Effect of Ni addition on the mechanical and degradation properties of hollow glass microsphere/Mg alloy composites

Highlights: • Adding Ni results in the formation of Al₃Ni₂ intermetallic compound. • Al₃Ni₂ phase is distributed in the β-phase and can act as micro-galvanic cathode. • High strength and rapid degradation rate are obtained. • The influence mechanism of Ni on degradation property is revealed. -- Abstract: Magnesium-based degradable alloys and composites have recently gained great attention as promising candidates for the degradable fracturing tools of the unconventional oil and gas development field. The aim of this study was to evaluate the effect of Ni content on the mechanical properties and degradation behavior of the HGM/Mg alloy degradable composites. The results showed that adding Ni led to the formation of Al₃Ni₂ intermetallic compound, refined the matrix alloy grain and improved the mechanical properties. The Al₃Ni₂ phase was distributed in the β-phase and thereby reducing the function of corrosion barrier of the β phase and promoting the corrosion products to peel off during the degradation process. Meanwhile, Al₃Ni₂ phase can act as micro-galvanic cathode to accelerate the micro-galvanic corrosion rate. Thus, the degradation rate of the composite was significantly increased. The highest degradation rate (95.6 mg cm⁻² h⁻¹) in 3.5 wt% KCl solution at 93 °C was obtained in the composite containing 2 wt% Ni, which is 3 times higher than that of the composite without Ni.