Cold Spray technology and applications

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The Effect of Corrosion on Conventional and
Nanomaterial Copper Cold Spray Surfaces for
Antimicrobial Applications

The Effect of Corrosion on Conventional and Nanomaterial Copper Cold Spray Surfaces for Antimicrobial Applications

right (blue line on the graph). Upon further analysis, differences are seen between the samples as detailed in (Table 2). The Icorr, Ipass, and Ipitt values vary from highest to lowest with the sample order being: bulk Cu, nanomaterial Cu, conventional Cu, and heat- treated samples. This supports the EIS data showing bulk Cu to be the least corrosion resistant, as it has the highest current density, and passivation values. It also has the lowest passivation potential range. Nanomaterial Cu also has a higher corrosion rate than conventional Cu, which is expected as the nanoparticles present in the coating provide a greater percentage of grain boundaries for ion diffusion [2]. Bulk Cu performed worse than nanomaterial Cu, in that it had a higher corrosion rate. This may be due to bulk Cu not being manufactured using cold spray technology, which provides denser coatings with minimal oxides and inclusions [2].
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Particle Image Velocimetry (PIV) of Cold Spray of particles in supersonic nozzles

Particle Image Velocimetry (PIV) of Cold Spray of particles in supersonic nozzles

decades, the technology was further developed from a raw method into a more advanced process for complex applications by a rapidly growing number of research groups, at first located in Russia and the United States, but also in several European and Asian Countries, and Australia [3].

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Fundamental Investigation into the Effects of In process Heat Treatment in Cold Spray

Fundamental Investigation into the Effects of In process Heat Treatment in Cold Spray

Cold spray is a technology with great potential for additive manufacturing applications. Due to the high levels of plastic deformation experienced by the powder during the coating process, any deposit will require heat treatment post-spraying to improve ductility and fatigue strength. In extreme cases, the residual stresses from coating can cause delamination or compromise the bond strength when subsequent cold spray layers are deposited. This work details the use of a commercial CO 2 laser cutter to perform a surface heat treatment on single
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Development of a deposition strategy in Cold Spray for Additive Manufacturing to minimize residual stresses

Development of a deposition strategy in Cold Spray for Additive Manufacturing to minimize residual stresses

Cold Spray (CS) is a novel metal deposition technology, which allows for the formation of coating layers in a melt-free manner and is starting to replace existing technologies at industrial level. This CS process is an exciting new spray technology that has the potential to overcome limitations of more traditional thermal spray processes for some important commercial applications. It is possible to rapidly deposit thin or very thick layers of a wide range of metals, and even some composite materials, without melting or vaporization, at or near room temperature, in an ambient air environment [1].
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Evaluation of ColdZyme Mouth Spray against Common Cold in Elderly Care Personnel

Evaluation of ColdZyme Mouth Spray against Common Cold in Elderly Care Personnel

The specific conditions of elderly care are conducive for transmitting infec- tious agents. Consequences for infected staff often include reduced working ca- pacity and absence from work. In general, upper respiratory tract infections ac- counts for the major fraction of all short term sick leave [7] [8]. The conceptual design of this observational study allowed the assessment of ColdZymes benefit in real-life setting, assessing effectiveness and long-term beneficial effect in terms of sick-leave days. ColdZyme® Mouth Spray (Enzymatica AB, Lund, Sweden) is a medical device against common cold, designed to deliver a solution containing primarily glycerol and trypsin to the mouth/ throat. It is intended to reduce the probability of catching a cold and to help shorten duration of a cold by creat- ing/forming a thin protective barrier on the oropharyngeal mucous membrane.
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User Experience of ColdZyme Mouth Spray against Common Cold in Competitive Athletes

User Experience of ColdZyme Mouth Spray against Common Cold in Competitive Athletes

