*2.2. Mechanical Properties*

The densities of the composites were determined using Archimedes's principle. Microhardness was measured on a Micro-hardness Tester (MH-5-VM, Shanghai Hengyi Technology Co., Ltd., Shanghai, China). with a load of 500 g and a dwell time of 10 s. Flexural strength and compression strength were measured using a universal material tester (SANS-CMT5205, Shenzhen New Sansi Material Testing Co., Ltd., Shenzhen, China). The three-point bending test was conducted to obtain the flexural strength, and the samples were cut to 3 mm high × 4 mm wide × 20 mm long. The cross-head speed and span were 0.05 mm/min and 16 mm, respectively. The sizes of the samples for the compression strength test were Φ 5 mm × 12.5 mm, and the cross-head speed was 0.2 mm/min.
