SE187373C1

SE187373C1 -

Info

Publication number: SE187373C1
Authority: SE
Publication date: 1963-01-01

Description

Uppfinnare: R C Folweiler Prioritet begard frdn den 28 flint 1961 (USA) FOreliggande uppfinning avser framstallfling av sammanhangande keramiska kroppar utghende fran separata delar av keramiska kroppar. Inventor: R C Folweiler Priority Required from 28 Flint 1961 (USA) The present invention relates to the fabrication of cohesive ceramic bodies from separate parts of ceramic bodies.

Sammanfogandet av keramiska delkroppar till hallfasta sammanhangande kroppar liar sedan lange utgjort ett problem Mom den elektroniska industrin och andra industrigrenar. Foremftl av denna typ, sasom elektronror och lampkolvar maste Horses med forslutningar, vilka aro kraftiga, bestandiga mot bildning av spanningssprickor pa grand av temperaturvariationer samt i manga fall vakuumtata. Hit-tills har man i dylika fall astadkommit fogar och tillslutningar med hj alp av minst en metalldel, som at forenad med en keramisk del. Dessa fogar och tillslutningar uppvisa begransad Virmaga att motsta kraftiga temperaturvariationer. Dessa brister bero atminstone delvis pit skillnaden i frftga om utvidgningskoefficient mellan de keramiska delarna och metalldelarna. liven om man lyckats anpassa utvidgningskoefficienterna for delarna till varandra mom ett begransat temperaturintervall, ha problemen att astadkomma tillfredsstallande sammanbindning av i kemiskt avseende olikartade material varit avsevarda. The merging of ceramic sub-bodies into semi-solid interconnected bodies has long been a problem for the electronics industry and other industries. Horses of this type, such as electron tubes and lamp bulbs, must have horses with closures which are strong, resistant to the formation of voltage cracks due to temperature variations and in many cases vacuum-tight. Hitherto, in such cases, joints and closures have been provided with the aid of at least one metal part, as if combined with a ceramic part. These joints and closures show limited Virmaga to withstand strong temperature variations. These shortcomings are due at least in part to the difference in coefficient of expansion between the ceramic parts and the metal parts. life if one has succeeded in adapting the coefficients of expansion of the parts to each other with a limited temperature range, the problems of achieving satisfactory bonding of chemically different materials have been considerable.

Problemen att framstalla tillfredsstallande sammanhangande eller enhetliga kroppar utgitende frail separata keramiska delkroppar ha varit sarskilt besvarliga i fraga om keramiska delar bestaende av aluminiumoxid, magnesiumoxid och/eller berylliumoxid. For att erhalla en kraftig forbindning eller tatning, som ar relativt okanslig for temperaturvaxlingar Mom ett mer eller mindre begransat intervall, har man i Adana fall hittills varit tvingad att tillampa mindre vanliga tatningsforfaranden, sasom anvandning av avfasad Wining (graded seal) eller en eller fler pit sarskilt satt forma-de metalliska tatningsdelar. The problems of producing satisfactory cohesive or uniform bodies emitting frail separate ceramic sub-bodies have been particularly problematic in the case of ceramic parts consisting of alumina, magnesium oxide and / or beryllium oxide. In order to obtain a strong connection or seal, which is relatively insignificant for temperature fluctuations with a more or less limited interval, in Adana cases it has hitherto been forced to apply less common sealing procedures, such as the use of bevelled Wining (graded seal) or one or more pit specially set shaped metallic sealing parts.

Dupl. kl. 21 g: 14/11 Det har nu visat sig, att man i enlighet med foreliggande uppfinning kan undvika dessa olagenheter yid anvandning av keramiska delar bestftende av ett eller flera av materialen aluminiumoxid, magnesiumoxid och berylliumoxid pa ett 8verraskande enkelt satt, sit att man erhaller ett enhetligt foremal, vilket uppvisar en sammanhangande och, om sit Onskas, lake poros eller vakuumtat fog mellan de enskilda delar, av vilka det sammansatta foremalet besta.r. Dupl. at 21 g: 14/11 It has now been found that in accordance with the present invention these imperfections can be avoided by using ceramic parts consisting of one or more of the materials alumina, magnesium oxide and beryllium oxide in a surprisingly simple manner, provided that one obtains a uniform form, which exhibits a coherent and, if its desired, lake poros or vacuum-tight joint between the individual parts, of which the composite form consists.

