Belt-type Apparatus Research Articles

A distinctive HPHT platform with different types of large-volume press subsystems at SECUF

Large-volume presses (LVPs) providing large volumes, liquid media, deformation capability, jump compression, and in situ measurements are in great demand for high-pressure research, particularly in the fields of geoscience, condensed matter physics, material science, chemistry, and biology. A high-pressure and high-temperature (HPHT) platform with different LVP subsystems, both solid-state and liquid environments, and nonequilibrium subsystems, has been constructed at the Synergetic Extreme Condition User Facility, Jilin University. This article describes the construction of the different subsystems and provides an overview of the capabilities and characteristics of the different HPHT subsystems. A large sample volume (1000 mm3) at 20 GPa is achieved through the use of a belt-type apparatus in the solid-state subsystem. HPHT conditions (1.8 GPa and 1000 K) are realized in the liquid subsystem through the use of a piston–cylinder-type LVP with optical diamond windows for in situ spectroscopic measurements. A maximum pressure jump to 10.2 GPa can be reached within 20 ms in the nonequilibrium subsystem with the use of an improved bladder-pressurization jump press. Some typical results obtained with different LVPs are briefly reviewed to illustrate the applications and advantages of these presses. In summary, the platform described here has the potential to contribute greatly to high-pressure research and to innovations in high-pressure technology.

Decomposition behavior of GaN under solid and ambient N2 pressure

We investigated the decomposition behavior of GaN crystals under high N2 and solid pressures using a belt-type high-pressure apparatus. The decomposition curve of GaN under solid pressure showed a considerably moderate increase compared to that under a N2 pressure. Such difference was attributed to the N2 dissolution in the Ga melt, where a high N2 pressure creates a supersaturated GaN state, which effectively prevent its decomposition. Conversely, under a solid pressure, the increase in the GaN decomposition temperature followed a common change in enthalpy, which is consistent with its typical thermodynamic behavior. The decomposition behavior of GaN under a solid pressure demonstrated its successful high-temperature annealing using a belt-type high-pressure apparatus. Therefore, this study provides valuable insights into the thermodynamic stability of GaN under different pressures, which is critical for optimizing high-performance GaN-based devices.

High-Pressure Synthesis of Th3P4-Type c-Zr3N4 Using a Metathesis Reaction and In Situ X-ray Diffraction Studies of the Formation Process

We have successfully prepared highly crystalline Th3P4-type Zr3N4 (c-Zr3N4) using a high-pressure metathesis reaction utilizing a belt-type high-pressure apparatus and determined synthesis conditions. A combination of ZrCl4 and Ca3N2 was used as the Zr and N sources, respectively, which enabled the synthesis of c-Zr3N4 crystals, whereas another combination of Zr and N sources produced only NaCl-type ZrN (δ-ZrN). It was found that 6.5 GPa was the lowest synthesis pressure available for the synthesis of c-Zr3N4 at temperatures ranging from 1400 to 1500 °C. In situ X-ray diffraction was performed at 9.3 GPa, which revealed that the appearance of the intermediate phase during heating was key to the synthesis of c-Zr3N4, when the combination of ZrCl4 and Ca3N2 was used as the starting material.

Experimental results on the high-pressure phase diagram of boron nitride

We present the boron nitride (BN) phase diagram at 3–6 GPa and 1100 °C–2200 °C using a modified belt-type high-pressure apparatus. The cubic BN (cBN)–hexagonal BN (hBN) phase boundary was determined using the hBN–Mg3BN3 catalyst system as a starting material at 4–5.5 GPa. Additional experiments were conducted at 3–4 and 4–6 GPa using cBN powder or hBN–Ca3B2N4 catalyst as a starting material. In the hBN–catalyst system, the rate of cBN nucleation was reduced by the growth of metastable hBN crystals under the cBN-stable pressure–temperature conditions. The stable BN phases were identified from the samples reacted with a longer run duration. The phase boundary line between hBN and cBN was determined as the equation P (GPa) = T (°C)/400 + 0.3, which agreed with the boundary lines calculated by Gruber and Grüneis and by Nikaido et al.

