DE102008047334B4 - Process for the preparation of hydridic room temperature superconductors on the surface of substrates - Google Patents

Abstract

Process for the production of "hydridic" room temperature superconductors from palladium, an alkali or alkaline earth metal and an isotope of hydrogen, characterized in that the alkali or alkaline earth metal is deposited reductively from an alkali or alkaline earth compound on a palladium substrate and the resulting palladium / Alkali alloy or palladium / alkaline earth alloy is then hydrogenated / deuterated with hydrogen and / or deuterium at 100–150 bar for 10–30 minutes.

Description

Almost all chemical elements exhibit superconducting properties under extreme conditions such as low temperature (near absolute zero) and / or high pressure (GPa).

Noteworthy is the fact that certain mixed oxides (cuprates), which should by convention be insulators, have this property already 100 K above absolute zero.

For unrestricted technical use, however, materials are needed which have superconducting properties at room temperature and normal pressure, if possible.

Superconductivity is characterized by the fact that electric current flows almost without resistance. In this case, the charge is not transported by individual electrons but by electron pairs, so-called Cooper pairs.

According to the classical theory, the resistance arises from collisions and scattering of the flowing electrons with lattice defects and atomic hulls.

The resistance increases with increasing temperature due to the parallel increasing lattice vibration.

According to this, the resistance could be eliminated if the collisions between electrons and atomic hulls at the atomic level are prevented.

• – Elektronen und Atomrumpf nicht voneinander getrennt vorliegen, sondern eine Einheit bilden
• – alle Elektron/Atomrumpf-Paare im Gitter im gleichen Takt in gleicher Ebene schwingen.

This succeeds when:

• - Electron and atomic nucleus are not separated, but form a unit
• - swing all electron / atomic core pairs in the lattice in the same cycle in the same plane.

On the other hand, the electrons between the pairs must be easily displaced.

An easy mobility of electrons is known from mesomerizable systems, such as the conjugated polyenes.

Conjugated polyenes

• + CC = C - C - ← → C = CC = C ← → - C - C = C - C +

According to Little ^1,2 ), conjugated polyenes with strongly polar side groups have the potential to form a superconductor with transition temperature> 273 K.

An analogous state can be obtained for mirror-image-isomeric coordination compounds Image ( 1 ) after doping with strongly polar compounds.

Of all elements, palladium has the highest storage capacity for hydrogen.

During loading, the hydrogen molecules on the surface of the palladium are split into hydrogen atoms and distributed to the lattice cavities in the palladium. Formally, an octahedral coordination compound of the type image ( 1 ). In this coordinate compound hydrogen and palladium have the same electronegativity (according to Pauli = 2.1).

If the Pd / H lattice is doped with hydride ions by incorporation of alkali metal or alkaline earth metal hydrides, the coordinating compound forms a mesomerizable CT unit, which can be abstracted from the coordination geometry as follows:

A conductive scaffold is formed by n-fold three-dimensional reoccurrence of these units in the Pd matrix.

The conductivity collapses when the kinetic energy of the lattice vibration is greater than the binding energy of the van der Waals forces formed hydrogen bonds between the hydrogen atoms.

Examples of the Production of Superconducting Surface Layers

• – Herstellung einer Pd/Me'-Legierung (Me' = Alkalimetall) bzw. Pd/Me''-Legierung (Me''=Erdalkalimetall) auf der Oberfläche eines Substrats.
• – Hydrierung der Pd/Me'- bzw. Pd/Me''-Legierung zu einem Pd/Me'/H- bzw. Pd/Me''/H-System.

Following the discussed model, the following steps are necessary for the synthesis of a hydridic superconductor:

• - Preparation of a Pd / Me 'alloy (Me' = alkali metal) or Pd / Me '' alloy (Me '' = alkaline earth metal) on the surface of a substrate.
• - Hydrogenation of the Pd / Me 'or Pd / Me''alloy to a Pd / Me' / H or Pd / Me '' / H system.

Production of a Pd / Me layer on the surface of a substrate

As a substrate, massive Pd substrates and substrates with only one surface layer of palladium in the micron range were used.

• – Reduktion eines Alkali-/Erdalkaliorganyls mit atomarem Wasserstoff
• – Elektrochemische Reduktion eines Alkali-/Erdalkalihydrids.

For deposition of the alkali / alkaline earth metals on the substrate surface, the following reduction methods were carried out:

• - Reduction of an alkali / Erdalkaliorganyls with atomic hydrogen
• - Electrochemical reduction of an alkali / alkaline earth hydride.

Reduction of alkali / alkaline earth compounds with hydrogen

The experiments were based on the idea of depositing alkali / alkaline earth metals from organic alkali / alkaline earth compounds with the aid of atomic hydrogen on the surface of palladium substrates. Helpful here is the fact that hydrogen dissolves in bulk in palladium.

For this purpose, in an autoclave ( 2 ) the palladium substrate surface of substrates ( 4 ) with hydrogen passing through the inlet valve ( 3 ) was fed, saturated at pressures between 10-150 bar. The saturation was determined by constant pressure on the manometer ( 5 ) read. Pd + H2 → Pd (H2)

After saturation, the autoclave was placed over the riser ( 8th ) relaxed. The hydrogen-saturated substrate was then passed through the valve ( 6 ) with butyllithium solution ( 7 ) of different molarity (2.5-10 m) at room temperature. Thereafter, via the inlet valve ( 3 ) hydrogen again pressed.

The following reaction sequence was expected: Pd (H2) + ButLi → PdLi + ButH

A deposition of the lithium metal on the palladium surface could only be achieved with 10 m butyllithium solution and H 2 pressures <10 bar.

