Preparation of high-density and excellent bending strength pure tungsten target by hot oscillatory pressing sintering and its magnetron sputtering coating.

The high-strength, high-density pure tungsten (W) targets were fabricated using hot oscillatory pressing (HOP) sintering. This study examined the influence of sintering temperature, oscillation frequency, amplitude, and median pressure on the relative density, grain size, and bending strength of the tungsten targets. A tungsten target exhibiting a relative density of 99.51%, a grain size of 2.95 μm, a bending strength of 1200.1 MPa, and a purity of 99.95% was synthesized at a sintering temperature of 1600 °C, an oscillation pressure of 60 ± 15 MPa, and a frequency of 1 Hz. Grain rearrangement and plastic deformation (dislocation movement and grain boundary slip) were identified as the primary mechanisms for grain refinement and densification, respectively. The key strengthening mechanism was sub-grain boundary strengthening. The optimal tungsten target was utilized for magnetron sputtering on a reduced activation ferritic/martensitic (RAFM) steel substrate. The effects of sputtering time, power, deposition pressure, and substrate temperature on the crystallinity, roughness, thickness, and bonding force of the tungsten films were investigated. The optimal magnetron sputtering process was achieved by sputtering for 45 min at a power of 60 W, a deposition pressure of 15 Pa, and a substrate temperature of 100 °C. This resulted in dense W films with excellent comprehensive properties, including a roughness of R a = 8.73 nm, R q = 3.34 nm, a thickness of 999.05 nm, and a bonding force of 2.57 N. • High-density and excellent bending strength pure tungsten (W) target can be prepared by hot oscillatory pressing sintering. • Sub-grain boundary strengthening is the primary strengthening mechanism for W target by hot oscillatory pressing sintering. • Suitable substrate temperature can promote the crystallization, density, and bonding force of W films. [ABSTRACT FROM AUTHOR]