CS225120B2 - The production of substrates with coating - Google Patents

Abstract

1426384 Ethylene oxide SAES GETTERS SpA 30 April 1973 [29 April 1972] 20455/73 Heading C2 [Also in Divisions B1-B2] Ethylene oxide is prepared by reacting ethylene with oxygen in the presence of a catalyst prepared by mixing alumina (which passes through a screen of 100 mesh per inch and is retained on a screen of 600 mesh per inch) and silver (passes screen 400 mesh per inch) in a weight ratio of 3 : 7, placing the mixture on either side of an aluminium substrate 0À01 inches thick and having a Vickers hardness of 90 kg./mm.<SP>2</SP>, placing two intermediate bodies of iron having Vickers hardness of 180 kg./mm.<SP>2</SP> and thickness of 0À01 inches on either side of the particles, passing the resultant composite through rotating rolls and then removing the intermediate iron bodies leaving the hard particles embedded in the aluminium substrate and the soft particles adhered thereto.

Description

The invention relates to a process for the production of a substrate coated with particles having a high surface area to mass ratio. '

A process for the production of substrates on which hard metal particles are anchored is known, for example, from Bris. No. 1,139,135. However, it has hitherto been believed that such methods are only suitable if they are used. if the particles are harder than эдЬь ^ 1И. This considerably narrows the moonost of choice of hard-matte material, although the known processes have many advantages, such as a lack of binder, moonost to carry out such processes at room temperature and the possibility of reducing roll wear, as well as the possibility of forming structures with higher surface area ratios. matter.

Uve ^d en ^Star nedootatky removes ^{characterized} discovery ee ^h s ^{* i} ^ Disclosure is made of ^PU with ^b productions ^would su ^ t ^ herein having a coating of particles with high surface area to mass, wherein the present invention between здЬь ^ ¹ about tvrdossi according Vlckerse of ^d 9 ^d of -81 ³⁹²⁰ ИЯ / ш ² and BC-ly body of tvrdossi Vickers 98.07 ^d from about ⁵⁸⁸⁰ MN / m ² Filing ^{asks tшёs,} ICI-contained hard Wstice from MMAE Vickers ^{981 d} of ^{29 420} WVm ² and particle sizes ^{from 25} μm to ¹⁰ μm

2 ^{'1 s} 50/1 and soft particles of metal on tvrdossi ^p ccording Victors ^0.98 Ш ш ^ ¹ to 9 and ⁶⁰ in ^e likes of particles from 0.015 to 50 V / i, přieemž individual values are selected within these ranges so that the hardness of the stick body is always higher than the hardness of the hard body, the hardness of the hard core is higher than the hardness of the solid body and the softness of the soft parts is lower than the hardness of the hard core. The adhesive body and hard particles are compressed and the contact body with the smmsi particles is further compressed and the hard particles are pulled into the tubular body by the attachment body and the soft particles are forced to adhere to the adhesive by the attachment body. after which the accessory body is finally removed from the particle contact and the hard particles remain pressed into the particle and the soft particles remain adhered to the sulfate.

The contact body preferably has a Vickers hardness 492 MN / m ² lower than the hard particles. Preferably, the substrate has a Vickers hardness at least 392 MN / m less than the support body. The soft particle size according to a further feature of the invention is 1/2 to 1 / 10,000 hard particles.

The soft metal used is preferably a catalytic metal, for example silver.

Non-metal, for example alumina, is preferably used as the hard particle material with a Vickers hardness of 981 to 29 420 MN / m.

In contrast to the prior art, the method of the present invention allows the materials of the particles to be made into the substrate to be extended to materials of lesser hardness than the substrate, while maintaining the other advantages of the prior art.

The principle of anchoring soft particles on the surface of a harder substrate while achieving a high surface area, surface to mass ratio of the coating, i.e. porosity, can be explained as follows. If the aforementioned set of elements, ie the substrate, the attachment body and the intermediate layer of hard particles and soft particles, is compressed, for example, by passing through a pair of nip rollers, presses the attachment body onto particles of both types and partially pushes the hard particles into the substrate of both materials. However, since the hard particles are harder than the attachment body, they are temporarily slightly pushed into the surface of the attachment body. Due to their hardness, however, despite this partial pressing of the hard particles, the substrate and the attachment body separate from each other.

