At last, the samples were annealed in a furnace under a program-controlled heating condition (from room temperature to 550 ◦C at a rate of 10 ◦C/min, and keeping at 550 ◦C for 1 h) in air surroundings.
At last, the samples were annealed in a furnace under a program-controlled heating condition (from roomtemperature to 550 ◦C at a rate of 10 ◦C/min, and keeping at 550 ◦Cfor 1 h) in air surroundings.