At higher pressures> 10 bar, the following competition reaction proceeded preferentially: ButLi + H2 - ButH + LiH

Due to the extreme risk of fire when handling 10 m butyllithium, it was desirable to achieve this with 2.5 molar solution.

Deposition of lithium from low-molar butyllithium solutions was possible despite pretreatment (activation) of the palladium layer z. B. are not enforced by heating to 800 ° C in a stream of hydrogen.

For the subsequent hydrogenation of the surface-produced palladium / lithium alloy, the excess butyllithium was introduced via the riser integrated into the autoclave ( 8th ) sucked off.

The procedure described requires complete freedom from oxygen and moisture in the entire autoclave system. For this purpose, the autoclave had to be heated to 200 ° C and slowly cooled with a dry stream of hydrogen to room temperature.

Lowest traces of moisture z. B. in the shut-off valve ( 6 ) or the riser ( 8th ) lead to contact with the Butyllithiumlösung immediately unrecoverable jamming of the valve.

Because of the described technical difficulty, it was obvious to take alternative ways to produce the palladium / alkali or palladium / alkaline earth metal alloy.

Electrolytic deposition of alkali / alkaline earth metals

Due to the position in the voltage series, the electrolytic deposition of alkali / alkaline earth metals is possible only in aprotic solvents.

The problem here is the poor solubility of electrolyzable compounds in such solvents.

Furthermore, only compounds which are not covered by industrial property rights for similar uses should be used as the compound.

Alkaline or alkaline earth metal hydrides in tetrahydrofuran (THF) were used as the electrolyte.

For this purpose, predried THF ( 9 ) in an electrolysis vessel ( 10 ) submitted. Via the gas inlet tube ( 11 ) was bubbled through the THF for 0.5 h (O2 flash). The bubbled hydrogen was passed through the gas discharge tube ( 12 ) derived.

Via a dosing device ( 13 ) Lithium hydride (LiH) was added in excess (gray-turbid solution). The excess ensures that no moisture remains in the electrolyte.

The electrode-palladium anode ( 14 ) and the palladium cathode = substrates ( 15 ) were connected to a 12 volt power source ( 16 ). Throughout the electrolysis time (0.5-2 h), a moderate flow of hydrogen was bubbled through the electrolyte.

The current flow is extremely low with 5-20 μA.

The deposition of lithium on the substrate surface (gray coating) is nevertheless reproducible.

An analogous procedure was successfully carried out with calcium hydride.

Hydrogenation of the Pd / Li or Pd / Ca alloy to the Pd / Li / H or Pd / Ca / H system

The Pd / Li or Pd / Ca coated substrate was transferred to an autoclave after electrolysis. At pressures of 100-150 bar hydrogen saturation of the substrate was achieved between 10-30 minutes (constant pressure).

Resistance measurement on Pd / Li / H or Pd / Ca / H systems

The resistance of the substrates was measured indirectly by the four-point method as a voltage drop.

Under the same measuring conditions (T = 20 ° C, I = 43 mA), the following values were measured: on the Pd substrate 0.8 mV on the Pd / Li substrate 1.2 mV on the Pd / Li / H substrate 0,000 mV

After a few seconds in the air, the value of the Pd / Li / H system changes from 0.000 mV to 1.2 mV.

LIST OF REFERENCE NUMBERS

1

Mirror image isomeric coordination complex

2

high-pressure autoclave

3

intake valve

4

palladium substrate

5

manometer

6

Inlet valve for liquids

7

butyllithium

8th

riser

9

electrolyte

18

electrolysis vessel

11

Gas inlet tube

12

Gas discharge tube

13

metering

14

Pd anode

15

Pd-cathode

16

voltage source

Claims (9)

Process for the preparation of "hydridic" room temperature superconductors from palladium, an alkali metal or alkaline earth metal and an hydrogen isotope, characterized in that the alkali or alkaline earth metal is deposited from an alkali or alkaline earth metal compound reductively on a palladium substrate and the resulting palladium / Alkali alloy or palladium / alkaline earth alloy is then hydrogenated / deuterated with hydrogen and / or deuterium at 100-150 bar 10-30 minutes. Process for the preparation of "hydridic" room temperature superconductor according to claim 1, characterized in that as palladium substrate massive palladium is used as wire or foil. Process for the preparation of "hydridic" room temperature superconductor according to claim 1, characterized in that are used as the palladium substrate body of any material whose surface is coated with palladium> 10 microns are used A process for the preparation of "hydridic" room temperature superconductor according to claim 1, characterized in that the deposition of the alkali metal or alkaline earth metal from the alkali / alkaline earth metal compounds by atomic hydrogen on the palladium substrate. Process for the preparation of "hydridic" room temperature superconductor according to claim 1, characterized in that the deposition of the alkali metal or alkaline earth metal from the alkali / alkaline earth compound is carried out by current on the palladium substrate. A method for producing "hydridic" room temperature superconductor according to claim 4, characterized in that the deposition of the alkali or alkaline earth metal on the palladium substrate, by means of hydrogen stored in the substrate from an alkyl lithium or Alkylcalciumverbindung, but preferably from a Butyllithium or Butylcalciumverbindung. Process for preparing "hydridic" room temperature superconductor according to claim 5, characterized in that the deposition of the alkali metal or alkaline earth metal by electricity from electrolytes such as lithium hydride in tetrahydrofuran or calcium hydride in tetrahydrofuran on the palladium substrate connected as a cathode. Process for the preparation of "hydridic" room temperature superconductor according to claim 1, characterized in that is used as hydrogen isotope, hydrogen or deuterium at higher pressures, preferably up to 150 bar. Process for the preparation of "hydridic" room temperature superconductor according to claim 1, characterized in that are used as hydrogen isotope mixtures of hydrogen / deuterium in any ratio at higher pressures, preferably up to 150 bar.

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