges. One major issue is the in-flight behavior which is distinctly affected by the low mass and relatively large surface of the particles. In this paper, the in-flight and coating characteristics of WC-CoCr 86-10-4 (-10 +2 μm) were investigated. It was determined that the fine powder feedstock shows a high sensitivity to the gas flow, velocity, and temperature of the spray jet. Because of their low mass inertia, their velocity, for example, is actually influenced by local pressure nodes (shock diamonds) in the supersonic flow. Additionally, the relatively large surface of the particles promotes partial overheating and degradation. Nevertheless, the morphological and mechanical properties of the sprayed layer are hardly affected. In fact, the coatings feature a superior surface roughness, porosity, hardness, and wear resistance.
The omnipresence and popularity of American consumer products in Japan have triggered an avalanch... more The omnipresence and popularity of American consumer products in Japan have triggered an avalanche of writing shedding light on different aspects of this cross-cultural relationship. Cultural interactions are often accompanied by the term cultural imperialism, a concept that on close scrutiny turns out to be a hasty oversimplification given the contemporary cultural interaction between the U.S. and Japan. »Embracing Differences« shows that this assumption of a one-sided transfer is no longer valid. Closely investigating Disney theme parks, sushi, as well as movies, Iris-Aya Laemmerhirt reveals a dialogical exchange between these two nations that has changed the image of Japan in the United States.
... Wolfgang Tillmann, Evelina Vogli, and Benjamin Krebs, Institute of Materials Engineering, Tec... more ... Wolfgang Tillmann, Evelina Vogli, and Benjamin Krebs, Institute of Materials Engineering, Technical University of Dortmund, Leonhard-Euler-Str. ... This behavior is due to a growth of the tan-gential component regarding the substrates surface when ...
ABSTRACT The application of fine powders in thermal spray technology represents an innovative app... more ABSTRACT The application of fine powders in thermal spray technology represents an innovative approach to apply dense and smooth near-net shape coatings on tools with complex geometry. However, this aim can only be achieved as long as the influence of the handling parameters of the spray process, such as the spray angle, is sufficiently understood. In this study, the influence of the spray angle on the deposition rate as well as on the coating properties (microhardness, roughness, and porosity) of HVOF-sprayed, fine-structured coatings are investigated. A fine, agglomerated, and sintered WC-12Co powder (agglomerate size: 2-10 μm, WC-particle Fisher sub-sieve size = 400 nm) was used as feedstock material. It has been shown that HVOF spraying of fine powders is less susceptible to an alteration of the spray angle than most other thermal spray processes such as plasma- or arc-spraying. The reduction of the spray angle results in a decrease in the deposition rate, while no significant degradation of the coating properties is found up to 30°. However, at spray angles below 30° the coating strength is negatively affected by the formation of pores and cracks.
In our world today, different nations and cultures are interconnected via media technologies like... more In our world today, different nations and cultures are interconnected via media technologies like films, television and the Internet. In this context, Sociologist Arjun Appadurai discussed the influence of the media in our global present and suggested a new role for the imagination. Japanese electronic entertainment products and anime cartoons are well known in the U.S. today and Hollywood is shifting away from representing outdated, negative stereotypes in more recent movies like Lost in Translation (2003) and The Last Samurai (2003).
The omnipresence of American brands and consumer products in Japan has triggered an avalanche of ... more The omnipresence of American brands and consumer products in Japan has triggered an avalanche of writing on different aspects of the cross-cultural relationship between Japan and the United States. Whenever cultural interactions between East and West take place, they are frequently accompanied by the term “globalization,” a word often equated with cultural homogenization and “cultural imperialism.” According to the critical theorist John Tomlinson, cultural imperialism is a term that “constrains the negatively marked notions of power, domination, or control.”1 On closer scrutiny, both of these concepts are often hasty oversimplifications, given the contemporary cultural interaction that exists between Japan and the United States. Although economic power relations still play a role, processes of cultural exchange are complex and inconsistent, and they frequently meet resistance. Cultural imperialism, defined by Edward Said as practices and attitudes of a dominating metropolitan cente...
Ever since the European discovery of the Hawaiian Islands by Captain James Cook in 1778, this isl... more Ever since the European discovery of the Hawaiian Islands by Captain James Cook in 1778, this island state has been shamelessly exploited economically and reimagined for a wide, mainly white, audience in the media. The island state continues to occupy a unique place in public consciousness, evoking escapist fantasies of dazzling long, sandy beaches, spectacular sunsets, swaying palm trees, and beautiful hula dancers as well as skilled surfers enjoying perfect waves. Numerous novels, TV series, and movies have helped to foster this positive image, at the same time suppressing the dark side of colonial Hawaiian history in favor of a more convenient paradise image. Especially the American movie industry with films such as Waikiki Wedding (1937), Blue Hawaii (1961), Paradise Hawaiian Style (1966) or more recently 50 First Dates (2004) and Forgetting Sarah Marshall (2008) has helped to create Hawai’i as a ‘fantasy-scape’ for a larger audience. The majority of movies set on the island sta...
The minimization of friction and wear is one important goal for the extension of the tool life in... more The minimization of friction and wear is one important goal for the extension of the tool life in forming processes. Therefore, the industry is very interested in new approaches to improve the tribological behavior of tool surfaces. The combination of surface patterns and wear-resistant near-netshape PVD-coatings is very suitable to enhance the tribological properties of tool surfaces. In this study, a substrate composed of high speed steel material S6-5-2 was structured by means of micro milling. Subsequently, a CrCN layer system was deposited using a magnetron sputtering process. The chromium carbonitride coating was deposited as a monolayer- and Cr/CrCN as a multilayer coating system. To compare the mechanical and tribological properties, the developed PVD layer systems were analyzed by nanoindentation, ball-on-disc-tests, scratch-tests as well as scanning electron microscopy.
The use of fine powder feedstock can extend the feasibility and scope of HVOF coatings to new fie... more The use of fine powder feedstock can extend the feasibility and scope of HVOF coatings to new fields of applications. Especially in the purpose of near-net-shape coatings they facilitate short spraying distances, homogeneous layer morphologies, and smooth coating surfaces. However, the small particle sizes also lead to several challenges. One major issue is the in-flight behavior which is distinctly affected by the low mass and the relatively large surface of the particles. In this paper the in-flight and coating characteristics were investigated employing WC‑CoCr 86-10-4 (‑10+2 µm). It was determined that the fine powder feedstock shows a high sensitivity to the gas flow, velocity, and temperature of the spray jet. Because of their low mass inertia, their velocity, for example, is actually influenced by local pressure nodes (shock diamonds) in the supersonic flow. Additionally, the relatively large surface of the particles facilitates partial overheating and degradation. Despite th...
Functional graded coatings offer outstanding thermo-mechanical performance to meet economic deman... more Functional graded coatings offer outstanding thermo-mechanical performance to meet economic demands. Influencing the microstructure formation of layers of the coated tool determines the distribution and transfer of heat from the impact zone into the forming process and largely effects the tool life cycle and microstructure in the surface area of the parts to be formed. With respect to graded coatings, examinations have already shown the application of vertical graded multilayers with adjustable microstructures. By using different grain-sized powder materials and utilizing other thermal spraying methods it is possible to generate either porous or dense coatings according to their requirement profile. In particular, the utilization of different thermal spray methods leads to high costs due to increased setup times. As opposed to methods encompassing separate thermal spray processes, the process parameters for graded coatings generated by an in-situ process need to become attuned to ro...
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