Effect of Phase Duty Cycle on the Properties of ZrH1.8 Surface Micro-arc Oxidized Ceramic Layer

doi:10.15541/jim20190578

Abstract

Abstract:

To study the respective growths of micro-arc oxidation (MAO) ceramic coatings under three phase duty cycles of 40%-50%-60%, 50%-60%-40%, and 60%-50%-40%, and to thereby improve the compactness and hydrogen permeation resistance of the MAO ceramic coatings on the surface of zirconium hydride, the zirconium hydride matrix went through MAO treatment under constant voltage in the phosphate electrolyte system. On the one hand, the morphology, phase structure, and thickness of the ceramic coatings were analyzed by using scanning electron microscope (SEM), X-ray diffractometer (XRD), and film thickness meter. On the other hand, the hydrogen permeation resistance of the ceramic coatings under the different phase duty cycle was obtained through a vacuum dehydrogenation experiment. The research results indicate that under three phase duty cycle, the accumulated thickness of zirconium oxide ceramic coatings on the surface of ZrH_1.8 are 162.6, 175.9, and 158.7 μm, respectively; all of the produced MAO ceramic coatings consist of three phases, namely M-ZrO₂, T-ZrO₂, and Zr_0.95Ce_0.05O₂. Phase duty cycle has no significant effect on the phase composition of ceramic coatings. Under the phase duty cycle of 40%-50%-60%, the ceramic coating achieves on the surface of zirconium hydride has the thickness of 162.6 μm and the Permeation Reduction Factor (PRF) value of 12.5, indicating a relatively satisfactory hydrogen permeation resistance.

Key words: micro-arc oxidation, zirconium hydride, duty cycle, ceramic layer

CLC Number:

TQ174

YANG Shaohui, YAN Shufang, LI Shijiang, CHEN Weidong, DU Pei, MA Wen. Effect of Phase Duty Cycle on the Properties of ZrH_1.8 Surface Micro-arc Oxidized Ceramic Layer[J]. Journal of Inorganic Materials, 2020, 35(10): 1112-1116.

Figures/Tables 6

Table 1 Electrical parameters of micro-arc oxidation

No.	Anode voltage/V	Cathode voltage/V	Frequency/ Hz	Duty cycle
Ⅰ	350	120	100	40%-50%-60%
Ⅱ	350	120	100	50%-60%-40%
Ⅲ	350	120	100	60%-50%-40%

Fig. 1 Forward current (a) and forward resistance (b) changed with time under different phase duty cycle modes

Fig. 2 Micromorphology of ZrH1.8 micro-arc oxidation ceramic layer under different phase duty cycles (a) 40%-50%-60%; (b) 50%-60%-40%; (c) 60%-50%-40%

Fig. 3 Cross-micromorphology of ZrH1.8 micro-arc oxidation ceramic layers under different phase duty cycle modes (a) 40%-50%-60%; (b) 50%-60%-40%; (c) 60%-50%-40%

Fig. 4 XRD patterns of ZrH1.8 surface ceramic layers under different phase duty cycle modes

Table 2 Thicknesses and permeation reduction factors of micro-arcoxidation ceramic layers under different phase duty cycle modes

No.	Duty cycle/%	Thickness /μm	H_PRF
Ⅰ	40%-50%-60%	162.6	12.5
Ⅱ	50%-60%-40%	175.9	7.1
Ⅲ	60%-50%-40%	158.7	10.5

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