SE199233C1

SE199233C1 -

Info

Publication number: SE199233C1
Authority: SE
Publication date: 1965-01-01

Description

Uppfinnare: F Jeitner Prioritet begard friM den 11 november 1954 (Forbundsrepubliken Tyskland) Foreliggande uppfinning avser ett fOrfaringssalt for framstallning av sintrade, av pulveriserade metallkarbider, metallsilicider, metallborider eller liknande grundsubstanser (»hardmetallsubstanser») bestaende formkroppar, som innehalla A1203 Amin bindemedel och som kunna formas i en strangpress och efter foregaende torkning av presskroppen pa kant satt solidifieras genom sintring. The present invention relates to a process salt for the preparation of sintered, carbide metal or similar basic substances ("cemented carbide substances") containing sintered moldings and containing binders and can be formed in an extruder and after previous drying of the compact on the edge set solidified by sintering.

Dot är kant att till pulverisierade utgangsmaterial, som Oro utvalda alltefter formkroppens anvandningsandamal och besta av metaller, metallegeringar, metalloxider, metallsilicider, metallkarbider och dylika grundsubstanser eller blandningar av dessa material, tillsatta ett bindemedel, for att en formbar massa skall erhallas, som kan utformas i en strang- eller sankpress. Den pa detta satt erhallna presskroppen torkas, varefter den insattes i en sintringsugn. It is advisable to add to powdered starting materials, such as Oro selected according to the application and composition of the body and consisting of metals, metal alloys, metal oxides, metal silicides, metal carbides and similar basic substances or mixtures of these materials, a binder to obtain a moldable mass which can be formed in a string or sink press. The compression body thus obtained is dried, after which it is placed in a sintering oven.

De icke plastiska hardmaterialen, t. ex. kiselkarbid, aluminiumoxid, molybdensilicid, erfordra en hog bindemed6lkomponent, for att den med bindemedlet blandade massan skall erhalla den nedvandiga plasticiteten for den vidare bearbetningen. Sasom bindemedel anvandas harvid vanligen hogviskiisa kolloidala amnen av organiskt ursprung, enar kolloiden omgiver de enskilda pulverpartiklarna och astadkommer tillracklig glidformaga. Lampligen anvandas for detta andamal viii vatande losningar av vegetabiliska, strakt svallbara kolloider, sasom starkelse, agar-agar, eller andra organiska amnen, sasom oljor, palmitin- och stearinsyra. Aven konstplaster och dessas losningar anvandas sasom plasticitets- och bindemedel. Ndrvaron av sadana organiska plasti- Dupl. kl. 80 b: 8/11 citetsmedel Or emellertid joke onskvard, om man vill binda t. ex. metallpulver. Man dr da vanligen tvungen att utfora branningen i reducerande atmosfar under vate. Harvid farbrannes emellertid den organiska komponenten icke utan forkoksas och efterldmnar icke Onskvarda rester av kol. .Yid framstallningen av formkroppar, som efter sintringen icke skola uppvisa nagra forkoksningsaterstoder, anvander man ddrfor rena oorganiska bindemedel. The non-plastic hard materials, e.g. silicon carbide, alumina, molybdenum silicide, require a high binder component in order for the pulp mixed with the binder to obtain the lower plasticity for further processing. As binders are usually used in the case of highly viscous colloidal substances of organic origin, the colloid unites around the individual powder particles and provides a sufficient sliding shape. For this purpose, aqueous solutions of vegetable, highly swellable colloids, such as starch, agar-agar, or other organic substances, such as oils, palmitic and stearic acids, are used for this purpose. Artificial plastics and their solutions are also used as plastics and binders. The presence of such organic plastics- Dupl. at 80 b: 8/11 citation means Or, however, joke onskvard, if you want to bind e.g. metal powder. You then usually have to perform the firing in a reducing atmosphere under water. In this case, however, the organic component is not combusted but is coked and does not leave any residual carbon. In the production of shaped bodies which, after sintering, do not show any coking residues, pure inorganic binders are used for this purpose.