Foreliggande uppfinning avser ett forfarande for framstallning av sammanhangande keramiska kroppar av aluminiumoxid, magnesiumoxid och/eller berylliumoxid, vid vilket man sammanfbr tva eller flera pit lampligt satt formade delar av en eller flera av de namnda oxiderna, sit att gransytorna hos de intill varandra anordnade delarna bilda en tattslutande fogyta, varvid ett sammanhangande skikt av pulver med i huvudsak samma sammansattning som de sammanforda kropparna anbringats mellan de intill varandra anslutande ytorna hos varje par av samverkande fogytor, varefter man utsatter de sammanforda delarna fOr tryck, sit att pulvret sammanpressas, och braimer de sammanforda delarna medan de befinna sig under tryck under sit hang tid och vid sit hog temperatur, att en sammanhangande fog bildas mellan varje par ay delar, varvid denna branning, om sit onskas, kan fortsfittas tills fogarna aro vakuumtata. The present invention relates to a process for the production of continuous ceramic bodies of alumina, magnesium oxide and / or beryllium oxide, in which two or more pit-shaped parts of one or more of the said oxides are joined together, so that the spruce surfaces of the adjacent parts forming a tight-fitting joint surface, wherein a continuous layer of powder having substantially the same composition as the joined bodies is applied between the adjacent surfaces of each pair of cooperating joint surfaces, after which the joined parts are subjected to pressure, the powder being compressed, and braimered. they join the parts while they are under pressure during their hanging time and at their high temperature, that a continuous joint is formed between each pair of parts, whereby this burning, if desired, can be continued until the joints are vacuum-tight.

Vid genomforande av fOrfarandet enligt foreliggande uppfinning framstaller man tva eller fler ph lampligt salt formade keramiska delar av aluminiumoxid, magnesiumoxid och/ eller berylliumoxid, vilka var och en aro fOrsedda med fogytor, vilka mojliggora sammansattning av de enskilda delarna till en onskad sammansatt kropp. Dessa delar sammansattas ph sadant satt, att de samverkande fog- 2— — ytorna ph intill varandra anordnade delar bilda en tattslutande fog, i vilken ett sammanhangande skikt av ett keramiskt pulver med i huvudsak samma sammansattning som de keramiska delarna mellan varje par av sammanverkande fogytor. De sammanforda delarna utsattas darefter for tryck, sa att pulverskiktet sammanpressas, och utsattas darefter for inverkan av varme, medan trycket bibeMlles under sa lang tid och vid sa hog temperatur, att en atminstone sammanhfingande forbindning utbildas mellan varje par av enskilda delar. Det är uppenbart, att detta sammanbindande material har samma sammans5.ttning som de ursprungliga enskilda kernmiska delarna, sa att den erhallna sammanhangande keramiska kroppen i sin helhet uppvisar i huvudsak enhetliga utvidgningsegenskaper. In carrying out the process of the present invention, two or more pharmaceutically salt-formed ceramic parts of alumina, magnesium oxide and / or beryllium oxide are prepared, each of which is provided with joint surfaces, which enable assembly of the individual parts into a desired composite body. These parts are composed in such a way that the cooperating joints ph 2 - arranged parts next to each other form a tight-fitting joint, in which a continuous layer of a ceramic powder with substantially the same composition as the ceramic parts between each pair of cooperating joint surfaces . The joined parts are then subjected to pressure, so that the powder layer is compressed, and then subjected to the action of heat, while the pressure is maintained for such a long time and at such a high temperature that an at least cohesive connection is formed between each pair of individual parts. It is obvious that this bonding material has the same composition as the original individual nuclear parts, so that the resulting cohesive ceramic body as a whole exhibits substantially uniform expansion properties.

