No abstract

In this work, Ni-P coatings are deposited on the steel substrate by electrodeposition from a solution containing nickel sulfate and sodium hypophosphite (NaH 2 PO 2 ). The effect of the current density on the morphology, phase structure, microhardness, and corrosion performance of the Ni-P coatings are studied. Scanning electron microscopy and energy dispersive X-ray analysis and X-ray diffraction are used to study the morphological, composition and phase structure. The corrosion performance of the coatings is evaluated by weight loss, electrochemical impedance spectroscopy and Tafel polarization. Results showed that the morphology of the electrodeposited Ni-P alloys coatings has spherical grains for all the samples, and the Ni 3 P phases are formed all over the microstructure of the coatings. It is observed that the phosphorus content and microhardness are dependent on the current density. The corrosion tests show that 5 A⋅dm −2 current density is the optimal value which gives the best protective coating against corrosion. It also exhibits superior microhardness originated from the higher Ni 3 P amount.

Lubis M, Harahap MB, Ginting MHS, Maysarah S, Gana A. 2018. Short Communication: The effect of ethylene glycol as plasticizer against mechanical properties of bioplastic originated from jackfruit seed starch and cocoa pod husk. Nusantara Bioscience 10: 76-80. The addition of elasticity of bioplastic from jackfruit seed starch reinforced with cacao pod husk was studied using ethylene glycol as plasticizer. This study aimed to investigate the effect of addition of ethylene glycol as plasticizer against mechanical properties of bioplastic from jackfruit seed starch and cacao pod husk. Bioplastic was made by casting method at temperature 88.1 ̊C with ratios of cacao pod husk as fillers and jackfruit seed as starch were 9:1, 8:2, 7:3, 6:4, and 5:5 (w/v). The variations of ethylene glycol were from 0.2 (v/w) to 0.4 (v/w). The result showed that ethylene glycol could increase the mechanical properties of bioplastic. The best condition of bioplastic was achieved at ratio 7:3 in addition of ethylene glycol was 0.2 (v/w) with tensile strength of 15.40 MPa and elongation at break 2.39%. The result of FT-IR analysis indicated that bioplastics consisted of O-H group, C-H group, C=O group and C-O group. The SEM images demonstrated the bioplastic with cacao pod husk as filler and ethylene glycol as plasticizer had the fracture surfaces with the compact structure compared to that bioplastic without fillers.