Preparation And Properties Of Ta-W Coating By Magnetron Sputtering On Gun Steel

With the development of the research on the protection of weapons and equipment,The development of artillery is limited by the fire intensity and the service life of the barrel.At present,increasing the firepower and extending the service life of the tube have become a hot topic for researchers.Therefore,more strict requirements are put forward for the ablative and abrasion resistance of the gun barrel.In this paper,the ta-w coating was coated on the steel surface by using multi-target magnetron sputtering and DC reactive sputtering.Simulated artillery firing conditions.The anti-ablative properties of the coating were tested by means of pulse heating of the sample by infrared laser.Friction and wear test was used to test the friction coefficient under high load and high speed.High temperature cyclic oxidation was used to test the oxidation performance of the samples at 900℃×30 times,and the wear,oxidation and ablative mechanism of the samples were studied by SEM,XRD and EDS.The thickness of ta-w coating prepared by magnetron sputtering was 42μm.The deposited ta-w coating is continuous,uniform and dense,with columnar crystal structure.The coating hasα-Ta andβ-Ta at the same time.The interpenetration of elements between the Ta-W coating and the steel helps to improve the bonding strength.In the laser ablation test,the area of ablation destruction will increase with the rise of laser energy.The ablation area of Ta-W coating was only 64%of that of steel substrate under the same irradiation energy.The Ta-W coating has advantages in ablative resistance.The hardness of Ta-W coating increased by 117%and the elastic modulus increased by 6%.The friction coefficient of Ta-W coating will increase with the growth of the loading force.In addition,the surface of steel substrate is more seriously worn than that of the coating.The wear mechanism of steel structure is fatigue wear,plastic deformation and extrusion deformation.The wear mechanism of ta-w coating is shear wear.The friction process promotes the oxidation of coating,and the oxide will reduce the friction resistance of coating.During the high temperature cyclic oxidation experiments,the oxidation kinetics curve of steel matrix approximately obeys the law of parabola,and the coating’s oxidation film flakes off quickly.The coating does not have a good oxidation resistance to the substrate.The oxidation products of ta-w coating are Ta₂O₅ and WO₃,while WO₃ is easy to sublimate above 850℃.Therefore W has fewer oxidation products.The main cause of coating failure is the oxidation reaction of O through ta-w coating and matrix.After tempering treatment,the retention time of the coating oxidation film on the substrate was prolonged,and the bonding force between the coating and the substrate was improved.