共查询到20条相似文献,搜索用时 937 毫秒
1.
Effect of Substrate Temperature on Deposition Behavior of Copper Particles on Substrate Surfaces in the Cold Spray Process 总被引:2,自引:0,他引:2
M. Fukumoto H. Wada K. Tanabe M. Yamada E. Yamaguchi A. Niwa M. Sugimoto M. Izawa 《Journal of Thermal Spray Technology》2007,16(5-6):643-650
The deposition behavior of sprayed individual metallic particles on the substrate surface in the cold spray process was fundamentally
investigated. As a preliminary experiment, pure copper (Cu) particles were sprayed on mirror-polished stainless steel and
aluminum (Al) alloy substrate surfaces. Process parameters that changed systematically were particle diameter, working gas,
gas pressure, gas temperature, and substrate temperature, and the effect of these parameters on the flattening or adhesive
behavior of an individual particle was precisely investigated. Deposition ratio on the substrate surface was also evaluated
using these parameters. From the results obtained, it was quite noticeable that the higher substrate temperature brought about
a higher deposition rate of Cu particles, even under the condition where particles were kept at room temperature. This tendency
was promoted more effectively using helium instead of air or nitrogen as a working gas. Both higher velocity and temperature
of the particles sprayed are the necessary conditions for the higher deposition ratio in the cold spraying. However, instead
of particle heating, substrate heating may bring about the equivalent effect for particle deposition.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
2.
L. C. Erickson T. Troczynski H. M. Hawthorne H. Tai D. Ross 《Journal of Thermal Spray Technology》1999,8(3):421-426
A series of plasma sprayed coatings of controlled microstructure was obtained by spraying three monosize sapphire powders
using an axial injection torch in which the plasma gas composition and nozzle diameter were the only processing parameters
varied. The effects of changes in these parameters on the coating splat morphology, porosity, angular crack distribution,
and hardness are reported. The uniform, dense microstructure and the high hardness of 14 GPa (a level usually only associated
with chromia thermal spray coatings) of the best alumina coatings resulted from using tightly controlled processing conditions
and monodispersed precursor powders. The microstructural quality of plasma sprayed coatings and, hence, the coating properties
can be improved significantly by minimizing variations in processing and raw material parameters.
This paper originally appeared in Thermal Spray: Meeting the Challenges of the 21st Century; Proceedings of the 15th International Thermal Spray Conference, C. Coddet, Ed., ASM International, Materials Park, OH, 1998. This proceedings paper has been extensively reviewed according
to the editorial policy of the Journal of Thermal Spray Technology. 相似文献
3.
4.
Thermal spraying is a widely used technology for industrial applications to provide coatings that improve the surface characteristics.
According to the specificities of processes (APS, VPS, flame, electric arc), any kind of material can be sprayed. Among materials,
ceramic coatings present several interesting aspects such as wear resistance, corrosion protection as well as thermal or electrical
insulation; particularly alumina coatings which appear as the most commonly used. From all spraying processes, atmospheric
plasma spraying (APS) is a rather well-established process but some others can also be used with a lower economical impact
such as the flame technology. The aim of this study was to analyze the alumina coating properties according to the technology
employed such as APS or wire flame spraying using the Rokide™ and the Master Jet? guns. After micrographic analyses by SEM, physical and mechanical properties were measured considering the thermal conductivity
and the hardness.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
5.
Aluminum powder of 99.7 wt.% purity and in the nominal particle size range of −75+15 μm has been sprayed onto a range of substrates
by cold gas dynamic spraying (cold spraying) with helium, at room temperature, as the accelerating gas. The substrates examined
include metals with a range of hardness, polymers, and ceramics. The substrate surfaces had low roughness (R
a < 0.1 μm) before deposition of aluminum in an attempt to separate effects of mechanical bonding from other forms of bonding,
such as chemical or metallurgical bonding. The cross-sectional area of a single track of aluminum sprayed onto the substrate
was taken as a measure of the ease of initiation of deposition, assuming that once a coating had begun to deposit onto a substrate,
its growth would occur at a constant rate regardless of substrate type. It has been shown that initiation of deposition depends
critically upon substrate type. For metals where initiation was not easy, small aluminum particles were deposited preferentially
to large ones (due to their higher impact velocities); these may have acted as an interlayer to promote further building of
the coating. A number of phenomena have been observed following spraying onto various substrates, such as substrate melting,
substrate and particle deformation, and evidence for the formation of a metal-jet (akin to that seen in explosive welding).
