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A Ni-P coating with low phosphorus content has been deposited onto an AISI 1020 plain carbon steel. The effect of temperature on the structure of coating was determined by DSC and XRD analysis. To determine the effect of heat treatment on the hardness and wear properties, some of the coated specimens were heat treated at different temperatures as isothermal for 1 h. Pin-on-disc wear tests were carried out on the specimens under loads of 20, 40 and 60 N, respectively. It has been determined that hardness and wear resistance of electroless Ni-P coating increased with the heat treatment. Maximum hardness and wear resistance were obtained for samples heat treated at 400 °C.

Sıcak ekstrüze edilmiş AA7075-Sicp kompozitlerin tribolojik karakteristiklerine ısıl işlemin etkisi Effect of heat treatments on tribological characteristics of hot-extruded AA7075-Sicp composites Yazar(lar) (Author(s)): Ulaş MATİK, Kübra TANATTIBu makaleye şu şekilde atıfta bulunabilirsiniz (To cite to this article): Matik U. ve Tanattı K., "Sıcak ekstrüze edilmiş AA7075-sicp kompozitlerin tribolojik karakteristiklerine ısıl işlemin etkisi", Politeknik Dergisi, 20(4): 807-814, (2017). Politeknik Dergisi, 2017; 20 (4) : 807-814 Journal of Polytechnic, 2017; 20 (4) ÖZToz metal kompaktların sıcak ekstrüzyonu ile üretilen ve farklı oranlarda 32 µm boyutlu SiC partiküller ile takviye edilen AA7075 Al matrisli kompozitlerin mikroyapı, sertlik ve tribolojik performansına T6 ve T73 ısıl işlemlerinin etkisi incelendi. Bu amaçla, soğuk olarak preslenmiş farklı SiC partikül içeriğine sahip AA7075 toz metal kompaktlar 480 °C'de, 12 mm çaplı çubuklar halinde ekstrüze edildi. T6 ve T73 ısıl işlemlerinin uygulandığı ekstrüze edilmiş numunelerin mikroyapı, sertlik ve tribolojik karakteristikleri tarama elektron mikroskobu (SEM), enerji dağınımlı x-ray analizör (EDX), brinell sertlik ve adhesif aşınma test ve analizleri ile incelendi. Deneysel sonuçlar, SiC partikül içeriğinin artmasına bağlı olarak kompozitin sertlik ve aşınma direncinin de arttığını göstermektedir. Ayrıca, T6 ısıl işlemli numunelerin T73 ısıl işlemli numunelere göre daha iyi sertlik, sürtünme ve aşınma performansı gösterdiği tespit edildi.Anahtar Kelimeler: AA7075, kompozit, ekstrüzyon, aşınma, sertlik. Effect of Heat Treatments on Tribological Characteristics of Hot-Extruded AA7075-SiC p Composites ABSTRACTThe effect of T6 and T73 tempers on microstructure, hardness and tribological performance of hot-extruded reinforced with 32 µm sized SiC particles reinforced AA7075 Al matrix composites produced by hot-extrusion of powder metal compacts was investigated. For this purpose, the cold pressed AA7075 powder metal compacts with various SiC contents were extruded into 12 mm rod bars at 480 °C. The microstructure, hardness and tribological characteristics of T6 and T73 tempered samples were examined with scanning electron microscopy (SEM), energy dispersive x-ray analyzer (EDX), brinell hardness and adhesive wear tests. The results showed that the hardness and wear resistance of composites increases depending on the increase of SiC particle content. It was also determined that T6 tempered samples showed better hardness, friction and wear performance compared to T73 tempered samples.

Electroless Ni-B coatability of iron based powder metal compacts  Structure, hardness and tribological properties of electroless Ni-B coating  Corrosion resistance of iron based powder metal compact and electroless Ni-B coating The effect of electroless Ni-B alloy coating on the hardness, friction, wear and corrosion resistance of iron based powder metal (PM) compacts were investigated. For this purpose, iron based PM compacts produced by powder metallurgy method were coated with electroless Ni-B alloy coating after a thin layer electroless Ni-P coating. Electroless Ni-B coated and uncoated PM compacts were characterized with scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and microhardness measurements. Tribological properties were determined using pin-on-disc type tribometer under loads of 10, 20 and 40 N, sliding speed of 1 ms −1 and sliding distance of 1000 m. Corrosion resistance of samples were determined by polarization measurements. The results show that electroless Ni-B coating has an amorphous structure and columnar growth morphology. Microhardness and tribological tests have shown that Ni-B coating improves the wear and friction properties of PM compacts with its high hardness and morphological properties. The electroless Ni-B coating caused a significantly increase in the corrosion resistance of PM compacts.