Nanostructured coatings produced by plasma spraying
| Project/Area Number |
11650741
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | Osaka University |
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Principal Investigator |
MURAKAMI Kenji ISIR Osaka University Lecturer, 産業科学研究所, 講師 (60112067)
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| Co-Investigator(Kenkyū-buntansha) |
OTA Ken'ichi ISIR Osaka University Research Associate, 産業科学研究所, 助手 (10150351)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1999: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | nanocrystal / boride / plasma spray / iron alloys / coating / mechanical properties / structure / 急速凝固 / 複合粉末 / ポライド |
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| Research Abstract |
Atomized Fe-18mass%Cr-2mass%B alloy powder is low-pressure plasma sprayed onto steel substrates to produce high performance coatings having very fine boride precipitates. The substrate is either water cooled or not cooled. In the latter case, the substrate temperature is 1133K or 1293K depending on the condition of the substrate preheating. The structures and the mechanical properties of the coatings are examined. The results obtained are as follows.
(1) Structures of the coatings :
The coating formed on the water-cooled substrate consists of an amorphous phase and ferrite. The amorphous phase decomposes on heat treatment at 1073K to form non-equilibrium Fe_3B, and (Cr, Fe)_2B appears at higher heat treatment temperatures. In the case of spraying using preheated substrates, the constituents of the coatings are ferrite and (Cr, Fe)_2B of submicrometer size. As the substrate temperature during spraying becomes higher, the cohesion between flattened particles composing the coatings increases and the porosity of the coatings decreases.
(2) Properties of the coatings :
While the coating on the water-cooled substrate has a high hardness, its tensile strength is not so high and is about 0.67GPa. The harness decreases in the case of the coatings on preheated substrates due to the disappearance of the amorphous phase. The tensile strength of these coatings is as high as 1.4GPa, which is attributed to the dispersion of very fine boride precipitates and to the improved cohesion between the flattened particles. When this coating is heat treated at 1473K, the boride particles coarsen to a size of about 0.9μm and the coating softens. This coating, however, has a tensile strength of 0.9GPa with the elongation of about 10% and the best wear resistance in the present work.
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Report
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Research Products
(4 results)