Such phenomena have been related to the processes occurring during impact of the particles on the substrate. Generally, initiation
of aluminum deposition was poor for nonmetallic materials (where no metallic bonding between the particle and substrate was
possible) and for very soft metals (in the case of tin, melting of the substrate was observed). Metallic substrates harder
than the aluminum particles generally promoted deposition, although deposition onto aluminum alloy was difficult due to the
presence of a tenacious oxide layer. Initiation was seen to be rapid on hard metallic substrates, even when deformation of
the substrate was not visible.
The original version of this article was published as part of the ASM Proceedings, Thermal Spray 2003: Advancing the Sciences and Applying the Technology, International Thermal Spray Conference (Orlando, FL), May 5–8, 2003, Basil R. Marple and Christian Moreau, Ed., ASM International,
2003. 相似文献
6.
利用光学显微镜、扫描电镜、XRD和硬度计等分析了Cu-Al-Ni合金在冷轧与退火过程中微观组织结构及硬度的变化规律,研究了合金在不同退火温度条件下的软化行为。结果表明,当采用950 ℃保温淬火工艺后,Cu-Al-Ni合金主要由面心立方结构的α相与体心立方结构的β相组成,分布于晶界处的β相对合金硬度的影响作用小。由于位错强化作用的显著增强,合金在冷轧后硬度明显升高,达到270 HV0.5。冷轧态Cu-Al-Ni合金在400 ℃以上温度退火后会发生明显软化现象,软化的主要原因是再结晶反应所引起的位错密度下降。Cu-Al-Ni合金的再结晶温度在300 ℃以上,高于纯铜的再结晶温度,这表明Ni、Al元素的添加有利于提高纯铜再结晶温度,并能改善其高温抗软化性能。 相似文献
7.
超细晶铜在退火与高温变形条件下微观结构的不稳定性研究 总被引:1,自引:0,他引:1
通过差示扫描量热仪(DSC)和显微硬度测试研究了等通道转角挤压(ECAP)制备的超细晶铜在退火条件下的热稳定性和硬度变化, 同时利用扫描电镜电子通道衬度(SEM--ECC)技术和透射电镜(TEM)研究了超细晶铜在室温到300 ℃的温度范围内分别在单向压缩和循环变形后的微观结构变化. 结果表明: 超细晶铜即使在低于再结晶温度退火条件下也会以缓慢渐进的方式发生逐步的再结晶和晶粒粗化, 该结构软化过程通过DSC随退火时间的响应曲线探测不到. 高温压缩下晶粒的粗化行为与应变速率有关, 应变速率越大, 粗化的局部化越明显; 应变速率越小, 更多的晶粒发生整体粗化. 高温循环加载促使晶粒粗化发生得更为显著、均匀, 在粗化的晶粒内可观察到一些典型的位错组态, 如墙结构和胞结构等. 另外, 利用最大晶粒尺度(Dmax)与平均晶粒尺度(Daver)的比值V定量讨论了不同高温变形情况下晶粒粗化的不均匀性. 相似文献
8.
Hongliang Zhao Wenbo Chen Mingwei Wu Rongping Li Xianglei Dong 《Oxidation of Metals》2018,90(1-2):203-215
In this paper, the influence of low oxygen content on the recrystallization of rolled copper foil was studied at different annealing temperatures. The results showed that the recrystallization temperature decreases with an increase in the oxygen content in the foil. Significant transition points occur when the oxygen content exceeds 30 ppm. The oxygen simultaneously affects particle aggregation on the grain boundaries and the dislocation mobility during deformation processes, modulating the recrystallization. A higher oxygen content enables a lower value of the recrystallization temperature, which can in turn effectively enhance plasticity to improve the forming property of the copper foil. It is expected that our investigations on the recrystallization of copper foil can provide a mechanism-based interpretation and technical support for the production optimization and application of copper-based materials. 相似文献
9.
Chang-Jiu Li Guan-Jun Yang Pei-Hu Gao Jian Ma Yu-Yue Wang Cheng-Xin Li 《Journal of Thermal Spray Technology》2007,16(5-6):1011-1020
Nanostructured WC-Co coating was deposited by cold spraying using a nanostructured WC-12Co powder. The critical velocity for
the particle to deposit was measured. The coating microstructure was characterized by X-ray diffraction analysis, scanning
electron microscopy, and transmission electron microscopy. The coating hardness was tested using a Vickers hardness tester.
