Copper is relatively soft metal and its wear and corrosion are considered to be a major factors of degradation of this metal. For this reason, when the higher wear and corrosion properties are needed, surface properties should be improved with different surface treatments. One of these methods is the applying of Ni-P electroless coating due to good mechanical properties, suitable corrosion resistance and its ability of heat treatment on Cu. In this research after the surface preparation of Cu, which included grinding, degreasing and surface activation, the specimens were dipped into commercial electroless nickel bath (SLOTONIP 70A) for 60 minutes. SEM images and the results of the EDS test confirmed the formation of Ni-P electroless coating (with 10.83 wt. % phosphorus) with a spherical structure. Applying the heat treatment increased the hardness from 495 to 880 Vickers. XRD results showed this hardening is due to the formation of Ni crystal and Ni3P phases at this temperature in the coating. The study of wear resistance and corrosion property of coatings was also done using pin-on test and polarization tests, respectively. The results showed that the heat treatment improved the wear resistance of the coating, and the weight loss in the presence of the heat treated coating reduced to 76% due to increasing hardness and roughness of the coating by performing heat treatment. Manuscript profile

Among nanostructured materials, magnetic nanowires have been heeded because of their high shape anisotropy and their easy fabrication methods. Electrochemical deposition on the anodic aluminium oxide (AAO) is one of the best methods to grow different nanowires. In this paper, the AAO was fabricated on the 1100 Al alloy substrate by hard anodizing in 0.3 M oxalic acid solution. Then, a barrier layer thinning process was carried out for the electrodeposition process. A pulsed electrodeposition process was used to fill the nano-pores. According to this method, cobalt nanowires were grown in the nano-holes. Structural, crystalline, and magnetic properties of the samples were evaluated using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM), respectively. The results showed that nanowires have a diameter of 87 nm and crystalline structure with crystalline plates in directions (100), (002), and (110). A coercivity value of 600 Oe was obtained for nanowires, which is several times larger than cobalt bulk. Manuscript profile

Different ceramic coatings can be fabricated on aluminum alloys by the anodizing process. In this process, the nanocells can grow directly from the bottom toward the surface of the coating layer. The ordered porous structure of the anodic aluminum oxide (AAO) layer is a very suitable template for the growth of magnetic nanowires. At this study, one- and two-step anodizing processes were conducted to fabricate the oxide layer in an appropriate acidic electrolyte at three different temperatures (0, -5, -10 ⁰C) and three different voltages (20, 27, 35 V) for 50 min on a 7075 aluminium alloy (7075 AA). The results showed that the samples’ thickness increased with increasing the voltage and decreasing the temperature. The microhardness of samples under different voltages increased with decreasing the temperature. Field emission scanning electron microscopy (FESEM) images were taken from the back and cross-sections of nanocells. The results indicated that the samples which were anodized by the two-step process at -10 ⁰C and 35 V had yielded the best order. Afterward, Zn-Mn ferrite nanowires were produced by electrochemical deposition within the nanocells. X-ray diffraction (XRD) confirmed the formation of the Zn-Mn phase, and FESEM images showed the bulk morphology of nanowires with an appropriate saturation magnetization of about 63.64 emu/g. Manuscript profile

به‌منظور بهبود خواص سطحی و درنتیجه کاربرد بیشتر آلومینیم و آلیاژهای آن در صنایع مختلف بخصوص هوافضا از روش‌های مختلف پوشش دهی استفاده می‌شود. آندایزینگ و آبکاری الکترولس از روش‌های پرکاربرد برای این هدف است. در پژوهش حاضر ابتدا اثر دما و ولتاژ آندایزینگ بر خواص لایه اکسید سطحی آلیاژ آلومینیم 2024 بررسی شد. نتایج نشان داد که با افزایش ولتاژ و کاهش دما، ضخامت و زبری سطح افزایش یافت؛ اما یک ولتاژ بهینه (v45) برای دستیابی به بیشترین سختی در تمامی دماها به دست آمد. مطالعه ضخامت و سختی نمونه بهینه نیز حاکی از افزایش این دو پارامتر با افزایش زمان داشت. بررسی‌های صورت گرفته به‌وسیله میکروسکوپ الکترونی نشرمیدانی (FESEM) نیز نشان داد با کنترل دقیق شرایط آندایزینگ می‌توان به ساختاری با نانو سلول‌های منظم دست‌یافت. انجام آندایزینگ دومرحله‌ای نیز نظم سلول‌های لایه اکسیدی را به‌طور قابل‌ملاحظه‌ای افزایش داد. همچنین بررسی‌های صورت گرفته به‌وسیله میکروسکوپ الکترونی (SEM)، طیف نگار تفکیک انرژی (EDS) و پراش اشعه ایکس (XRD) نشان داد که امکان ایجاد پوشش الکترولس نیکل-فسفر بر آلیاژ آلومینیم آندایز شده به‌خوبی وجود دارد. برای مقایسه رفتار خوردگی پوشش های (Anodic Aluminium Oxid) AAO و هیبریدی AAO/Ni-P با زیرلایه آلومینیمی از روش پلاریزاسیون و برون یابی تافل استفاده شد. نتایج حاکی از مقاومت به خوردگی بالای آلیاژ آلومینیم 2024 در حضور پوشش الکترولس نیکل- فسفر بر آلیاژ آندایز شده می باشد. عملیات حرارتی نمونه‌ها در دماهای مختلف نشان داد که بیشترین سختی پوشش نهایی (1185 ویکرز) در دمای 400 درجه سلسیوس به دست خواهد آمد و زمان عملیات حرارتی در این دما بعد از 75 دقیقه تأثیر چندانی بر سختی نخواهد داشت. Manuscript profile