JPS58107437A - Alloy based on palladium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to metallurgy, and in particular to alloys of noble metals, and more particularly to alloys based on palladium tubes.

Palladium-based alloys are used as membranes for the purification of hydrogen by diffusion, as catalysts for processes involving hydrogen transfer in the chemical industry, and as electrodes, thermocouples, electrical contacts, in medicine, electrical engineering and instrument manufacturing. potentiometric materials,
Ushidatsuki is used as a composition village.

To obtain ultrapure hydrogen through isolation of hydrogen-containing mixtures or purification by commercial hydrogen diffusion, hydrogen permeable membranes made from alloys based on radium and palladium have been used. the current.

Alloys containing up to 4#0 chains are used (West German Patent No. 1.JOJ, !f!; U.S. Patent No. 3゜Co07.Act; Ni. Journal of Physical Research of Rosina Township v-1/f7f, No. J, @ 1Jz011.”)).

The maximum hydrogen permeability is unique to alloys containing 7.4 to 1% silver by weight. Also used are silver/l-:LS-containing alloys. In order to obtain a higher stability of the latter alloy, other elements 1 such as indium can be incorporated (
(See Nee Nee Yoshina et al.'s Journal of @Physical Association Gate Story, 10 years ago, No. 1, page 1111).

However, silver-containing alloys are not very active in chemical processes involving hydrogenation and dehydrogenation.

Other palladium-based alloys containing gold, steel, boron, nibkel, rhodium, cerium, yttrium and platinum used in hydrogen purification either have insufficient mechanical strength (e.g. (added alloys), will be destroyed under the influence of hydrogen and other aggressive media (
Neezy Knapton's "Platinum Metals Levi 1-J, / Deaf 7 years, Volume 1), see page 0)
When gold, steel, and silver are blended with palladium, the catalytic activity of -5 radium in the dehydrogenation reaction decreases. Incorporation of platinum makes palladium more durable and increases catalytic activity, but significantly reduces the hydrogen permeability value of the alloy. and β are formed and - if present - reduce the selectivity of catalysts made from radium alloys and are the reason for their destruction under the influence of hydrogen. !, No. 700 discloses a membrane for hydrogen purification made from a palladium alloy containing !% by weight of ruthenium, although the hydrogen permeability of this alloy exceeds that of pure palladium.

This alloy has a short lifetime when operated in hydrogen and hydrocarbon atmospheres with multiple cycles of heating and cooling, and has two hydride phases (α and β).
have low selectivity when carrying out contact methods that may involve the presence of During use of the membrane, an α#β transition occurs, resulting in destruction of the membrane. Moreover, the presence of two hydride phases substantially reduces the selectivity of the catalytic method of hydrogenation and dehydrogenation, since the reactions occurring at the active centers of these phases have different mechanisms and kinetics. The purpose is not to be destroyed in a hydrogen atmosphere.

Furthermore, palladium-based alloys are proposed that can increase the selectivity of the contact method.

This purpose contains ruthenium and rare earth elements, and has the following composition Ruthenium Reference - 1 Weight - Rare earth elements
0. J-1 Weight - Palladium
This is achieved by an alloy based on palladium with the remainder.

Alloys of the above composition are very stable during operation, and ruthenium! It withstands heating-cooling cycles three times more than conventional alloys containing silica.

As mentioned above, the alloy of the present invention contains ~1% by weight of rhdenium.
The range of ruthenium content in the alloy is limited by the hydrogen permeability and durability of the constant 41 alloy.

The minimum content of ruthenium (Reference 96) and the maximum content (1%
) The hydrogen permeability of the alloy with ruthenium does not differ substantially from the hydrogen permeability of the alloy with the optimum composition of ruthenium (Buy Emouglyatsunov $ DAN8B8B, /S73, Vol. J//, (See No. J, Part 1 J) If the ruthenium content is higher than rt4, the hydrogen permeability of the alloy 1 is substantially reduced. Alloys containing 4 more than 10% ruthenium are already binary alloys and cannot be processed.

Palladium alloys containing less atsxb and ruthenium have sufficient hydrogen permeability but insufficient durability when operating in hydrogen atmospheres.

The lower limit for the content of rare earth elements (RWE) is determined by the presence of a hydride phase.If the OREE content is less than O,S wt., an undesirable second hydride β phase is present in an amount of If the OREE content is greater than t-, most alloys are binary and cannot be processed.

Therefore, if the contents of ruthenium and REE are not within the above range, the desired results will not be obtained.

Various modifications are possible to the palladium alloy of the present invention.

In the case of alloys containing rank/and yttrium, the following compositions are recommended as Kl is also efficient due to high hydrogen permeability, heat resistance and selectivity in the contact method. 2/Evening 10.
3 - Weight - Palladium Balance Ruthenium - Weight - Yttrium 0.3-1% by weight Palladium
The palladium alloy with balance ruthenium and RIE is melted under a pressure of 400-100 m lag in an atmosphere of purified helium on a water-cooled steel hearth in an electric arc vacuum furnace with non-consumable tungsten electrodes.

The preliminary vacuum in the furnace chamber is JX/(7sa*Hg or more).