The deposition behavior of single WC-Co particle was examined. WC particle size was measured for comparison of deposit properties
to that of sintered bulk. The result shows that the nanostructured WC-Co coating can be successfully deposited by cold spraying
using nanostructured powders. The coating exhibited a dense microstructure with full retention of the original nanostructure
in the powder to the coating. The test of microhardness of the coating yielded a value of over 1820 Hv0.3, which is comparable to that of sintered nanostructured WC-Co. The deposition behavior of WC-Co powders as superhard cermet
materials in cold spraying and powder structure effects is discussed.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
10.
Copper (Cu) coating was deposited by cold spraying, and the electrical resistivity of the coating in both directions parallel
and perpendicular to the coating surface was measured to investigate the anisotropy of the coating. Annealing treatment was
applied to the coating to examine its effect on the microstructure and properties of the cold-sprayed Cu coating. The examination
of coating microstructure evidently revealed that the coating was constituted by the flattened particles, and the interfaces
were clearly observed between the deposited particles. The anisotropy in microstructure and electrical resistivity was present
in cold-sprayed Cu coating. The electrical resistivity of the as-sprayed coating was higher than that of Cu bulk. Moreover,
the electrical resistivity along the direction parallel to the coating surface was lower than that along the perpendicular
direction. It was found that annealing treatment led to the enhancement of particle interface bonding and evident recry stallization
of the elongated grains and remarkable grain growth as well. The annealed coating presented equiaxed grain structures similar
to the annealed Cu bulk with particle interfaces almost disappearing under certain annealing conditions. The coalescence of
voids or pores in the coating was clearly observed at high annealing temperatures. Moreover, the annealed coating yielded
an electrical resistivity and microhardness comparable to Cu bulk.
The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and HW International Institute of Welding,
Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany. 相似文献
11.
In cold spraying, bonding is associated with shear instabilities caused by high strain rate deformation during the impact.
It is well known that bonding occurs when the impact velocity of an impacting particle exceeds a critical value. This critical
velocity depends not only on the type of spray material, but also on the powder quality, the particle size, and the particle
impact temperature. Up to now, optimization of cold spraying mainly focused on increasing the particle velocity. The new approach
presented in this contribution demonstrates capabilities to reduce critical velocities by well-tuned powder sizes and particle
impact temperatures. A newly designed temperature control unit was implemented to a conventional cold spray system and various
spray experiments with different powder size cuts were performed to verify results from calculations. Microstructures and
mechanical strength of coatings demonstrate that the coating quality can be significantly improved by using well-tuned powder
sizes and higher process gas temperatures. The presented optimization strategy, using copper as an example, can be transferred
to a variety of spray materials and thus, should boost the development of the cold spray technology with respect to the coating
quality.
This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials
Park, OH, 2006. 相似文献
12.
The morphology of sprayed splats influences the coating adhesion and properties, which are determined by the spraying parameters.
Many studies in this field show that the substrate surface temperature is a very relevant factor for the splat shape: the
hypotheses of substrate surface wettability and contamination or adsorption layer on the surfaces are supported by the fact
that the near-disk-shaped splat can be obtained by increasing the substrate temperature. In this work, a short-duration pulsed
laser was used to ablate the substrate just before powder spraying. This ablation was powerful enough to eliminate the contaminants
on the substrate surface and to improve the adhesion. In this study the analyses of NiAl splat morphology on the polished
TA6V (Ti-6Al-4V) substrate were carried out using laser ablation with different substrate temperatures and different heating
modes: the flame and another laser. Results show that the temperature at which the disk-shaped splat can be obtained decreased
dramatically by laser ablation. Moreover, laser ablation combined with another laser increased the adhesion strength of the
coatings.
The original version of this article was published as part of the ASM Proceedings, Thermal Spray 2003: Advancing the Science and Applying the Technology, International Thermal Spray Conference (Orlando, FL), May 5–8, 2003, Basil R. Marple and Christian Moreau, Ed., ASM International,
2003. 相似文献
13.
