کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
830672 1470358 2012 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Application of nitriding to electroless nickel–boron coatings: Chemical and structural effects; mechanical characterization; corrosion resistance
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی (عمومی)
پیش نمایش صفحه اول مقاله
Application of nitriding to electroless nickel–boron coatings: Chemical and structural effects; mechanical characterization; corrosion resistance
چکیده انگلیسی

Electroless nickel–boron coatings, synthesized on mild steel, were submitted to nitridation treatments in varying conditions of pressure, temperature and atmosphere composition. One treatment was carried out under a reduced pressure of a nitrogen-based gas, the other under ambient pressure in a ammonia-based atmosphere.The modifications of the samples’ chemistry after those treatments were investigated by ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectroscopy), GD-OES (Glow Discharge-Optical Emission Spectroscopy) and ToF-SIMS (Time of flight-Secondary Ions Mass Spectroscopy) analysis. Their structures and morphology were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical microscopy. The mechanical properties of the samples were investigated by micro- and nanohardness measurements successively on the free surface of the sample and on polished cross-sections; their roughness and resistance to scratch test were measured. Electrochemical corrosion tests were also carried out.The effects of both treatments were then compared: after the treatment carried out under lowered pressure, the coatings are dense, present signs of solution hardening and are characterized by a high hardness (close to 1600 hv100). A combination layer is observable on the samples treated under an ammonia-based atmosphere. This outer layer possesses poorer mechanical properties but the inner layer of the coating presents properties similar to those of vacuum nitrided coatings. The corrosion resistance of the coatings is as good as that of heat treated coatings.

Figure optionsDownload as PowerPoint slideHighlights
► Nitriding of electroless nickel–boron coatings is possible and improves properties.
► Nitrided electroless nickel–boron coatings are harder than heat treated coatings.
► Nitrided electroless nickel–boron coatings have a good scratch test resistance.
► Nitrided Ni–B coatings have a better corrosion resistance than untreated coatings.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials & Design - Volume 39, August 2012, Pages 269–278
نویسندگان
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