Synthesis of cubic zirconium(IV) nitride, c-Zr3N4, in the 6–8 GPa pressure region

We report on the lowermost pressure and temperature conditions where cubic zirconium(IV) nitride having Th3P4-type structure, c-Zr3N4, forms in a belt-type apparatus. This novel hard material having exceptional wear resistance by machining of low-carbon steels appears at pressures between 6.5 and 7.7 GPa when heated to 1400–1600 °C. Single-phase samples were obtained at P = 7.7 GPa thus indicating that the industrial scale synthesis of this innovative material is feasible. Chemical reaction of the sample material with the Pt-capsule led to formation of a Pt–Zr alloy, as a minor admixture, which can potentially be used as a binder for cementing of polycrystalline c-Zr3N4 tools.

High pressure pulsed electric current activated equipment (HP-SPS) for material processing

An innovative new system under high pressure syntheses activated by pulsed electric current (HP-SPS) was designed and built in-house with belt type apparatus (HP-SPS-Belt). This new HP-SPS- Belt with large volume chamber is capable of reaching high pressures up to 6GPa and temperatures until 1800°C. This system was pressure and temperature calibrated by using different metal calibrants. To demonstrate the efficiency of this new equipment in the present work, we have successfully shown the structural γ to α phase transformation in alumina under less severe conditions than in conventional high pressure and temperature processes. Further, we have also used this new HP-SPS-Belt to fabricate shear cutter for drilling bits in an economical way of fabrication. This study shows the wide interest of our unique designed equipment for various applications in materials processing to better control their microstructure and their properties.

Numerical simulation and experiment on split tungsten carbide cylinder of high pressure apparatus.

A new high pressure device with a split cylinder was investigated on the basis of the belt-type apparatus. The belt-type die is subjected to excessive tangential tensile stress and the tungsten carbide cylinder is easily damaged in the running process. Taking into account the operating conditions and material properties of the tungsten carbide cylinder, it is divided into 6 blocks to eliminate the tangential tensile stress. We studied two forms of the split type: radial split and tangential split. Simulation results indicate that the split cylinder has more uniform stress distribution and smaller equivalent stress compared with the belt-type cylinder. The inner wall of the tangential split cylinder is in the situation that compressive stress is distributed in the axial, radial, and tangential directions. It is similar to the condition of hydrostatic pressure, and it is the best condition for tungsten carbide materials. The experimental results also verify that the tangential split die can bear the highest chamber pressure. Therefore, the tangential split structure can increase the pressure bearing capacity significantly.

Study on stress distribution of tangent split high pressure apparatus and its pressure bearing capacity

The ultra-high pressure device with tangent split tungsten carbide cylinder is investigated on the basis of the belt-type apparatus. The cylinder is divided into six blocks and the dividing line is tangent to the inscribed circle of the regular hexagon inner hole. Then the divided bodies assemble the high pressure cylinder. This structure of cylinder eliminates the tangential tensile stress and produces a great tangential compress stress through the friction and squeeze each other on the contact surface between the divided bodies. Simulation results show that the maximum shear stress and equivalent stress on the tangent split cylinder are much smaller than those on the belt-type cylinder. The principal stresses on the inner wall of the tangent split cylinder are all compressive stresses. And the situation that compressive stress is in three directions is akin to the condition of hydrostatic pressure, the best condition for tungsten carbide materials. The experiment results also prove that the tangent split die can bear higher oil pressure than the belt-type die.

Short review of high-pressure crystal growth and magnetic and electrical properties of solid-state osmium oxides

High-pressure crystal growth and synthesis of selected solid-state osmium oxides, many of which are perovskite-related types, are briefly reviewed, and their magnetic and electrical properties are introduced. Crystals of the osmium oxides, including NaOsO3, LiOsO3, and Na2OsO4, were successfully grown under high-pressure and high-temperature conditions at 6GPa in the presence of an appropriate amount of flux in a belt-type apparatus. The unexpected discovery of a magnetic metal–insulator transition in NaOsO3, a ferroelectric-like transition in LiOsO3, and high-temperature ferrimagnetism driven by a local structural distortion in Ca2FeOsO6 may represent unique features of the osmium oxides. The high-pressure and high-temperature synthesis and crystal growth has played a central role in the development of solid-state osmium oxides and the elucidation of their magnetic and electronic properties toward possible use in multifunctional devices.

A novel split-belt apparatus: the stress distribution and performance of its tangent split die

A novel high pressure device with a tangent split cylinder was investigated on the basis of the belt-type apparatus. The cylinder is split into several blocks and the dividing line is tangent to the inner hole. This structure of the cylinder can eliminate the tangential tensile stress due to the friction and squeeze each other on the contact surface between the divided bodies. In this paper, different split numbers of the cylinders were choosen to study the stress distribution and the pressure-bearing capacity, and compare them with the traditional belt-type die (BTD). Simulation results show that the more the number of divided bodies, the smaller the stress and the higher the pressure-bearing capacity. The experiments also indicate that the tangent split die can bear higher pressure than the BTD. The tangent split tungsten carbide cylinder has the advantages of easy manufacture, strong bearing capacity and replaceable performance.

