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71.
高速电弧喷涂镍铝打底层结构与性能研究 总被引:3,自引:0,他引:3
高速电弧喷涂技术是近年来发展起来的新型热喷涂技术,该技术具有优势,高效,低成本等特点,本文实验研究了高速电弧喷涂镍铝打底涂层的组织结构和力学性能,涂层的界面结合强度大于40MPa,显微硬度平均值为210HV,表面粗糙度表征参数Ra值为13.11um,涂层孔隙率为2.26%,涂层主要由镍铝合金和镍,铝氧化物组成,高速电弧喷涂镍铝涂层结合强度高,涂层组织致密,是优良的打底涂层。 相似文献
72.
L. Pawlowski 《Journal of Thermal Spray Technology》1996,5(3):317-334
This paper deals with the surfacing technology of ceramic anilox rolls. The rolls are used in the printing industry to transport
the precisely determined quantity of ink in the flexographic printing machines. The technology of roll surfacing is discussed
by taking the following aspects into account: preparation of the powder to spray the ceramic coating; thermal spraying of
the duplex (bond coating and ceramic top coating); postspray finishing by grinding and polishing; and laser engraving. The
powder used as the top coating of the aniloxes is chromium oxide. This powder might be prepared by such techniques as agglomeration,
fusing, and crushing, etc. The preparation technique influences coating properties, such as microstructure (tested with SEM,
OM, XRD, and XPS), open porosity, microhardness, and modulus of elasticity. Comparison of these properties enables optimum
powder preparation techniques to be found. APS technique is used to coat the anilox rolls. Optimization of the plasma spraying
parameters is discussed. Aniloxes are submitted to the grinding and polishing of the ceramic coating before laser engraving
occurs. The final roughness of the finished coating is discussed in view of an optimum absorption of the laser light energy
at engraving. Possible ways of reducing the spraying time are discussed, and future research toward improving the anilox roll
quality is proposed. 相似文献
73.
Manish Roy 《Journal of Thermal Spray Technology》2002,11(3):393-399
The objective of the present work was to determine the dynamic hardness of WC-Co coatings from the dynamic hardness of the
coating substrate system. It was also the purpose of this work to evaluate the influence of coating composition, coating thickness,
and substrate materials on the dynamic hardness of the coating. To achieve the above-mentioned objectives, WC-12%Co and WC-17%Co
coatings were deposited by detonation spraying on three different substrate materials: mild steel, commercially pure (CP)
aluminum, and CP titanium. The dynamic hardness of the coating/substrate composite was evaluated by a drop weight system.
The dynamic hardness of the coating independent of the substrate was determined from the dynamic hardness of the coating/substrate
composite. 相似文献
74.
This article describes the investigation of a new generation of vacuum plasma sprayed CoNiCrAlY coatings on NiCr20Ti in the
sprayed as well as the laser-treated condition. The aim of the study was the improvement of MCrAlY coating properties by modifying
the microstructure through laser remelting with 5-kW Co2: lasers. Parameter analysis and optimization was carried out for the vacuum plasma spraying process, as well as for the laser
remelting technique. The effect of the laser treatment on microstructure, quality of the coatings, and oxidation as well as
hot gas corrosion behavior are reported. 相似文献
75.
Characterization of YSZ solid oxide fuel cells electrolyte deposited by atmospheric plasma spraying and low pressure plasma spraying 总被引:1,自引:0,他引:1
C. Zhang H. L. Liao W. Y. Li G. Zhang C. Coddet C. Zhang C. J. Li C. X. Li X. J. Ning 《Journal of Thermal Spray Technology》2006,15(4):598-603
Yttria doped zirconia has been widely used as electrolyte materials for solid oxide fuel cells (SOFC). Plasma spraying is
a cost-effective process to deposit YSZ electrolyte. In this study, the 8 mol% Y2O3 stabilized ZrO2 (YSZ) layer was deposited by low pressure plasma spraying (LPPS) and atmospheric plasma spraying (APS) with fused-crushed
and agglomerated powders to examine the effect of spray method and particle size on the electrical conductivity and gas permeability
of YSZ coating. The microstructure of YSZ coating was characterized by scanning electron microscopy and x-ray diffraction
analysis. The results showed that the gas permeability was significantly influenced by powder structure. The gas permeability
of YSZ coating deposited by fused-crushed powder is one order lower in magnitude than that by agglomerated powder. Moreover,
the gas permeability of YSZ deposited by LPPS is lower than that of APS YSZ. The electrical conductivity of the deposits through
thickness direction was measured by potentiostat/galvanostat based on three-electrode assembly approach. The electrical conductivity
of YSZ coating deposited by low pressure plasma spraying with fused-crushed powder of small particle size was 0.043 S cm−1 at 100 °C, which is about 20% higher than that of atmospheric plasma spraying YSZ with the same powder.
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
76.
77.
The effect of plasma spraying power on the structure and mechanical properties of hydroxyapatite deposited onto carbon/carbon composites 总被引:5,自引:0,他引:5
Jin-Ling Sui Mu-Sen Li Yu-Peng Lu Yun-Qiang Bai 《Surface & coatings technology》2005,190(2-3):287-292
This paper deals with the effect of plasma spraying power on hydroxyapatite (HA) coatings on carbon/carbon composites (C/C composites). The microstructure and phase composition of the as-sprayed coatings have been examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The shear strength of the HA coatings–C/C substrates was detected on a RGD-5 tensile testing machine. Results indicate that the melting extent and the shear strength of the coatings were evidently improved with the increasing of spraying power. Moreover, the amount of decomposed phases is increased and the content of crystalline HA of coatings was slightly changed. Observation of fracture surfaces shows that carbon fiber bundles can bond well with HA coatings using 40 kW spraying power. 相似文献
78.
The change in structure and adhesion strength of the interface by heating in air has been investigated for a plasma- sprayed
alumina coating on a ceramic substrate with a 50Ni- 50Cr alloy bond coating. A veined structure composed of NiO, NiCr
2O4, and NiAl2O4 oxides grew from the bond coating into cracks or pores in the top coating and the alumina substrate after heating at 1273
K for 20 h in air. The NiAl2O4 spinel may have formed by the oxidization of nickel, which subsequently reacted with the alumina coating or the substrate.
The mechanism of the penetration of the spinel oxides into the cracks or pores is not clear. The adhesion strength of the
coating is increased to about 15 MPa after heating at 1273 K for 20 h in air, compared to an as- sprayed coating strength
of only 1.5 MPa. 相似文献
79.
Yang Gao Lian-Tong An Cheng-Qi Sun Zhi-Jun Yan 《Journal of Thermal Spray Technology》2004,13(4):521-525
The effects of the composition of plasma gases (Ar-N2, Ar-H2), arc current, and voltage on the temperature and velocity of a low-power (5 kW) plasma torch in the arc field free region
has been investigated using an enthalpy probe. Coatings of Al2O3-13TiO2 were deposited under different conditions. The results show that in the Ar-N2 plasma, the enthalpy, temperature, and velocity change little with arc current and voltage when regulating the nitrogen proportion
in the plasma gas. The hardness of the resulting coatings is 800 to 900 kg/mm2 HV.300. For Ar-H2 plasma, however, increases in the H2 content in the mixture of the gases remarkably enhanced the velocity and heat transfer ability of the plasma jet, with the
result that the coatings showed high hardness up to 1200 HV. 相似文献
80.