SE204588C1

SE204588C1 -

Info

Publication number: SE204588C1
Application number: SE60561A
Authority: SE
Priority date: 1961-01-20
Filing date: 1961-01-20
Publication date: 1966-05-24
Also published as: US3223600A; DE1260264B; US3055812A; FR1310997A; GB961251A; DE1202607B

Description

Uppfinnare: B I Andersson Foreliggande uppfinning avser elektrolytisk ytbehandling, narmare bestamt palaggning av en metall ur en elektrolyt pa en metallisk yta, exempelvis forkromning och fornickling. Andamalet med uppfinningen Sr att astadkomma en metod som ger ett utfallt metallskikt som liar god vidhaftning till underlaget, som joke Sr sprat eller porost, och som har en jamn yta. Uppfinningen avser framst behandling av innerytan av rör med cirkulart tvarsnitt speciellt mycket klena rar, men kan. Sven tillampas vid invandig och utvandig be-handling av ror med annan tvarsnittsform, liksom aven vid ythehandling av andra metallforemal, exempelvis plat. Inventor: B I Andersson The present invention relates to electrolytic surface treatment, more particularly to the application of a metal from an electrolyte to a metallic surface, for example chromium plating and nickel plating. The object of the invention is to provide a method which gives a precipitated metal layer which gives good adhesion to the substrate, which joke is sprayed or porous, and which has a smooth surface. The invention mainly relates to the treatment of the inner surface of pipes with a circular cross-section, especially very small ones, but can. Sven is applied for internal and external treatment of pipes with a different cross-sectional shape, as well as for surface treatment of other metal forms, for example flat.

Sattet enligt uppfinningen kannetecknas darav, att det som katod kopplade och i huvudsak vertikalt plaeerade foremalet a ena sidan, och en som anod kopplad kropp S. andra sidan, bibringas en shdan iimsesidig rorelse att anoden ror sig i riktning nedifran och uppat relativt foremalet, varvid anoden halles sa i forhfillande till foremalet, att spalten melIan dem vidgar sig uppat, och att elektrolyten bringas att stemma uppat i spalten mellan anoden och foremilet. The method according to the invention is characterized in that the cathode connected and substantially vertically placed on the one side, and a body S. coupled as the anode on the other side, are given such a reciprocal movement that the anode moves in the direction downwards and upwards relative to the object, wherein the anode is held so in relation to the foremalt that the gap between them widens upwards, and that the electrolyte is caused to tune upwards in the gap between the anode and the foremil.

Den goda effekt, som uppnas med sattet enligt uppfinningen, torde bero pa att man reducerar de bildade gasblasornas skadliga inverkan pa palaggningsforloppet. Vid den elektrolytiska behandlingen bildas namligen ett stort antal gasblasor, som stora strOmgenomgangen i spalten mellan anod och katod, och som dSrfSr bora avlagsnas frau denna spalt sa snabbt som mojligt. Detta sker enligt uppfinningen dels genom elektrolytens stromning uppat, dels genom. gasblasornas egen tendens att stiga uppat. Foremalet som skall behandlas skall dSrför vara i huvudsak vertikalt placerat. Vid anodkroppens underkant, dar spalten mellan anod och katod Sr smalast och stramtatheten alltsa Sr stkirst, instrammar underifran en gasfri elektrolyt, som snabbt drar de i denna zon bildade gasblasorna upp- Vid anodkroppens ovre kant Si spalten bredast och stromtatheten alltsa minst, varfor de i denna zon befintliga gasblhsorna icke utova nagon sarskild skadlig inverkan pa behandlingsforloppet. DS anodkroppen under behandlingen fares uppat, kommer dess ovre parti darfor att ge upphov till en forbehandling av metallytan, medan den slutliga paliggningen, som bestammer ytfinheten, ombesOrjes av anodkroppens undre parti, som arbetar praktiskt taget utan nagon storande inverkan av gasblasor. The good effect obtained with the method according to the invention should be due to the fact that the harmful effect of the formed gas bubbles is reduced on the application process. During the electrolytic treatment, a large number of gas bubbles are formed, which are large current passages in the gap between the anode and the cathode, and which must be removed from this gap as quickly as possible. This is done according to the invention partly by the flow of the electrolyte upwards, partly by. the gas bubbles' own tendency to rise upwards. The object to be treated must therefore be placed substantially vertically. At the lower edge of the anode body, where the gap between the anode and cathode is narrowest and the tightness is therefore the narrowest, a gaseous electrolyte tightens from below, which quickly pulls the gas bubbles formed in this zone up- At the upper edge of the anode body The gas bubbles present in this zone do not have any particular detrimental effect on the course of treatment. If the anode body is raised during the treatment, its upper part will therefore give rise to a pre-treatment of the metal surface, while the final application, which determines the surface finish, is supervised by the lower part of the anode body, which operates practically without any major impact of gas bubbles.

