Electro-explosive Spray Deposition Method For The Preparation Of Magnesium Alloy Biomaterials

Electro-explosive jet deposition is a method of using high density current generated by pulse discharge of energy storage capacitor to heat the deposited material by ohmic heating,so that it can melt,vaporize and expan d,and finally explode.Explosive products are sprayed on the surface of the substrate with shock waves to form a deposition layer.Electro-explosion spray deposition has the advantages of low oxidation degree,small substrate heating and easy control of energy.It is suitable for spray forming of various small parts and is a deposition technology with great application value.Magnesium alloy has the advantages of high specific strength and specific stiffness,close density and elastic modulus to natural bo ne,good biocompatibility and biodegradability,and can be degraded automatically in organisms.Therefore,it is widely used in the field of biological materials,such as magnesium alloy bone plate and magnesium alloy vascular stent.In this paper,according to the characteristics of biomedical implant materials and the characteristics of magnesium alloy automatic degradation,the key technologies of preparing magnesium alloy biomaterials are proposed.An electro-explosion spray deposition device was design ed.The device is mainly composed of high-voltage charging and discharging system,wire feeding mechanism,electrode,automatic displacement device,circuit control system and wire pressing mechanism.The wire is sent to both ends of the electrode through the wire feeding mechanism,and the high-voltage generator is started to make the gas discharge between the wire and the electrode explode,and the deposition layer is formed on the surface of the substrate with the jet deposition of the electro-explosion shock wave.AZ92A magnesium alloy wires with diameter of0.3mm,0.4mm,0.5mm and0.6mm were selected as the electrodeposition materials.Under the conditions of charging voltage of12 k V,13 k V and14 k V,substrate deposition distance of25 mm,30mm and35 mm,the parts were prepared by electroexplosion spray deposition.The surface and section of the parts were characterized by scanning electron microscopy and energy dispersive spectrometer.The microhardness of the deposition layer was measured,and the process parameters of preparing magnesium alloy parts were optimized.The preliminary results of the preparation of magnesium alloy parts by electro-explosive spray deposition method are as follows : the wire diameter is 0.5 mm,the deposition distance of the substrate is 25 mm,and the charging voltage is 13 k V.The length,width and thickness of the magnesium alloy sheet obtained are 31.3 mm,11.8 mm and 0.2 mm,respectively.and the sedimentary layer has good continuity,compactness and uniformity;When the wire diameter is 0.5mm,the initial voltage is 14 k V and the substrate deposition distance is 25 mm,the inner diameter of magnesium alloy micro-tube is 3.6mm and the wall thickness is 0.2mm,which meets the size requirements of magnesium alloy micro-tube.