This means that the soft particles extruded into the space between the individual hard particles are only partially compressed. This partial compression results in the plastic deformation of the soft particles being cold welded and the particles adhering to each other, to the substrate, and possibly also to the hard particles and to the contact body. However, the presence of hard particles as spacers ensures that the sintered mass of soft particles remains porous.

With respect to the ratio of hardness to the greater compression of the hard particles into the substrate than to the attachment body, the coating thus formed remains adhered to the substrate and the separation of the attachment body overcomes the adhesion resulting from some compression of the hard particles into the attachment body as well as cold welded soft particles. Apparently this is also aided by the fact that the soft particles adhere to the substrate and the hard scrubber in a substantially larger area than to the contact body.

The effect of the invention is thus achieved in particular by using the hard particles simultaneously as an intermediary ensuring adhesion of the soft particle coating to the substrate when separating the attachment body and improving the adhesion of the soft particles to the substrate due to mechanical anchoring in the substrate surface. allowing the sintering of the soft particles without excessive compression to the non-precursor layer. This has hitherto prevented the anchoring of coatings of the particles softer than the substrate by a purely mechanical route: the use of binders, since limiting the pressure by the spacer layer of the hard particles has always compressed the soft particles to a non-porous mass.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of an apparatus for carrying out the process of the present invention; and FIG. 2 is a sectional view taken along line 2-2 of FIG. according to the invention.

In the drawings, and in particular in FIG. 1, a device 10 for carrying out the method according to the invention is shown. In this method, the mixture of soft and hard particles and 12 is deposited between the substrate 13 and the upper liner 14, and between the substrate 13 and the lower liner 15. The formed assembly is passed between two rollers 16, 17 which rotate in the direction of the arrows 18 and 24.

The device 40 is provided with means to maintain a smaller distance between the two rollers 16 than the combined thickness of the subwire assembly. In a preferred embodiment, where the contact bodies 14 and 15 are mehnically hardened, the rollers 16 and 17 press the contact bodies 14 and 15 with such a force that the contact bodies they deform plastically with simultaneous mechanical strengthening and, in addition, press the hard particles with a mixture of soft and hard particles 11 and 12 against the area 33 without substantially reducing the total area that the particles in the mixtures 11 and 72 have.

The entire assembly leaves the gap between the rollers 16 and 17 together with the supporting bodies 54 and 55. lying on the mixtures of particles 11 and 62. that adhered to the sub-substrate. Příoožná tělesa. 4a and 15 are then removed, leaving the resultant article 20 consisting of a substrate 13 and a coating. As a result of the hardness relationship described herein between the particles in directions 12 and 12, the substrates and the adjacent bodies 14 and 12, both hard and soft particles will bring to the sub-substrate £ 3. This relationship of hardness is of decisive importance for the successful execution of the method according to the invention. For example, when the accessory bodies 14 and 15 have the same hardness as the sub-substrate 83, the hard particles in the mixtures 11 and 12 would in the unforeseen multiplicity begin to enter the sub-substrate 13 as well as the accessory bodies 14 and 12, while If the sub-wire 13 is harder than the contact body 14 e 12, the hard claws would be anchored in particular to the access body 14 and 15.

Fig. 2 shows a sub-wire 13 having anchored large hard particles 11 and smaller soft particles 11 The composite structure shows that the structure is highly porous with the result that the total surface area of the soft particles 11 is practically reduced to their original surface area before This structure is chaaterial to the articles made by the process of the present invention using the use of ancillary bodies and the underside of the substrate 13 likewise comprises hard particles '12' and soft particles. In one embodiment of the invention, the hard particles 11 ' and 12 ' are constituted by alkaline acid and the soft particles 11 and 112 are formed with a slab.