Det Or t. ex. kant att yid framstallningen av slapkroppar tillsatta finfordelad A120, sasom bindemedel i form av sinterlerjord till det sasom slapkorn tjanande hardmaterialpulvret och med vatten hoprora den till ett slam, som darefter Mlles i en form och torkas. Den p0 detta salt erhallna kroppen brannes sedan vid lerjordens sintringstemperatur. Detta forfaringssatt bar den nackdelen, att den massa, som skall bearbetas, är tunnflytande och icke later sig utformas i en strangpress, endr vid ringa vattentillsats icke den for strangpressen tillrackliga plasticiteten hos massan kan uppnas. It Or e.g. edge to yid the production of slap bodies added finely divided Al 2 O 2, as a binder in the form of sinter clay soil to the as slap grain serving hard material powder and with water mix it into a sludge, which is then Mlles in a mold and dried. The body obtained on this salt is then burned at the sintering temperature of the clay soil. This method had the disadvantage that the pulp to be processed is thin-liquid and cannot be formed in an extruder, even with a small addition of water the plasticity of the pulp sufficient for the extruder cannot be achieved.

For att plasticiteten hos lerjordsblandningar skall fOrbattras, ar det vidare kant att frata aluminiumoxidens yta med syror. En sadan behandling kan utforas saval med saltsyra som med aluminiumklorider och eventuellt med andra syror. Genom bildandet av en latt sOnderdelbar hydroxidklorid peptiseras aluminiumoxidkornets yta, varigenom friktionen mellan de enskilda partiklama starkt minskas. Den uppnadda plasticiteten f Or formningen av massan i en strangpress Or emellertid endast tillracklig, om de anvanda grundsubstanserna, vilka verka sasom magrings- 2— — medel, aro plastiska och deras andel i massan är liten i forhallande till bindemedlen. Den erforderliga plasticiteten for strangpressning av massor, som innehalla metallpulver eller hardmaterial, sásom metallsilicid och metallkarbid, kan emellertid icke uppna.s genom peptisering av den sasom bindemedel verkande A1203. Ofta dr en tillsats av saltsyra i sadana massor icke onskvard, om reaktioner med fyllmedlet kunna intrada. Dessutom angriper syran pressverktygen. In order for the plasticity of clay soil mixtures to be improved, it is further possible to remove the surface of the alumina with acids. Such a treatment can be carried out with hydrochloric acid as with aluminum chlorides and possibly with other acids. By the formation of a readily decomposable hydroxide chloride, the surface of the alumina grain is peptized, whereby the friction between the individual particles is greatly reduced. The plasticity obtained in the formation of the pulp in an extruder is, however, only sufficient if the basic substances used, which act as skinning agents, are plastic and their proportion in the pulp is small in relation to the binders. However, the required plasticity for extrusion of pulps containing metal powders or hard materials, such as metal silicide and metal carbide, cannot be achieved by peptizing the Al 2 O 3 acting as a binder. Often an addition of hydrochloric acid in such masses does not adversely affect reactions with the filler. In addition, the acid attacks the press tools.