ColdZyme® Mouth Spray (ColdZyme) is intended to reduce the probability of catching a cold and/or can help shorten the duration of a cold, if used at an early stage of the infection, by forming a barrier on the pharyngeal mucous membrane. The user experience of ColdZyme on naturally occurring com- mon cold infections was evaluated in competitive athletes training professio- nally or on an amateur level. Thirteen athletes completed weekly electronic surveys on occurrence of common colds, cold severity and user experience over the course of 3 months. The 13 participants reported in total 15 cold in- cidents with an average duration of 7.4 days. The average cold severity was 31.2 on a visual-analogue scale (VAS) ranging from 0 (mildest possible cold) to 100 (worst possible cold). The overall user satisfaction with ColdZyme was high. 81% of the reported colds were experienced to be milder and/or shorter than usual. None of the participants reported “No effect”. Out of the partici- pants who reported absence of a cold in the previous week, 69% reported a positive answer to the question if ColdZyme had prevented them from catch- ing a cold in the previous week. Conclusion: The present study evaluated prevention and alleviation of naturally occurring common cold in athletes, and demonstrated that ColdZyme may be an easy and practical way for com- petitive athletes to prevent or reduce infections of the common cold virus and corresponding unwanted absence from training and competition. Due to the lack of a comparator group, a placebo effect cannot be excluded.
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An investigation of the cold gas dynamic supersonic spray process particle/flow field.

An investigation of the cold gas dynamic supersonic spray process particle/flow field.

The CGDS process is similar to the High Velocity Oxy-Fuel (HVOF) process [18] in that it uses a DeLaval nozzle to accelerate particles to supersonic speeds. In the HVOF process, however, particles are heated up to a molten or semi-molten state. Compared to HVOF, there are many advantages to CGDS due to the solid nature o f the particles as all drawbacks of melting such as oxidation and thermally-induced residual stresses on both the spray and target material can be avoided [10]. This allows temperature-sensitive materials to be coated [9], Furthermore, the peening effect of the impinging solid particles causes potentially beneficial compressive residual stresses in the deposited material [15]. Due to the accuracy of directing the powder material, masking is virtually unnecessary and complex structures can be achieved [9,10], The feasibility of producing a very dense coating (with no evidence of pores [9]) makes it possible to generate thick coatings and free-standing shapes [2], A wide range of ductile (metallic and polymeric) materials can be successfully cold-sprayed. In addition, non-ductile materials (such as ceramics) can be cold-sprayed as a mixture with a ductile (matrix) material [15], Nano­ phase, inter-metallic and amorphous materials, which are not amenable to conventional thermal spray processes (due to thermal degradation o f the deposit,) can also be sprayed using this technique. Compared to solvent based liquid coatings, cold spray is easy to apply, with fewer hazards and less waste [19], This technique allows for very high deposition rates of the order of 0.6 g/s [20],
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Calculation of the particle velocity in cold spray 
		in the one dimensional non isentropic approach

Calculation of the particle velocity in cold spray in the one dimensional non isentropic approach

Cold gas dynamic spraying (CGDS or cold spray) is a process in which powder particles of spraying material are injected within supersonic gas flow. Particles move at high speed in the gas stream and impact with the substrate material to form a coating [1, 2, 3]. Properties of the deposited coating and the deposition efficiency are determined by the speed and temperature of the particles at the time of impact [4, 5, 6, 7] and by substrate temperature [8, 9]. Carrier gases are accelerated up to supersonic velocities through converging-diverging De Laval nozzles.

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Evaluation of ColdZyme Mouth Spray against Common Cold in Preschool Staff

Evaluation of ColdZyme Mouth Spray against Common Cold in Preschool Staff

The specific conditions of preschools (kindergarten) are conducive for trans- mitting infectious agents. An infected child may easily propagate the virus among adult workers, parents or other contacts [9]. Consequences for infected staff often include reduced working capacity and absence from work. The objec- tive of this study was to evaluate whether a medical device, ColdZyme® Mouth Spray (ColdZyme®, Enzymatica AB, Lund, Sweden), could be used to prevent common cold infections in preschool staff, thereby alleviating the economic burden and societal costs associated with sick leave.
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Applications of Technology