The hard particles may have very variable bees, but are generally particles that pass through a 3.94 mesh / 10 mesh standard sieve, and are preferably those that pass through a 100 mesh screen. which are retained on the sieve 23 (5.22 mesh / cm (600 meehh). The soft particles must pass through a sieve of 19.69 mesh / cm (50 meehh), preferably pass through a sieve

3.94 mesh / cm (10 mesh) and ideally pass through a mesh of 7.88 mesh / cm (2Θ meeh). However, they are generally smaller than hard particles

In principle, a minimum size of soft particles is not determined. In fact! the smaller the particles, the larger their surface area. This is particularly advantageous when the resulting structure has a simple catalyst. However, the usual soft particle size is 1/2 to 1 / 10,000, and preferably 1/10 to 1 / 5,000, the size of the hard particles. During sissing of the assembly, this allows the hard particles to provide a distance between the accessory bodies and the substrate, so that the soft particles will not be compressed, which would result in an undesirable reduction in their surface area.

Both the wide and the preferred Vickers hardness limits for the contact body, particle and substrate are given in the following table:

čLožka Wide range of MNO ² The preferred range is MN / m ² contact body 98.07 to 5880 981 to 2940 hard particles 981 to 9 810 1 960 to 7 850 soft particles. 0.98 to 1,960 .9.81 to 981 9.81 to 3,920 98.07 to 1,960

If the above hardness ratios are maintained, the values given in the table are not limiting in the sense that they have to select specific values within the ranges indicated. In a preferred embodiment of the invention has the straight těleso'tvrdost Vickers least about 490 and preferably about them NEJM ^é '981 MN / m ² lower than the hardness tvi ^{d h} yc particles. Subbtoát has a ^"p hardness ccording Victarse NEJM Step ^E of ³⁹² and preferably tube bundle $ Step ^E of 785 MVM ni ^ i ² not ^from the straight toles. Soft particles are not hard: - than a sub-substrate and are usually softer than the sub-substrate. '

The soft particles may be particles of any metal or substance. In a preferred embodiment in which the resulting structures are catalytic structures, the soft particles are in the catalytic metals. The catalytic metal, however, is selected with regard to the chemical reaction involved, which is not the subject of the invention. Typical examples of suitable catalytic metals. are in particular silver, gold, platinum, mixtures thereof and alloys thereof between them and the other metals.

From the broadest aspects of the invention, the hard particles may be cellular or non-metallic, but non-metallic is preferred. When the resulting structure was to be used for catalysis, the hard particles did not interfere with the course of the chemical reaction. Examples of suitable metals include, but are not limited to, zirconium, vanadium, tantalum, and titanium. Examples of suitable non-metals are silicon carbide, silicon nitride, boron nitride, silica and alumina, which is particularly preferred. The most preferred subgroup of materials for non-metallic hard particles are refractory oxides.

The ratio of hard particles to soft particles can be varied within wide limits, provided that the advantageous effect of the invention is achieved. However, this ratio is usually between 1:20 to 1: 4 and preferably 1:10. and 1: 1. At substantially lower pommers, there is a lack of hard particles needed to provide the separation between the rigid body and the substrate. Doing so would cause undesirable flattening - or softening. . particles and thereby also reduce their total surface area. A further undesirable consequence of low relative ratios is the reduction of adhesion of the shallow particles to the sub-substrate. At higher relative proportions, the total surface area of the shallow particles is low simply because they are present - less monohydrate.

The cubate and the hollow bodies may be formed of any metal having the required hardness. Examples of suitable metals are, among others, soft iron, steel, aluminum and stainless steel. It should be pointed out that the chemical nature of the strand-forming elements to be applied to the sub-substrate is not critical. It will be appreciated that alloys may be used for both the substrate and the support body, provided they have different hardnesses. however, it must not have an inhibitory effect on the catalytic reaction.

It will be appreciated by those skilled in the art that different hardnesses can be achieved using conventional mallurgical techniques such as hot-milling, cold-rolling and the like.

The invention is further explained by the following examples, wherein parts and percentages are parts by weight and percentages unless otherwise indicated. Examples of the least omenjc! it is important for the scope of the invention and is only intended to explain it in greater detail.

Example 1

The example illustrates the method of the invention, wherein the resulting structure is a catalysis device.