Alloying rare earth elements are placed within the alloy by intermediate ligatures (ligatures).
introduced through atur.). The composition of the alloy is controlled by chemical analysis.

All molten alloys have a fine-grained structure and are within solid solution.

A 100μ thick membrane-foil is produced from the alloy by a cold deformation process with intermediate vacuum annealing.

When measuring hydrogen permeability, the foil made in this way is fixed along the perimeter inside the reactor cell.

Hydrogen is introduced into the reactor cell from one side. The amount of hydrogen that passes through the foil is measured with a black thorn rod.

During operation, the foil is subjected to cyclic heating at temperatures in the range of 3°C to 00°C.

The accompanying drawing is a graph showing hydrogen permeability versus temperature for several palladium alloys. That is.

The well-known alloy of palladium and ruthenium (i%) (Track 1
1/), and alloys with added lanthanum.

The arrows in the alloys of palladium, ruthenium 49G, lanthanum o, 3ts (curve ko), palladium-ruthenium A%-lanthanum 0.6%C curve 3), and palladium-ruthenium 41s-raypyis<curve tsu)oram indicate temperature changes. indicates the direction.

From the graph, a very small hysteresis is observed in the track 114 within the investigated temperature range, and in one direction 11
It can be seen that it does not exist in the case of J and song@san. Alloy of palladium-ruthenium t%-lanthanum o, 6qA and 15 radium-ruthenium buty lanthanum l
There is no hysteresis in the hydrogen permeability curve for the - alloy.

Upon use of these alloys in an atmosphere of hydrogen or hydrogen-containing media, only the hydride α phase of 0 1111I is present in the alloys, indicating that there is no α#β transition etc. in these alloys. Similar hydrogen permeability and the absence of hysteresis in the curve showing the relationship between hydrogen permeability and temperature , % in the case of a 12 radium-ruthenium alloy with additions of ytrium, cerium, neodymium and samarium.

When carrying out the catalytic reaction (hydrogenation of pe/tadiene and nitrobenzene), the starting material is fed into the reactor through one side of the foil membrane under a vapor pressure of 10 Kg, and the hydrogen is fed into the reactor from the other side under a pressure of 1 atm. The feed rate of the starting compound vapor is 75-7 minutes. Example 1 Preparation of alloys of palladium, ruthenium and lanthanum. Their composition and strength properties are shown in Table I below.

Table I It can be seen from Table 1 that the addition of rank/ increases the mechanical strength of known alloys.

The high selectivity of the catalytic method for membranes from rank/doped alloys is shown in the hydrogenation reaction of pe/tagene. The process parameters are shown in the table below.

In the hydrogenation reaction of pentadiene/tan at a temperature of 120 °C, films of palladium alloy with ruthenium withstood tSO thermal cycles of heating and cooling, and palladium alloy with 0.3% of ruthenium and ruthenium/tan. membranes withstand jOO cycles, while membranes made from palladium alloys with ruthenium tIs and lanthanum O6 and -5 radium alloys with ruthenium tIs and lanthanum l- survive the entire operating period (100 cycles).
Cannot be destroyed for.

Example An alloy of copalladium, ruthenium and yttrium is prepared. Their composition and strength properties are shown in Table J [ below.

/″″− Table 3 The addition of yttrium can increase the mechanical strength of known alloys ◎ The improvement in the selectivity of the contact method for membranes from yttrium-doped alloys is due to the nitrope/zene Hydrogenation 1) Shown in O. Process characteristics are shown in Table 4Lk below.

Palladium in a reaction at a temperature of 0°C.

Alloys containing ruthenium 1- and buttrium J- can withstand three times more cycles than alloys consisting of palladium and ruthenium ts. The addition of yttrium improves the mechanical strength, heat resistance, and selectivity of conventional alloys. increase

Example 3 A palladium-ruthenium-cerium alloy, a palladium-ruthenium-neodymium alloy and a palladium-samarium alloy are prepared in the same manner. Their composition and mechanical strength properties are shown in Table j below.

Basic! The addition of cerium, neodymium and samarium increases the mechanical strength of palladium and increases the heat resistance as well as yttrium and prolongs the lifetime of membranes made from these alloys, as well as K Improving the selectivity of contact methods carried out using these alloys@

[Brief explanation of drawings]

The drawing is a graph showing the relationship between hydrogen permeability and temperature of palladium alloys. Trokhimova 15 Kave 201 0 Inventor Evgeny Mikhailovich Savitsky Soviet Union Moscow Ulitsa De Ulyanova 3 Powers Be 13 0 Inventor Alexander Piotrovich Savitsky
Mischenko Soviet Union Moscow Tevry Stan 2 Microlion 27 Kabe 427 0 Inventor Vladimir Mikhailovich Guriazunov Soviet Union Moscow Lomonosovsky Prospekt 14 Force Be-504 0 Inventor Maria Evgrafouna Sar 142

Claims (1)

[Scope of Claim] An alloy based on palladium blended with ruthenium, containing a rare earth element and having the following composition by weight: ruthenium ~r rare earth element
0.3~t palladium
An alloy based on palladium, characterized in that it has a remainder.