通过不同温度的退火试验研究了化学气相沉积高纯钨冷轧后的再结晶行为。结果表明,冷轧钨中形成层状异质结构,提高了材料的应变硬化率,进而提高了塑性,韧脆转变温度降低到200 ℃以下,硬度从沉积态的402 HV0.2提高到547 HV0.2。高温退火后,冷轧钨在1100 ℃发生再结晶,与沉积态钨相比,再结晶温度降低了880 ℃,这是由于低温塑性变形导致材料储存能升高,再结晶驱动力提高,再结晶温度降低。随着退火温度的升高,由于晶粒尺寸的增大,层状异质结构逐渐消失,硬度迅速降低到完全再结晶态的370 HV0.2,而屈服强度从冷轧态的1224 MPa逐渐降低到1800 ℃退火后的558 MPa,但韧脆转变温度仍保持在200 ℃以下。 相似文献
14.
The critical velocity of copper (Cu) particles for deposition in cold spraying was estimated both experimentally and theoretically.
An experimental method is proposed to measure the critical velocity based on the theoretical relationship between deposition
efficiency and critical velocity at different spray angles. A numerical simulation of particle impact deformation is used
to estmate the critical velocity. The theoretical estimation is based on the critical velocity corresponding to the particle
velocity at which impact begins to cause adiabatic shear instability. The experimental deposition was conducted using Cu particles
of different particle sizes, velocities, oxygen contents, and temperatures. The dependency of the critical velocity on particle
temperature was examined. Results show that the critical velocity can be reasonably measured by the proposed test method,
which detects the change of critical velocity with particle temperature and oxygen content. The Cu particles of oxygen content
0.01 wt.% yielded a critical velocity of about 327 m/s. Experiments show that the oxygen content of powder significantly influences
the critical velocity. Variations in oxygen content can explain the large discrepancies in critical velocity that have been
reported by different investigators. Critical velocity is also found to be influenced by particle temperature as well as types
of materials. High particle temperature causes a decrease in critical velocity. This effect is attributed to the thermal softening
at elevated temperatures.
The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and HW International Institute of Welding,
Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany. 相似文献
15.
Hybrid plasma spraying combined with yttrium-aluminum-garnet laser irradiation was studied to obtain optimum zirconia coatings
for thermal barrier use. Zirconia coatings of approximately 150 μm thickness were formed on NiCrAlY bond coated steel substrates
both by means of conventional plasma spraying and hybrid plasma spraying under a variety of conditions. Post-laser irradiation
was also conducted on the plasma as-sprayed coating. The microstructure of each coating was studied and, for some representative
coatings, thermal barrier properties were evaluated by hot erosion and hot oxidation tests. With hybrid spraying, performed
under optimum conditions, it was found that a microstructure with appropriate partial densification and without connected
porosity was formed and that cracks, which are generally produced in the post-laser irradiation treatment, were completely
inhibited. In addition, hybrid spraying formed a smooth coating surface. These microstructural changes resulted in improved
coating properties with regard to hardness, high temperature erosion resistance, and oxidation resistance.
This paper originally appeared in Thermal Spray: Meeting the Challenges of the 21st Century; Proceedings of the 15th International Thermal Spray Conference, C. Coddet, Ed., ASM International, Materials Park, OH, 1998. This proceedings paper has been extensively reviewed according
to the editorial policy of the Journal of Thermal Spray Technology. 相似文献
16.
17.
对一定冷变形00Cr22Ni5Mo3N双相不锈钢再结晶退火后的显微组织进行了研究.结果表明:退火温度从1000℃开始依次增加50℃至1200℃,通过XRD的检测,确定了试样组织由β、γ两相组成,在再结晶退火温度下没有新相产生;经退火处理后得到大小均匀的等轴晶;在较高退火温度下的铁素体的体积分数明显比在较低退火温度下的铁素体的体积分数要高;较低退火温度比较高退火温度的品粒细化的效果要好.在较高退火温度下导致晶粒的长大;不同的再结晶退火温度与试样的显微硬度表现出复杂关系. 相似文献
18.
19.
室温下采用等径弯曲通道变形(Equal Channel Angular Pressing,ECAP)C方式进行了纯铜(99.95%)12道次挤压变形。通过等温和等时退火,研究ECAP变形后铜的退火行为,并研究了等径弯曲通道变形和退火后纯铜的显微硬度和显微结构变化。分析了ECAP应变量、退火时间和退火温度对超细晶铜的再结晶行为、抗软化性能的影响。结果表明:ECAP变形后的超细晶铜在退火过程中,表现出不连续再结晶现象;ECAP降低了铜的热稳定性,变形道次越高再结晶温度越低。退火后稳态晶粒尺寸随变形道次的增加而细化,硬度值随变形道次的增加而增大,回归分析表明,晶粒尺寸与硬度之间的关系符合Hall-Petch公式。 相似文献