Preparation And Properties Of Ni/Al Layered Energetic Structural Materials By Composite Method

The Ni/Al layered energetic structural material is a new type of energetic structural material with high energy density,strength and insensitivity.It is highly valued by researchers because when its component is impacted on the target,the kinetic energy penetration and high reaction release energy characteristics can greatly improve the comprehensive damage effect.In this paper,Ni/Al multilayer energetic structural materials with interlayer thickness of micron-scale were prepared by a composite method,and their reaction properties and mechanical properties were studied.Firstly,the micron-sized nickel layer was prepared on the aluminum foil by electroless nickel plating.The effect of electroless nickel plating temperature and sodium hypophosphite concentration in the nickel plating solution on the surface quality of the electroless nickel plating layer were analyzed.The surface quality is better at 80?and sodium hypophosphite concentration of 15 g/L.Then Ni/Al layered energetic structural materials were prepared by hot press composite method in“Al-Ni-Al-Ni”stacking order.The effects of hot pressing temperature and time on its interface evolution,exothermic properties and tensile strength were investigated.It was found that the optimum hot pressing process was at 300?for 30 min.Under this process,the interface of Ni/Al layered composites was well bonded and had high reaction energy density and tensile strength.Secondly,the reaction properties of Ni/Al layered energetic structural materials were studied.The reaction property of Ni/Al layered energetic structural materials with original nickel-aluminum layer thickness ratios of 1/2,2/3 and 1/1 were tested by Differential Scanning Calorimetry?DSC?.It was found that with the increase of the thickness of the nickel layer,the reaction exothermic performance increased first and then decreased.Among them,the 2/3 Ni/Al layered energetic structural materials had the highest reaction energy density which was 1051.62J/g.XRD test results showed that AlNi,Al₃Ni and Al₃Ni₂ compounds were formed after the reaction.The activation energy E of the reaction exothermic peak was calculated by the Kissinger and the Ozawa method for the 2/3 Ni/Al layered energetic materials.The activation energies obtained by the two methods were similar,and the activation energy of the heat peak increased in sequence as the peak temperature increased.During the accumulative roll bonding process,the thermal exothermic performance increased with the increase of the load force on the material.When the 2/3 Ni/Al layered energetic structure materials was subjected to the rolling load force of 6.0×10⁵ N,the exothermic energy density of the instantaneous g reaction reached 1311.79J/g.The laser ignition test on 2/3 Ni/Al layered energetic structural materials was carried out with different laser energies.It was found that it could be successfully ignited with bright red-yellow sparks.As the laser energy increased,the spark gradually increased,and there was a throwing effect.Finally,the tensile,bending and interlaminar shear properties of Ni/Al layered energetic structural materials with different layer thickness ratio structures were investigated and their failure modes were analyzed.As the thickness of the nickel layer increased,the tensile strength and flexural strength increased,and the tensile and flexural strength of the 1/1 Ni/Al layered energetic material were337.64MPa and 345.60MPa respectively.The tensile failure mode was characterized by of delamilation mixed with fracture.The interlaminar shear strength decreased with the increase of the thickness of the nickel layer,and the interlayer shear strength of the 1/2 Ni/Al layered energetic material was the largest,which was 8.32MPa.