Genom uppfinningen undvikes fratningen av aluminiumodden med syror och anvandningen av organiska plasticeringsmedel och mojliggores bildandet av en till och med for strangpressforfafarandet lamplig massa med hog halt av magringsmedel och 41803 sasom bindemedel. Genom forfaringssattet enligt uppfinningen kunna plastiska, i en strangpress utform.bara massor framstallas, som upp till 90 %, hanfort till massans totala volym, innehalla pulveriserade med svarighet pressbara grundsubstanser, vilka verka sasom magringsmedel och besta av metaller, metalloid-der, metallkarbider, metallsilicider, metallborider och liknande amnen eller blandningar av dessa amen. Denna h6ga halt av med svarighet pressbara magringsmedel kan till och med ytterligare Ras, om pressningen sker i sanke. Aven for framstallningen av konstkolkroppar är detta forfarande anvandbart, om sasom grundsubstanser anvandes pulveriserad koks, grafit eller dylikt. The invention avoids the abrasion of the aluminum cap with acids and the use of organic plasticizers and enables the formation of a pulp which is highly suitable for the extrusion process with a high content of lean agents and binders. By means of the process method according to the invention, plastic masses which can be formed in an extruder can be produced which, up to 90%, depending on the total volume of the pulp, contain powdered and responsibly pressurable basic substances which act as slimming agents and consist of metals, metalloids, metal carbides. metal silicides, metal borides and similar substances or mixtures thereof. This high content of responsibly compressible lean means can even further Ras, if the pressing takes place in sanke. This process is also useful for the production of artificial carbon bodies, if powdered coke, graphite or the like are used as basic substances.

En annan fordel med uppfinningen bestar dart att nagra tillsatser av flussmedel icke erfordras, sa att reaktioner av blandningskomponenterna undvikas och aluminiumoxidens temperaturhallfasthet icke forsamras. Dessa fordelar vinnas enligt uppfinningen darigenom, att till de pulveriserade grundsubstanserna sasom bindemedel tillsattes en blandning av fint pulveriserad, hogvoluminos A1203 (dvs. A1203 i sina olika modifikationer, med undantag av alfa-modikfiationen) och en losning av kolloidal, vattenloslig lerjord (lerjordsgel), vilken blandning blandas med de pulveriserade grundsubstanserna, tills massan erhailer for bearbetning i en strangpress erforderlig plasticitet och formbestandighet. Alfa-modifikationen skiljer sig som bekant frail ovriga modifikatoner av A1203 genom sin stone volym. Att denna modifikation skall anvandas uttryckes aven indirekt genom begreppet »hogvoluminos*. Den anvanda vattenlosliga, kolloidala lerjorden erhalles i handeln sasom kristalliniskt pulver under benamningen derjordsgel» och anvandes exempelvis inom textilindustrien for impregnering av vavnader. Another advantage of the invention is that no additives of flux are required, so that reactions of the mixture components are avoided and the temperature half-strength of the alumina is not compromised. These advantages are gained according to the invention in that a mixture of finely powdered, high-volume Al 2 O 3 (ie Al 2 O 3 in its various modifications, with the exception of the alpha-modification) and a solution of colloidal, water-soluble clay gel (clay earth gel) was added to the pulverized basic substances as binder. , which mixture is mixed with the pulverized basic substances, until the mass is obtained for processing in an extruder required plasticity and dimensional stability. As is well known, the alpha modification differs from other modifications of A1203 by its stone volume. That this modification is to be used is also expressed indirectly by the term 'hogvoluminos *. The water-soluble, colloidal clay soil used is commercially available as a crystalline powder under the name "earth gel" and is used, for example, in the textile industry for the impregnation of fabrics.

Losningen av den kolloidala vattenlogliga lerjorden kan anvandas i olika koncentration, varvid med stigande koncentration av losningen proportionellt stone mangder erfordras relativt den fasta A1203, for att den optimala plasticiteten skall uppnas. En sarskilt hog plasticitet ha blandningar, som ph en del A1203 innehalla ungefar 1 till 1,3 delar av en 30- till 50-procentig losning av den kolloidala lerjorden. Genom forandring av blandningsforhallandet och av koncentrationen av den kolloidala lerjordsliisningen kan det plastiska forhallandet av den av grundsubstanserna och den sasom bindemedel och plasticeringsmedel tjanande blandningen bestaende massan av kolloidal lerjordslosning med fint fOrdelad aluminiumoxid godtyckligt installas. The solution of the colloidal waterlogged clay soil can be used in different concentrations, whereby with increasing concentration of the solution proportional stone amounts are required relative to the solid Al 2 O 3, in order to achieve the optimum plasticity. Particularly high plasticity have mixtures, which ph part A1203 contain about 1 to 1.3 parts of a 30- to 50% solution of the colloidal clay soil. By changing the mixing ratio and the concentration of the colloidal clay soil solution, the plastic ratio of the mass of colloidal clay soil solution with finely divided alumina consisting of the base substances and the binder and plasticizer can be arbitrarily installed.