Forkromning av innerytan av ett rar med eirkulart tvarsnitt kan enligt uppfinningen utforas pa foljande satt. Chrome-plating of the inner surface of a tube with a circular cross-section can be carried out according to the invention in the following manner.

I en likstromskrets är ett i det narmaste vertikalt stallt ror kopplat som katod. I roret Sr anordnad en anodkropp i form av en stympad kon, vilken uppbares av en isolerad kabel, tjanande dels som stromtilledare for anoden och dels sasom lyftanordning for densamma. In a direct current circuit, an almost vertically arranged rudder is connected as a cathode. Arranged in the tube Sr is an anode body in the form of a truncated cone, which is supported by an insulated cable, serving partly as a current conductor for the anode and partly as a lifting device for the same.

Den koniska anodkroppen Sr utford med sin averande sâ grov som erfordras for anslutning till den stromtillforande kabeln, och luoppens underande Sr till dimensionen sá vald, att erforderlig mangd elektrolyt kan passera genom spalten mellan konen och rorvaggen. Anodkroppens langd Sr sh vald, att konens mantelyta motsvarar den onskade stromtatheten. Anodkroppen Sr forsedd med isolerade centreringsanordningar Under elektrolysen bringas elektrolyten att str8mma i riktning uppat i spalten mellan anod och katod, under det att anodkroppen f6res uppat med en hastighet motsvarande Dupl. kl. 48 a: 5/56 2' den onskade skikttjockleken. Da anodkroppen fares uppat under behandlingen, kommer dess ovre parti att ge upphov till en forbehandling av metallytan, raedan den slutliga behandlingen bestammes av dess undre parti, dar spalten or smalast, och vilken arbetar praktiskt taget uta n flagon stora_nde inverkan av gas. The conical anode body Sr challenges with its averaging as coarse as is required for connection to the power supply cable, and the lowering Sr of the loop to the dimension so selected that the required amount of electrolyte can pass through the gap between the cone and the rudder wall. The length of the anode body Sr sh chosen, that the cone's mantle surface corresponds to the desired current density. The anode body is provided with insulated centering devices During the electrolysis, the electrolyte is caused to flow in the upward direction in the gap between the anode and the cathode, while the anode body is moved upwards at a speed corresponding to Dupl. at 48 a: 5/56 2 'the desired layer thickness. As the anode body is raised during the treatment, its upper part will give rise to a pre-treatment of the metal surface, since the final treatment is determined by its lower part, where the gap is narrowest, and which works practically without the slight effect of gas.

Data rorande ovriga betingelser vid den elektrolytiska palaggningen, sasom elektrolytens sammansattning och amplig stromtathet, tillhora den kanda tekniken. Data relating to other conditions in the electrolytic application, such as the composition and electrical current density of the electrolyte, belong to the prior art.

Claims

Patent claim:

1. Set to electrolytically treat the surface of a metal fiber, characterized in that the cathode-coupled and substantially vertically placed preform on one side, and an anode-coupled body on the other hand, impart a slight "reciprocal motion that the anode moves toward the bottom" and upwards relative to the preform, the anode Mlles being in relation to the preform, the gap between them widening upwards, and the electrolyte being caused to flow upwards in the gap between the anode and the preform.

2. A kit according to claim 1, for treating the surface of tubes, characterized in that the anode takes the form of a bottom and tapered body upwards.

3. Set according to patent claim 2 for treating the inner surface of tubes with a circular cross-section, characterized in that the anode has the shape of a truncated cone. Request publications: Patents from Sweden 92 098; France 805 918; Germany. 741669, 754082; USA 2,719,820, 2,764,540.