Fig. 1. Schematics of (a) KLVP and (b) first-stage mold. The black dashed lines surround the various components of the press, as well as the first-stage anvil.

Fig. 2. Cross sections of high-pressure assemblies with two configurations. (a) Conventional pressure-calibrated assembly. (b) 8/3 conventional HPHT assembly. (c) 8/3 new assembly with ultrahard materials (d) 8/3 new HPHT assembly. 1, Cu foil (or cylinder); 2, sample; 3, 5 wt. % Cr₂O₃-doped MgO pressure medium with 8 mm edge length; 4, zirconia thermal insulator; 5, hexagonal boron nitride; 6, Re heater; 7, dense magnesia; 8, dense alumina disk; 9, dense alumina sleeve; 10, boron-doped diamond; 11, thermocouple; 12, mullite tub.

Fig. 3. (a) and (b) Resistance variations of ZnTe and GaP, respectively, upon compression in an 8/3 conventional assembly. (c) Pressure generation in conventional cell assemblies with ZK01F and ZK10F WC anvils. (d) Heating behaviors of Re heaters for the 8/3, 10/4, and 14/8 assemblies.

Fig. 4. (a) and (b) Resistance variations of GaP and Fe₂O₃, respectively, upon compression in the present new 8/3 cell assembly. (c) High-temperature generation in the present new 8/3 cell assembly at 50 GPa.

Fig. 5. Representative Raman spectrum (a) and backscattered electron image (b) of the run product recovered from 50 GPa to 1900 K. Brg, bridgmanite; Cor, corundum.

Fig. 6. (a) Comparison of pressure generation of the ZK10F WC anvil with the present new 8/3 assembly (NA) and ZK10F, ZK01F, and TJS01 anvils with a conventional 8/3 assembly (CA). (b) Comparison of ultrahigh pressures generated by WC anvils above 50 GPa in KLVPs in the present and previous studies. The previous studies are as follows: ZK01F + 6/1.5, Ref. 18; Tap.ZK01F + 6/1.5, Ref. 17; TF05/TJS01 + Trim. Oct./3, Ref. 15; TF05 + 7/3, Ref. 39; TF05/Tap.TF05 + 5.7/1.5, Ref. 20; TJS01 + 4/1 and Tap.TJS01 + 5.7/1.5, Ref. 19. When comparing with the Osugi-type KLVPs, the press load of conventional KLVPs is multiplied by 3.

Fig. 7. Capacities for pressure generation at high temperatures in KLVPs with WC anvils, as reported in the present and previous studies: HA-6% Co, Ref. 40; F, F08, S01, Ref. 41; ZK01F, Ref. 21; Tap.ZK01F, Refs. 17 and 18; Tap.TJS01, Ref. 19; Tap.TF05, Ref. 20.