Sasom angivits i det foreghende kan branningen av de sammanfOrda delarna genomforas endast under sit rang tid oeh vid sit hog temperatur, att en sammanhangande forbindfling mellan de olika paren av enskilda delar utbildas. Det har visat sig, att detta minimiresultat kan erhallas, om branningen genomfores under minst 10 minuters tid vid en ternperatur av minst 1600° C. As stated above, the firing of the joined parts can be carried out only during its range time and at its high temperature, that a coherent connection between the different pairs of individual parts is formed. It has been found that this minimum result can be obtained if the firing is carried out for at least 10 minutes at a temperature of at least 1600 ° C.

Om sit onskas, kan emellertid branningen av de sammanforda delarna fortsfittas under sit hang tid och vid sit hog temperatur, att icke endast en sammanhangande forbindning mellan de enskilda delarna utbildas, utan aven denna fOrbindning Ores icke porOs eller vakuumtat. Detta resultat kan erhallas, om man genomfor branningen under minst 100 minuters tid vid en temperatur av minst 1700° C. If desired, however, the combustion of the interconnected parts can be continued during its hanging time and at its high temperature, so that not only a coherent connection between the individual parts is formed, but also this connection is not porous or vacuumed. This result can be obtained if the firing is carried out for at least 100 minutes at a temperature of at least 1700 ° C.

Det har visat sig lampligt att genomfOra denna branningsoperation i en atmosfar, som icke itr reaktiv i fOrhallande till de sammanforda delarna. F8r detta andamal har vatgas med en daggpunkt lagre an —40° C visat sig sarskilt lamplig. It has been found expedient to carry out this burning operation in an atmosphere which is not reactive in relation to the interconnected parts. For this purpose, hydrogen gas with a dew point lower than -40 ° C has proved particularly suitable.

Det har i praktiken i allmanhet visat sig lampligt att genomfora branningsbehandlingen i tva eller flera fran varandra skilda steg, om man onskar framstalla en sammanhangande enhetlig kropp med en sammanhangande vakuumtat forbindning eller tillslutning mellan varje par av de ursprungliga, enskilda, keramiska delarna. Vid det fOrsta av dessa branningssteg smaltes det sarnmanhangande pulverskiktet, som har anbringats mellan varje par av samverkande fogytor, sit att paren av enskilda delar sammanbindas till en sammanhangande delkropp. Detta branningssteg genomfores under minst 10 minuters tid vid en temperatur av minst 1600° C och ger upphov till bildning av en sammanhangande forbindning Indian varje par av enskilda delar. Det andra av dessa behandlingssteg genomfores vid en hogre temperatur under en avsevart lfingre tidrynad, och tjfinar till att omvandla de tidigare bildade sammanhangan de forbindningarna till en vakuumtat eller icke poriis tillslutning. For denim ytterligare branningsbehandling utsattes den forbranda kroppen for inverkan av en temperatur av minst 1700° C under minst 100 minuters tid, under vilka betingelser de sammanhangande fogarna bliva vakuumtata. Det har visat sig, att detta andra branningssteg lampligen genomfores vid en temperatur av 1800-1900° C under en tidrymd av 100-1000 minuter. In practice, it has generally been found convenient to carry out the burning treatment in two or more distinct steps, if one wishes to produce a coherent uniform body with a coherent vacuum-tight connection or closure between each pair of the original, individual, ceramic parts. In the first of these firing steps, the cohesive powder layer, which has been applied between each pair of cooperating joint surfaces, is melted so that the pairs of individual parts are bonded together into a continuous subbody. This firing step is carried out for at least 10 minutes at a temperature of at least 1600 ° C and gives rise to the formation of a cohesive compound Indian each pair of individual parts. The second of these treatment steps is carried out at a higher temperature for a considerable finger time, and tends to convert the previously formed connections to a vacuum-tight or non-porous seal. For denim further burning treatment, the burnt body is subjected to the action of a temperature of at least 1700 ° C for at least 100 minutes, under which conditions the continuous joints are evacuated. It has been found that this second firing step is suitably carried out at a temperature of 1800-1900 ° C for a period of 100-1000 minutes.

