Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Article
    Characterisation of Electro-Brush Plated Nickel Coatings on P-Type (Zr,ti)co Half-Heusler Thermoelectric Materials for Stable Contact Layers
    (MDPI, 2025) Gurtaran, Mikdat; Zhang, Zhenxue; Li, Xiaoying; Dong, Hanshan
    In this study, a highly conductive nickel (Ni) layer was deposited onto a P-type (Zr,Ti)Co(Sn,Sb) half-Heusler (HH) thermoelectric (TE) material using a low-cost electro-brush plating technique. Before depositing Ni on the TE material, the plating process was optimised on a stainless steel (SS) substrate. An optimal medium-rate deposition voltage of 6V was identified on the SS substrate, with the desired thickness, superior mechanical performance, reduced sheet resistance and surface roughness, and enhanced electrical conductivity. The optimised deposition condition was then applied to the P-type (Zr,Ti)Co(Sn,Sb) material, resulting in a Ni layer that significantly enhanced its electrical and thermal stability. After thermal exposure at 500 degrees C for 10 h, the Ni coating effectively protected the TE surface against oxidation and sublimation, suggesting that the interfacial contact properties of P-type (Zr,Ti)Co(Sn,Sb) TE material can be effectively enhanced by depositing a highly conductive, oxidation-resistant Ni layer using the cost-effective, straightforward electro-brush plating technique.
  • Article
    Protection of N-Type (Ni,Fe)TiSb Half-Heusler Materials Against Static and Cyclic Oxidation Using a Si-Doped Cr Coating
    (Amer Chemical Soc, 2025) Gurtaran, Mikdat; Zhang, Zhenxue; Li, Xiaoying; Dong, Hanshan
    In this study, Cr-Si coatings were deposited on N-type (Ni,Fe)TiSb thermoelectric (TE) materials by using a closed-field unbalanced magnetron sputtering PVD technique. Oxidation behavior was evaluated under both isothermal (static) conditions (500 degrees C for 10 h and 600 degrees C for 50 h) and thermal cycling regimens (500 and 600 degrees C for 10 or 50 1 h cycles). Mass gain, surface morphology, cross-sectional microstructure, elemental distribution, and phase composition were examined by using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Regardless of exposure mode, uncoated samples oxidized severely: a duplex scale formed, consisting of an outer TiO2 layer and a subjacent NiSb-rich zone, accompanied by extensive cracking and delamination. In sharp contrast, the Cr-Si coatings remained thermally stable and highly oxidation-resistant, maintaining the substrate's integrity during both static and cyclic tests. After exposure, coated samples showed negligible mass gain, no discernible morphological change, and no mechanical damage, confirming that the Cr-Si layer markedly enhances thermal durability and prevents surface degradation.