Synthesis of ternary Si clathrates in the A–Al–Si (A = Na and K) system

With the aim of producing functional materials based on earth-abundant elements, we examined the synthesis of the ternary type-I clathrates A8AlxSi46−x (A = Na and K). The type-I Si clathrate K7.9(1)Al7.1(1)Si38.9(4), having a lattice parameter of 10.434(1) Å, was successfully synthesized via the direct reaction of K, Al, and Si by optimization of both the synthesis temperature and the molar ratios among the raw ingredients. K8Al7Si39 exhibited metallic conduction: its electrical resistivity increased with increasing temperature. The high pressure synthesis of Na8AlxSi46−x was also examined, using a belt-type apparatus and employing a mixture of NaSi, Al, and Si as the reagents. In this manner, the type-I Si clathrate Na8.7(9)Al0.5(1)Si45(2), having a lattice parameter of 10.211(1) Å, was synthesized at 5.5 GPa and 1570 K.

Homogeneous heating of a sample space by a modified heating assembly in a belt-type high-pressure apparatus.

To create homogeneous heating in the sample space in a belt-type high-pressure apparatus, modified heating assemblies under pressure of 2.5 GPa and temperature up to 1700 °C were examined. Counterbores (with several diameters) were made at both ends of a cylindrical graphite heater to suppress the temperature gradient along the cylindrical axis of the heater. Temperature distributions within the heaters were measured by thermocouples and geothermometers. Both sets of measurements revealed that the temperature distribution in the sample space (6.9 mm outside diameter/12 mm length) was homogenized (i.e., variation of less than 10 °C under heating at 1700 °C) by optimizing the heater shape.

Preparation and Properties of Ultra-High Temperature Ceramics Based on ZrC and HfC

Successful preparation of massive compact bodies from ultra-high temperature ceramics like zirconium carbide, hafnium carbide and their cermets with tungsten matrix with high values of mechanical parameters is difficult. Only limited number of techniques is able to perform it because of their absolutely highest melting points. In our contribution the preparation of these materials by both - hot pressing and plasma spraying techniques is described and chemical processes taking part at the fabrication are studied. Hot-pressed products fabricated at 2000°C and 6 GPa partly react with the internal surface of the BELT-type apparatus. Melting and solidification is taking place at plasma spraying. This process, carried out by water stabilized plasma torch with centerline temperature up to 30 000°C, is joined with undesirable reactions with plasma-forming medium, with oxidation in a turbulent plasma flow and nitridation of free-flight particles. All these chemical processes depend on variety of parameters, such as particle size of the feedstock powders or electric power of the arc. The mentioned parameters are easily controlled. Other, less controllable, factors include trajectory of powder particles in the plasma jet, important for the melting degree as well as for oxidation or nitridation of the powder surface. New knowledge concerning properties of compact ZrC and HfC were obtained.

Synthesis of high-crystallinity cubic-GaN nanoparticles using the Na flux method—A proposed new usage for a belt-type high-pressure apparatus

We developed a gas-sealing technique by adopting a metal capsule in a belt-type high-pressure apparatus, which enabled a supply of high-pressure nitrogen gas of several hundred MPa. With employing the sealing technique, cubic-GaN (c-GaN) nanoparticles were successfully synthesized using the Na flux method under nitrogen pressure above 100 MPa. A high cubic/hexagonal ratio of more than 20 can be achieved by optimizing the synthesis conditions. An attempt was made to functionalize c-GaN by doping Eu element as a luminous origin. Cathodoluminescence and XANES study revealed that Eu can be doped into the c-GaN particles, causing them to take on the state of Eu 3+.

ChemInform Abstract: A Redetermination of the Crystal Structure of Trimagnesium Platinum, Mg3Pt.

Abstract Single crystals of Mg3Pt have been obtained from the elements by high pressure-high temperature reaction in a modified Belt-type apparatus. The compound crystallizes hexagonally, space group P63cm, with a=7.9103(8) A , c=8.3223(16) A , c/a=1.0521 and Z=6. The structure refinement (R=0.027, Rw=0.022 for 264 absorption-corrected reflections) shows unequivocally that Mg3Pt is isostructural with Cu3P and that the structure models proposed by Ferro and Rambaldi (Na3As type, space group P63/mmc) and Mansmann (anti-LaF3 type, space group P 3 c1 ) are wrong.