Av vasentlig betydelse for utbildningen av en sammanhangande fog fir, att de obehandlade sammanforda delarna utsattas fen. tryck och bibehallas under tryck atminstone under det fOrsta branningssteget. Aven om den i det fOrsta steget branda kroppen kan utsattas for tryck aven under behandlingen vid det andra branningssteget, ar detta icke erforderligt och naedfor vanligen icke heller flagon sarskild far-del. Of vital importance for the formation of a coherent joint is that the untreated interconnected parts be exposed fin. pressure and maintained under pressure at least during the first firing step. Although the body burning in the first stage may be subjected to pressure even during the treatment of the second stage of burning, this is not necessary and usually does not necessarily require a special benefit.

Sasom angivits I det foregaende an det vanligen lfimpligt att genornfora branningen i en atmosfar, som icke fir reaktiv i fOrhallande till de sammanforda delarna. Vid anvandning av den i det foregaende beskrivna i tva behandlingssteg uppdelade loranningen, an det emellertid icke erforderligt att anya nda icke reaktiv atmosfar under det fOrsta branningssteget, varfor anyandningen av en dylik atmosfar vanligen begransas till det andra branningssteget, vilket, sasom angivits i det foregaende, an avsedd att gOra de sammanhangande fogarna vakuumtata. As stated above, it is usually convenient to return the combustion to an atmosphere which is not reactive in relation to the interconnected parts. However, when using the lorannation described above in two treatment steps, it is not necessary to have any non-reactive atmosphere during the first firing step, so that the respiration of such an atmosphere is usually limited to the second firing step, which, as stated in the foregoing , is intended to vacuum the cohesive joints.

Det kontinuerliga skikt av keramiskt pulver, som an anbringat mellan de samverkande mot varandra avpassade fogytorna, skall yam. sit tunt som mojligt, for att kryrnpningen i radiell led skall bliva sit liten som mojligt efter branningen av de sammanfOrda delarna for utbildning av den i det fOrsta steget erhallna forbindningen. Det har visat sig, att den slutliga tjockleken hos den branda belfiggningen skall yam mindre an 0,254 ram, och att det ursprungliga pulverskiktet, fOr att man skall uppna denna slutliga tjocklek i brunt till-stand, skall ha en tjocklek av hOgst 2,54 mm, fOretradesvis 1,27-2,54 mm. The continuous layer of ceramic powder, which is applied between the cooperating joint surfaces, shall yam. as thin as possible, so that the shrinkage in the radial direction will be as small as possible after the burning of the joined parts for the formation of the joint obtained in the first step. It has been found that the final thickness of the fire bellows is less than 0.254 mm, and that the original powder layer, in order to achieve this final thickness in the brown state, should have a thickness of not more than 2.54 mm. , preferably 1.27-2.54 mm.

Enligt en sarskild utforingsform av foreliggande uppfinning kan man med latthet astadkomma en sammanbindning av tillslutningsplattor till de oppna andarna av ett r5rstycke, varvid dessa delar ha frarnstallts i fOrvag av pulverformig aluminiumoxid. (eller berylliumoxid och/eller magnesiumoxid) till lamplig form. Sasom forfaranden for formning av dessa foremal kan namnas slamgjutning, pressning av pulver och strangpressning. Salunda kan roret exempelvis framstallas genom lamp-hg form av strangpressning av pulverformig aluminiumoxid, medan andtillslutningsplattorna kunna framstallas genom sammanpressfling av pulverformig aluminiumoxid i en van-hg dubbelverkande matrispress. Rorets andar bora givetvis vara i huvudsak plana, sit att de — 11873.73 —3 ansluta sigpâ ett tillfredsstallande Satt till de plana ytorna hos de hada andtillslutningsplattorna. Man belagger darefter antingen var och en av de hada andtillslutningsplattorna eller rorets bada andar med ett tunt, kontinuerligt skikt av pulver, vars sammansattning i huvudsak motsvarar sammansattningen hos andtillslutningsplattorna och roret, varefter man sammanfor de olika delarna, sã att deras samverkande ytor ansluta till varandra och bilda en fogyta. According to a particular embodiment of the present invention, one can easily effect a connection of closing plates to the open spirits of a pipe piece, these parts having been manufactured in the foreground of powdered alumina. (or beryllium oxide and / or magnesium oxide) to a suitable form. Procedures for forming these molds include slurry casting, powder pressing and extrusion. Thus, the tube can be produced, for example, by lamp-like form of extrusion of powdered alumina, while the duct closure plates can be produced by compressing powdered alumina in a standard double-acting matrix press. The spirits of the rudder should, of course, be substantially planar, provided that they - 11873.73 —3 connect in a satisfactory manner to the planar surfaces of the had duct closure plates. Then either each of the hot duct connection plates or the bath ducts of the rudder are coated with a thin, continuous layer of powder, the composition of which substantially corresponds to the composition of the duct connection plates and the tube, after which the various parts are joined together so that their cooperating surfaces connect. and form a joint surface.