Massan beredes lampligast sa, att man invager grundsubstanserna och bindemedlets fasta komponenter i onskat forhallande och vdl blandar dem. Darefter tillsattes losningen ay den kolloidala lerjorden och blandas massan val i en trigeller valsknhdare, tills efter kort tid om c:a 10 till 20 minuter den gynnsammaste plasticiteten uppnatts och massan kan pressas. Presskropparna kunna godtyckligt efterbehandlas, enar de ha god formbestandighet fore och efter sin torkning. The mass is prepared most conveniently so that the basic substances and the solid components of the binder are weighed in the desired ratio and the mixture is mixed. The solution was then added to the colloidal clay soil and the pulp was mixed in a trigel roll mixer, until after a short time of about 10 to 20 minutes the most favorable plasticity was reached and the pulp could be pressed. The compacts can be arbitrarily finished, provided they have good dimensional stability before and after drying.

Vid de i praktiken genomforda forsoksserierna hade den till anvandning kommande grovkorniga lerjordsgelen en vattenhalt av 19 % (bestamd vid 105° C). Den invagdes i otorkat tillstand och losningar med destillerat vatten framstalldes i olika koncentration. Harvid erhollos for losningen vid stigande koncentration foljande specifika vikter och viskositeter: konc. % lerjordsgel spec. vikt (cP) 1,023 1,159 1,047 1,443 1,071 1,624 1,091,870 1,119 2,2 1,143 2,6 1,190 4,0 1,238 6,90 I det foljande anfbras nagra utforingsexempel ph massor, som aro framsrallda enligt uppfinningen och val kunna utformas sarskilt i en strangpress. 1) Vid bearbetning till sinterkorunddelar ha foljandeblandningsforhallandenvisatsig vara lampliga 1 del A1203 till 0,9 t % lerjordsgellOsning 1 * * 1,0 t % 1 »» * 1,1 t % 1 * * 1,2 t % 1 * * 1,3 t % 2) a 6 t SiC kornighet 0,06 mm 3 t A1203 4 t 40 % lerjordsgellosning Den torkade formkroppen innehaller56,5 % SiC 43,5 % A1203 b 2 t SiC kornighet <10 iz 3 t A1,03 4,5 t 35 % lerjordsgellosning Den torkade formkroppen innehaller31 % SiC 69 % A1,03 3) 9 t antracitpulver 3 t A1,03 4 t 50 % lerjordsgellosning — —3 Den torkade formkroppen innehdller64 % antracit 36 % A120, 4) 20 t finmalen molybdendisilicid 2 t A1203 t 50 % lerjordsgellosning Den torkade formkroppen innehaller 5) 3 t Ni-pulver 3 t A1203 3 t 40 % lerjordsgellosning Den torkade formkroppen innehaller58,3 % nickel 41,7 % A1203 De enligt de angivna blandningarna framstallda massorna giva efter utformningen i en strartgpress i fuktigt tillstand elastiska strangar, som aro formbestandiga fore och efter torkningen. Den hoga binde- och adhesionskraften hos blandningen av finfordelad A1202 och den vattenhaltiga losningen av sadana lerjordsgeler underlattar aven formbarheten enligt andra formningsmetoder, t. ex. vid sankpressning eller vid stampning eller skakning. Exempelvis tillsatser om fa procent av ett sadant bindemedel aro tillrackliga, for att en tillracklig bindehallfasthet i otorkat tillstand skall erhallas. Sadana kroppar kunna utan vidare handhavas i otorkat tillstand. Den filmliknande fordelningen av bindemedlet tillforsakrar aven vid sma bindemedelsmangder en hog hallfasthet i bract tillstand. Det är aven tankbart att anvanda forfaringssattet f Or framstallning av katalysatorer, vid vilka A1203 tjanar sasom katalysatorbarare. In the experimental series carried out in practice, the coarse-grained clay gel used for use had a water content of 19% (determined at 105 ° C). It was weighed in the undried state and solutions with distilled water were prepared in various concentrations. Harvid recovered for the solution at increasing concentration following specific weights and viscosities: conc. % clay soil spec. weight (cP) 1,023 1,159 1,047 1,443 1,071 1,624 1,091,870 1,119 2,2 1,143 2,6 1,190 4,0 1,238 6,90 In the following, some embodiments ph masses are presented which are according to the invention and choices can be designed separately in an extruder. 1) When machining into sintered corundum parts, the following mixing ratios must be appropriate 1 part A1203 to 0.9 t% clay gel solution 1 * * 1.0 t% 1 »» * 1.1 t% 1 * * 1.2 t% 1 * * 1, 3 t% 2) a 6 t SiC grain density 0.06 mm 3 t A1203 4 t 40% clay soil gel solution The dried mold body contains 56.5% SiC 43.5% A1203 b 2 t SiC grain size <10 iz 3 t A1.03 4, 5 t 35% clay gel solution The dried mold body contains 31% SiC 69% A1.03 3) 9 t anthracite powder 3 t A1.03 4 t 50% clay gel solution - —3 The dried mold body contains 64% anthracite 36% A120, 4) 20 t finely ground molybdenum molybdenum 2 t A1203 t 50% clay gel solution The dried mold body contains 5) 3 t Ni powder 3 t A1203 3 t 40% clay gel solution The dried mold body contains 58.3% nickel 41.7% A1203 The masses produced according to the specified mixtures a stragg press in a moist state elastic strands, which are dimensionally stable before and after drying. The high bonding and adhesion strength of the mixture of finely divided Al 2 O 2 and the aqueous solution of such clay earth gels also facilitate the moldability according to other molding methods, e.g. by compaction or by stomping or shaking. For example, additives of a few percent of such a binder are sufficient for a sufficient bond strength in the undried state to be obtained. Such bodies can easily be handled in an undried state. The film-like distribution of the adhesive also ensures a high half-strength in the bract state with small amounts of adhesive. It is also conceivable to use the process for the preparation of catalysts in which Al2 O3 serves as catalyst catalyst.

Claims

Pat ent ansprak:

A process for the preparation of sintered bodies of powdered metal carbides, metal silicides, metal borides or similar basic substances (the hard metal substance) containing Al 2 O (ie Al 2 O 3 in its various modifications, with the exception of the alpha modification) and a solution of colloidal, water-soluble clay soil (clay soil gel), which mixture is mixed with the pulverized basic substances, until the mass is obtained for processing in a blank press required plasticity and dimensional stability.

2. A process according to claim 1, characterized in that the water-soluble, colloidal clay soil, which as crystalline powder contains about 37 to 45% Al 2 O 3, was used in the solution in a concentration of 5 to 50% and in increasing concentration of the clay soil solution was added in larger amounts in relation to the quantity fixed, hogvoluminos A120 s.

A method according to claims 1 and 2, characterized in that the molded body dried after molding is subjected to annealing at a temperature at which sintering of Al 2 O 3 occurs.

4. A process for the production of shaped bodies, which mainly consists of sintered corundum, characterized in that fire aluminum or sintered corundum powder is used as the basic substance, which is mixed with the mixture consisting of finely divided, high-volume Al 2 O 3 and the solution of colloidal clay soil and the mixture dried and then sintered. Cited publications: Patentskrifter tram Sverige 21135; France 827 501; Germany 699 233; USA 1,107,012; 1,752,867; 1 760 360.