Synthesis, stability range and characterization of Pr2Cu2O5

A novel Pr2Cu2O5 phase has been prepared under high-pressure and high-temperature conditions (P ∼6 GPa and T ∼1673 K) in a Belt-type apparatus and characterized by X-ray diffraction and electron microscopy. The crystal structure appears to be an orthorhombic “oxygen-deficient perovskite” (M.T. Anderson, J.T. Vaughey, and K.R. Poeppelmeier, Structural similarities among oxygen-deficient perovskites, Chem. Mater. 5 (1993), pp. 151–165) isostructural with La2Cu2O5 (J.F. Bringley, B.A. Scott, S.J. La Placa, R.F. Boheme, T.M. Shaw, M.W. McElfresh, S.S. Trail, and D.E. Cox, Synthesis of the defect perovskite series LaCuO 3−δ with copper valence varying from 2+to 3+, Nature 347 (1990), pp. 263–265) and Nd2Cu2O5 (B.-H. Chen, D. Walker, E. Suard, B.A. Scott, B. Mercey, M. Hervieu, and B. Raveau, High pressure synthesis of NdCuO3−δ perovskites (0≤δ≤0.5). Inorg. Chem. 34 (1995), pp. 2077–2083).

Growth of PrFeAsO1−y single crystals and its characterization

Single crystals of oxygen deficient oxypnictide superconductor PrFeAsO1−y have been grown by using belt-type anvil high-pressure synthesis apparatus. Superconducting transition temperature (Tc) of the obtained single crystal is 45K, and typical size is about 800×1000×30μm3. In-plane electrical resistivity shows s-shaped behavior, and can well be fitted by T1.2 temperature dependence near 150K. In addition, we obtained non-superconducting parent single crystal by annealing the as-grown single crystal under ambient pressure. Resistivity of parent single crystal is characterized by the kink near 150K corresponding to the structural transition, and the structure near 12K, which is thought to be originating from the magnetic order of Pr ion.

La content dependence of superconducting critical temperature in filled skutterudite LaxRh4P12

La content dependence of superconducting critical temperature (Tc) of LaxRh4P12 was investigated. The samples were synthesized using a belt-type high-pressure apparatus at pressures of 5.5 and 7.7 GPa, and temperatures of 1373 and 1473 K. The La content (x), the lattice parameter and Tc increase when the synthesis pressure is increased. These results suggest that both the lattice parameter and Tc increase with x, when x is in the range 0.70 to 0.85.

Superconducting properties of filled skutteruditeLa0.8Rh4P12

The superconducting properties of filled skutterudite ${\mathrm{La}}_{0.8}{\mathrm{Rh}}_{4}{\mathrm{P}}_{12}$ synthesized at $9.4\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ and $1473\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ using a belt-type apparatus were investigated by measuring the magnetization, electrical resistivity, and specific heat. Filled skutterudite ${\mathrm{La}}_{0.8}{\mathrm{Rh}}_{4}{\mathrm{P}}_{12}$ is a type-II superconducting material with a critical temperature for the superconducting transition, ${T}_{C}$, of $14.9\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The upper critical field ${H}_{C2}(0)$ and Ginzburg-Landau coherent length $\ensuremath{\xi}(0)$ were determined to be $167(1)\phantom{\rule{0.3em}{0ex}}\mathrm{kOe}$ and $4.41(1)\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, respectively. The electronic heat-capacity coefficient ${\ensuremath{\gamma}}_{n}$ and the Debye temperature ${\ensuremath{\Theta}}_{D}$ were $25.1(8)\phantom{\rule{0.3em}{0ex}}\mathrm{mJ}∕\mathrm{mol}\phantom{\rule{0.2em}{0ex}}{\mathrm{K}}^{2}$ and $459(12)\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, respectively. Using ${T}_{C}$ and ${\ensuremath{\Theta}}_{D}$, the electron-phonon coupling constant $\ensuremath{\lambda}$ was estimated to be approximately 0.7, suggesting that ${\mathrm{La}}_{0.8}{\mathrm{Rh}}_{4}{\mathrm{P}}_{12}$ is an intermediately coupled superconducting material.

A Novel Ferrimagnetic Irido‐Cuprate: IrSr2GdCu2O8.

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