Den erhallna sammansatta kroppen underkastas darefter inverkan av tryck, sa att pulverskiktet eller -belaggningen sammanpressas. Det anvanda trycket fir icke av kritisk betydelse, sa lange det är tillrazkligt hOgt for att sakerstalla fortatning av pulverbelaggningen under den efterfoljande brarmingen. Vid branningsbehandlingen utsatter man lampligen forst de sammanforda delarna for inverkan av en temperatur av minst 1600° C under minst 10 minuters tid, sa att pulverbelaggningen smaller och binder samman de enskilda delarna till ett sammanhangande foremal. Man genomfor darefter lampligen ytterligare bran-fling av det sammansatta fOremalet vid hogre temperatur, minst 1700° C, sä att den i det forsta steget bildade fOrbindningen eller fogen blir vakuumtiit. Under detta ytterligare branningssteg anvander man lampligen en atmosfar, som icke är reaktiv i forhallande till de sammanfogade delarna. The resulting composite body is then subjected to the action of pressure, so that the powder layer or coating is compressed. The pressure applied is not critical, as long as it is sufficiently high to ensure condensation of the powder coating during the subsequent bracing. During the burning treatment, the joined parts are first exposed to the influence of a temperature of at least 1600 ° C for at least 10 minutes, so that the powder coating narrows and binds the individual parts together into a coherent form. Further combustion of the composite article is then suitably carried out at a higher temperature, at least 1700 ° C, so that the connection or joint formed in the first step becomes vacuum-free. During this further firing step, an atmosphere which is not reactive in relation to the joined parts is suitably used.

Uppfinningen beskrives nfirmare medelst foljande utforingsexempel. The invention is further described by the following working examples.