Applications of Technology

researchers. A number of people have written books on the subject including Collins & Halverson (2009), Watson (2011), and Foreman & Pace (2008). There has been a great deal of research conducted to investigate technology integration in higher education but less has been published regarding K-12 practices. A few examples of what has been published include Ohlenbusch (2001), Wise, Greenwood, & Davis (2011), and Sheng, Siau, & Nah (2010). Ohlenbusch investigated uses of technology in Texas K-12 classrooms (and then applied it to teacher education). Wise, Greenwood, & Davis investigated technology in New Zealand secondary schools and reported significant use of computers and composition software. But as Sheng, Siau, & Nah report, mobile devices and mobile learning are taking over for traditional computers. The prevalence of smart phones and tablets in schools has led to increased use of mobile applications (apps) in classrooms. It is my experience that many teachers are excited for these resources, but some do not know where or how to begin utilizing mobile apps in the music classroom. Although many teachers appear to be talking about mobile apps, little research has been published regarding app function and selection among K-12 music teachers. The purpose of this study is to investigate what mobile apps
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The Effect of In Process Heat Treatment on the Mechanical Properties of Cold Spray Coatings

The Effect of In Process Heat Treatment on the Mechanical Properties of Cold Spray Coatings

temperatures), and subsequently cooled in order for a single heat treatment cycle. In addition, heat treatment of a whole component is in some cases not possible, for example, when heat treating a component repaired by cold spray with dissimilar materials. Recently, studies have suggested laser annealing as a localised heat treatment process which can potentially improve the mechanical properties of coatings [15,16] and remove work hardening from an Al alloy [17] which is known to increase the ductility of the sprayed material. Laser annealing, and a similar technique using focused IR radiation, were investigated with CS coatings and were shown to decrease the hardness of the materials [18,19]. These rapid heat treatment techniques quickly increase the coating to high temperatures but below that of the melting temperature for a short period of the order of minutes. This method has the additional benefit that the heat treatment can be targeted over the load bearing area of the component and, therefore, not all of the component requires treatment. Hence, this technique is particularly suitable for the manufacture of large components or the repair of damaged components using the CS method. Therefore, this study will expand upon the previous work of the authors to determine the effect of in- process rapid heat treatment on the mechanical properties of hardness, strength and ductility of coatings manufactured using CS.
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COMPUTATIONAL PREDICTION OF COLD SPRAY NOZZLE PER FORMANCE FOR THE DEPOSITION OF TITANIUM

COMPUTATIONAL PREDICTION OF COLD SPRAY NOZZLE PER FORMANCE FOR THE DEPOSITION OF TITANIUM

An alternative to conventional deposition technologies [2] [3] [4] is Cold Spray (CS). This method is free of melting and therefore avoids the detrimental effects of those techniques which operates under high temperature levels [5]. High pressure gas is accelerated in a converging-diverging supersonic nozzle to velocities in the order of 1000m/s. The coating material is injected as powder into the nozzle and accelerated by the gas flow. As the powder particles strike against a substrate placed at a distance from the nozzle exit, they deform plastically and bond with the substrate material.
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The deposition of pure aluminium via cold spray for the corrosion protection of steel

The deposition of pure aluminium via cold spray for the corrosion protection of steel

On the other hand, cold spray (CS) as low- temperature coating process is developed and is still to be more and more employed for the quick realization of a compact coating layer onto different substrate materials. Several material systems have already been coated using CS and generally speaking the suitability of the material used in this process is mostly governed by their deformation properties. Materials with relatively low melting point and lower mechanical strength satisfy this condition and Zn, Al, Cu and their alloys are ideal materials for this purpose [18- 20]; however the deposition of strong metals such as Ti is also possible [21]. Recently, the deposition of diamond was also demonstrated possible using powder that are cladded with a ductile phase [23]. In this context, the aim of the present paper concerns to the development and characterization of cold sprayed protective Al coatings on a non-regular steel surface. The research is carryed out with a twofold purpose: one of them is oriented on the optimization of the deposition route selecting the most appropriate process parameters (i.e. velocity orprotective environment.) and the really applicable layer thickness, while the second one is targeted to investigate how the defects and the imperfections of the substrate influences the coating performance and the corrosion resistance of the material.
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Microstructural evaluation of cold spray deposited WC with subsequent friction stir processing

Microstructural evaluation of cold spray deposited WC with subsequent friction stir processing

Friction Stir Processing (FSP) has been shown to improve the strength, ductility and toughness of both aluminium and steel materials through grain refinement and the even distribution of precipitates within the substrate matrix. This article presents the application of FSP of Cold Spray deposited Tungsten Carbide – Cobalt (WC-Co) of two distinct types, on a series of aluminium substrates. Microstructural investigations of FSP processed samples exhibit interaction between the deposited WC-Co particles and aluminium alloy and show the homogeneous dispersion of deposited particles through the metal matrix. Results show that the dispersion of these particles varies with powder type, FSP parameters and substrate characteristics. A parallel study focusing on the hardness of the FSP generated Metal Matrix Composite (MMC) further demonstrate the potential of combining Cold Spray and FSP technologies to tailor surface properties for specific applications.
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Stormwater Mitigation Analysis Using Roof Spray Technology

Stormwater Mitigation Analysis Using Roof Spray Technology

Assuming that on average 100 gallons of water can be evaporated on a 1000 square feet area in one day [24], a thickness of 0.16 inches is found. This is confirmed through the Matlab code developed for theoretical purposes. That thickness allows for the assumed rate of evaporation, on the area specified. In order to get that thickness, a piping system at the peak of the roof will allow water to flow in an intermittent stream to ensure that the water does not go above this calculated thickness and disrupt the time of evaporation in order to provide optimum evaporation. An intermittent stream also allows the roof to dry out in order to prevent growth of bacteria and other potential issues that could weaken the structural integrity of the roof or require 12 in three sections: the first section will be 1” pipe, the next will be ¾” pipe and the last will be ½” pipe. This will increase the pressure in the pipe the farther down that the water needs to go. Each section of pipe will have 75 holes drilled into the side facing outward to spray the water down the roof. In the first two sections, the holes will have a diameter of 0.08” and to account for a pressure loss the last section will have holes with 0.06” diameter.
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Production of Fruit Juice Powders by Spray Drying Technology

Production of Fruit Juice Powders by Spray Drying Technology

Spray-drying is a unit operation by which a liquid product is atomized in a hot gas current to instantaneously obtain a powder. The spray-drying process has been developed in connection with the manufacture of dried milk. The initial liquid feeding the spray-dryer can be a solution, an emulsion or a suspension (Gharsallaoui et al., 2007). The resulting dried product conforms to powders, granules or agglomerates, the form of which depends upon the physical and chemical properties of the feed and the dryer design and operation (Filkova et al., 2007). The characteristics of spray-dried fruit juice and pulp powders depends on spray-drying conditions including concentration of drying aid used, inlet air temperature, feed flow rate, feed characteristics etc. (Chegini et al., 2008). Spray-dryers come in different forms/patterns including cocurrent, counter current and mixed-flow. Cocurrent spray-dryers (where the feed droplets travel in the same direction as that of the drying gas flow) are most common and widely used dryers when compared to other systems (Zbicinski et al., 2002).
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Cold atom interferometers and their applications in precision measurements