Referring to Figure 1, a 3: 7 mixture of finely divided particles of light oxide and silver is prepared and deposited on each side of the hinnium oxide. of a 0.025 cm thick substrate. The aluminum oxide passes through a 100 mesh screen and is retained on a 600 mesh screen. The silver is passed through a 400 mesh sieve. Sutbtrát has a hardness ccording Vic ^p ^ ^ RSE 883 ms ^{1 second} To preach ^dé side fitted mixture "particle ^Annex one přHotaěm body that ^Z Iron has compounding hardness ^p ccording Victerse ^{1 * * * 770} Ж / m ² and a thickness ^ 0.025 cm, and the assembly is passed to ^ t slot MEEI two milliamperes rotating rollers. The contact bodies are then removed and the hard particles, i.e., alumina, remain anchored in the substrate and the soft particles, i.e., silver, adhere to the substrate.

Example 2

This example is intended to overcome the apparatus of the present invention for catalysis. The catalysis apparatus of Example 1 produced operates satisfactorily to increase the reaction rate of the reaction of ethylene with oxygen to form ethylene oxide.

Example 3

This example illustrates a method according to the invention, wherein the resulting structure is another catalysis device.

A mixture of finely divided silicon carbide particles (kerborunda) and copper in a 3: 7 weight ratio was deposited on each side of the low-thickness steel wire with a thickness of 0.025 cm. Silicon carbide pass through a screen mesh of 39.37 / cm (100 mesh) "and retained on a sieve of mesh counts of 15 ⁷ to 48 1 cm (400 meeh). MEA 15 ⁷ passes through 48 mesh / cm (400 meehh. Suubsrát has a Vickers hardness of 9 ^ ¹ x Ю ² MN / m ^2. KA ^moves Subbu ^^ ou side at ^{about a} train having p ^m avenging Annex ^P of one přHel em-body a hardness ^{axes d} and ^3.92 GlVm ² and a thickness of ^{0, 0} 25 'and the resultant cm ^and the assembly was passed through a nip between two rotating rollers. intermediate body is then removed and the hard particles, i.e. carbide The silicon remains anchored in the susceptible and soft particles, i.e. the copper, adhere to the sulfate.

he said a d 4

The resulting catalysis apparatus works successfully to increase the reaction rate of carbon monoxide with water vapor to generate hydrogen.

Claims (8)

Process for the production of particles with a coating of particles having a high surface area to mass ratio, characterized in that the Vickers hardness between 9,81 and 3 920 MN / m is between the tubstrate. 8 přHožrté body of hardness' by ^ C ^ rse from ^98.07 to ⁵⁸⁸⁰ Wm ² imposes mixture encompass tougher ^é mmateiftu amount of the t-vrtossi by ^{V ic} ERSE ^981-29 420 MN / m ² and ^ Tossi nuts from 25/1 to 150yu a'měkké particles of metal tvrdossi Vickers from 0.98 MN / m to ⁶⁰ 9 ^{1 MN /} m ² and velifossi MSI-IC from 0 ° ^{15/1 50/1 U} o ^p s ^e EMZ as ^d but ^{by carefully} hodnoS ^y VOH within the ranges such that the hardness at ^ nného body is' always higher than the hardness of the substrate, the hardness of the hard particles is higher than the hardness of the substrate induced by the body and the hardness of soft čássic lower than the hardness of the substrate, the cross-body and the hard particles, the substrate and the cross-body in the mixture particles are further compressed and the hard particles are pushed by the cross-body into the substrate and the soft particles are forced to adhere to the substrate by the cross-body. ze sty particles and the hard particles on the substrate remain pressed into the substrate and the soft particles remain adhered 2. The Vickers method of claim 490, wherein a shim body having a hardness MN / m ^{&lt; 2 &gt; is} lower than the hard particles. according to item 1j indicated 3. Method Vickeree is at least 392 MN / m ^ lower than by using a contact body. substrate ₃ having a hardness according to 4. The method is 1/2 to 1/10 according to item 1, characterized by 000 hard particles. by using soft particles whose size 5. A process metal according to claim 1 wherein the metal of the soft particles is a catalyst 6 · Method according to item 5, characterized in that silver is used as the catalytic metal 7. The method of Vickeree according to 981-29 420 point marked. 2 by 1, MN / m * is used non-metal as a hard particle material of hardness 8. The method of claim 7, wherein a metal such as alumina is used.