Man framstallde ett ror bestaende i huvudsak av aluminiumoxid, innehallande 0,25 viktprocent magnesiumoxid, med en ytterdiameter av 6,35 mm och en vaggtjocklek av 0,79 mm, genom att pa lampligt satt blanda de bada metalloxiderna i angivna proportioner och strangpressa den lOsa blandningen. Det erhallna obehandlade foremalet brandes darefter i en atmosfar av vatgas med daggpunkter —51° C vid 1900° C under 1000 minuters tid for att fOremalet skulle fortatas. Man framstallde separat en plan platta med diametern 6,35 mm och samma sammansattning som roret genom att sammanpressa den lOsa blandningen i en dubbelverkande matrisforsedd press under ett tryck av 775 kp/cm2. Den obehandlade kroppen brandes darefter under samma betingelser, som anvandes vid branning av roret. Man sammanf5rde darefter rOret och plattan efter att ha anbringat en belaggning ay ett lost pulver av den i det foregaende angivna grundsammansattningen pa en yta av plattan. Ett tryck av 70,3 kp/cm2 anbringades darefter pa plattan, sa att denna pressades tatt mot den med plattan samverkande anden av roret. Det sammansatta fOremalet upphettades darefter, fortfarande under inverkan av tryck, i luft till 1600° G under 10 minuters tid. Efter kylning brandes det erhallna sammansatta foremalet ytterligare vid 1900° C under 1000 minuters tid i vatgas med en daggpunkt av —51° C. Den branda sammansatta kroppen kyldes darefter i ugn. Sedan den erhallna keramiska kroppen avlagsnats frau ugnen visade den sig vara enhetlig och sammanhangande samt uppvisa i huvudsak samma sammansattning helt igenom, varjamte fogen mellan de tvâ styckena var fri frail sprickor och porer. A tube consisting mainly of alumina, containing 0.25% by weight of magnesium oxide, having an outer diameter of 6.35 mm and a rock thickness of 0.79 mm was prepared by conveniently mixing the two metal oxides in the stated proportions and extruding the 10 the mixture. The resulting untreated form is then fired in an atmosphere of hydrogen gas with dew points — 51 ° C at 1900 ° C for 1000 minutes to allow the form to proceed. A flat plate with a diameter of 6.35 mm and the same composition as the rudder was separately produced by compressing the 10a mixture in a double-acting matrix press under a pressure of 775 kp / cm 2. The untreated body is then burned under the same conditions as used in burning the rudder. The tube and plate were then combined after applying a coating of a loose powder of the foregoing base composition to a surface of the plate. A pressure of 70.3 kp / cm2 was then applied to the plate, so that it was pressed against the spirit of the tube cooperating with the plate. The composite was then heated, still under the influence of pressure, in air to 1600 ° C for 10 minutes. After cooling, the resulting composite is further fired at 1900 ° C for 1000 minutes in water gas with a dew point of -51 ° C. The fired composite body is then cooled in an oven. After the resulting ceramic body was removed from the furnace, it was found to be uniform and cohesive and to have essentially the same composition throughout, and the joint between the two pieces was free of fractures and pores.

Claims

Patent claim:

A process for producing a cohesive ceramic body, consisting of alumina, magnesia and / or characterized in that two or more suitably shaped parts are assembled, consisting of one or more of these oxides, wherein they are facing each other. the surfaces of adjacent parts cooperate to form a sealing joint and a continuous layer of a powder having substantially the same composition as the parts are applied between the adjacent surfaces of each pair of cooperating joint surfaces, and apply pressure to the joined parts, so that the powder layer is compressed, after which the joined parts are burned, while these are kept under pressure for a time and at a temperature sufficient for formation of a continuous joint between each pair of these parts, the firing, if desired, being continued until these fogar aven aro vakuumtata.

A method according to claim 1, characterized in that the joined parts are fired for at least 10 minutes at a temperature of at least 1600 ° C to form a cohesive joint Indian each pair of parts.

3. A method according to claim 1, characterized in that the joined parts are fired for at least 100 minutes at a temperature of at least 1700 ° C to form a vacuum sealed joint between each pair of the parts.

4. A method according to any one of patent claims 1-3, characterized in that the joined parts are burned in an atmosphere which is not reactive in relation to the parts.

5. A method according to claim 1, characterized in that the joined parts are first burned for at least 10 minutes at a temperature of at least 1600 ° C to form a continuous connection between each pair of parts, after which the joined parts burned on this salt thereafter further fired for at least 100 minutes at a temperature of at least 1700 ° C, so that these continuous compounds become vacuum-sealed.

6. A method according to claim 5, characterized in that the parts joined together in a first stage are found to be a further 47,373 - for a period of 100-1000 minutes at a temperature of 1800-1900 ° C.

7. A method according to claim 5 or 6, characterized in that the pressure is relieved of Iran the parts joined together in a first step to burn them further.

8. A method according to any one of claims 5-7, characterized in that in a first stage the joined parts burn together are further burned in an atmosphere which is not Kr reactive in relation to the parts.

9. A process according to any one of claims 4-8, characterized in that the non-reactive atmosphere consists of water gas with a dew point not higher than -40 ° C.

10. A method according to any one of claims 1-9, characterized in that the powder layer is applied as a thin, cohesive coating on at least one of the joint surfaces of each pair of cooperating joint surfaces.

11. A method according to claim 10, characterized in that the continuous coating of the powder is applied with a thickness not greater than 2.54 mm. Request Publication Mar: