Kaplan, Erdar; Sukuroglu, Ebru Emine; Cuvalci, Olkan

This paper investigates the tribological effects of composite oxide coatings grown on ZA-27 surfaces under dry sliding condition. Coating processes were conducted using three different electrolytic solutions through micro-arc oxidation (MAO) method. The base electrolytic solution without any particles as additives was labeled as MAO-Coated, whereas electrolytic solution labeled as Coated-A contained graphite particles and Coated-B contained hexagonal boron nitride (h-BN) particles incorporated into base solution. The morphology of each coated samples were analyzed using a Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). The friction and wear tests were conducted using a pin-on-disc tester in order to evaluate the tribological behavior. Results indicated the friction coefficients of both Coated-A and Coated-B samples were lower when compared to that of uncoated ZA-27 alloy. Further comparative studies showed Coated-A samples containing graphite particles resulted in the lowest friction coefficient.

Kaplan, Erdar; Ünker, Faruk; Çuvalcı, Olkan

-

Soykasap, Omer; Karakaya, Sukru; Kaplan, Erdar; Ilarslan, M; Ince, F; Kaynak, O; Basturk, S

Carbon fiber reinforced plastic (CFRP) composite shell reflectors have been developed for space borne antennas due to their light weight, high thermal stability, and high surface accuracy. In order to reduce launch cost and structural mass, compactly folding and self-deployment of the reflector is preferred. In this paper, the full-scale offset reflector with a diameter of 6 m was designed by introducing reinforcements in the central region. After modal analysis was carried out for full-scale reflector model, the suitability of design was determined and 1/4-scaled version was manufactured. The experiments of the demonstrator were conducted for modal analysis, folding, dynamic deployment behavior and surface accuracy. As a result of study, new reflector model was successfully designed with low-mass, manufacturing ease, lower cost and has a monolithic structure, which two opposite edges of the reflector can be rolled toward the center of the reflector for packaging.