Cold atom interferometers and their applications in precision measurements

chamber. To improve the sensitivity of an atom inter- ferometer, either a large loop area or low velocity of atoms is needed. The average velocity of a cold atom prepared in MOT is several meters per second, thus cold matter wave interferometers possess potential in integra- tion over their thermal atomic beam counterparts when they are used as precise inertial sensors. Dual loop con- figuration was adopted in the cold atom gyroscope [8] for eliminating the common model noise. Attention has also been paid to space application of cold atom Sagnac interferometers [9]. Meanwhile, various interference ef- fects [10, 11] with ultracold atoms could also be used in atom interferometers. In this paper we report our labora- tory prototype of a laser-cooled 85 Rb atom interferom- eter [14, 15]. Different from cold atom interferometers of other groups, this atom interferometer is in a hori- zontal configuration; cold atoms are pushed horizontally from trap chamber to interaction chamber. We describe the technical treatments including manipulations of cold atoms, Raman laser beams, Rabi oscillation, stimulated Raman transitions, and optical pumping. Details are given to the demonstration of Mach–Zehnder interfer- ometer, Ramsey–Bord` e interferometer, and the precision measurements of magnetic fields using the atom interfer- ometer [16, 17].
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A QBD APPROACH IN SPRAY DRIED SOLID DISPERSION TECHNOLOGY

A QBD APPROACH IN SPRAY DRIED SOLID DISPERSION TECHNOLOGY

Spray drying is a time-tested manufacturing process for amorphous solid dispersion of poorly water soluble drugs. The understanding on the influence of various formulation and process parameters on the molecular to particulate/bulk level properties of spray dried dispersions is the current need in this field. Spray drying process involves interactions between various formulation variables (like feed concentration, solvent type, type of polymer) and process conditions (drying gas flow rate, feed rate, outlet temperature, atomization rate) which can significantly influence the particle characteristics (yield, particle size, residual solvent content, flow property, surface area and release profile) of the solid dispersion. Thus the implementation of QbD approach in the drying of feed solution containing poorly water soluble API, polymer and additives can result in the robust process development and subsequent scale up with the desired product properties as per predefined objectives.
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Particle in flight velocity and dispersion measurements at increasing particle feed rates in Cold Spray

Particle in flight velocity and dispersion measurements at increasing particle feed rates in Cold Spray

Cold Spray (CS) is a coating manufacturing process, in which a feedstock powder is deposited onto a substrate by means of high velocity impacts and solid state deformation. As the process makes use of the high kinetic energy of the particles obtained from a supersonic process gas rather than their thermal energy, it allows for very low temperature levels compared to other coating technologies. It eliminates or minimizes the disadvantages of melting and hence it provides a possibility to coat oxidisation-sensitive materials and material combinations with different melting temperatures [1][2]. It is generally accepted that for deposition to occur a critical impact velocity must be crossed. This represents a threshold value that makes the particle acceleration a critical aspect of the technology [3][4]. Each material combination is characterized by a specific critical speed level. Both experimental and numerical studies on the two-phase nozzle flow were conducted in the past decades, yielding to the main parameters for gas and particulate acceleration. Primarily, the gas stagnation pressure and temperature [5][6], the gas species [7][8] and the powder injection conditions [9][10] are important. Another critical parameter is the particle material and size, as the larger and heavier particles are the less susceptible to the flow, having a much higher characteristic reaction time [11][12][13], whereas the particle shape is connected to the drag coefficient [14][15]. With the objective of analysing the gas and particle dynamics, different optical measurement techniques were employed in CS. Schlieren photography was frequently used to visualise the flow features. Only resolving the density gradients of the gas phase however impedes quantification of the velocity and particle motion. Therefore, non-intrusive velocity measurement techniques were used, firstly by Gilmore et al. [16]
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Fabrication and microstrain evolution of Al TiB2 composite coating by cold spray deposition

Fabrication and microstrain evolution of Al TiB2 composite coating by cold spray deposition

Aluminium matrix composites (AMCs) have emerged as high performance structural materials for a wide range of applications in aerospace, automotive and transportation industries because of their improved strength, modulus and enhanced wear resistance compared to unreinforced bulk alloys. 1-3 Ceramic reinforced aluminium matrix composites is of particular interest due to their tribological, wear, creep and fatigue properties can be tailored to meet specific requirements by controlling the volume fraction, particle size and distribution of the reinforcing particles in the aluminium matrix. 4-7 Conventional ceramic particles, such as carbides, oxides, nitrides and borides, are widely used to reinforce aluminium alloys. 8-14 Among these reinforcements, more recently, titanium diboride (TiB 2 )
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