Method for Producing Metallic Components, Corresponding Metallic Components and Kit for Carrying Out the Method

Abstract

A method is described for producing a metallic component, comprising the following steps: provision of a negative model for the component, which (i) is electrically: conductive or is rendered electrically conductive at least on the surface thereof or (ii) is porous and comprises an electrode inside, provision of a slip which comprises electrophoretically depositable metallic and optionally additionally ceramic particles, electrophoretic deposition of a layer of the particles from the slip onto the surface of the model, sintering or partial sintering of the deposited layer of particles.

1 . A method for producing a metallic component, comprising the following steps: 
 providing a negative model for the component, which is electrically conductive or is rendered electrically conductive at least on the surface thereof,    providing a slip which comprises electrophoretically depositable metallic and optionally additionally ceramic particles,    electrophoretically depositing a layer of the particles from the slip onto the surface of the model, and    at least partially sintering the deposited layer of particles.    
   
   
       2 . A method according to  claim 1 , wherein the fraction of metallic particles in the slip amounts to 50-100 wt. %, preferably 75-100 wt. %, relative to the total mass of metallic and ceramic particles.  
   
   
       3 . A method according to  claim 1 , wherein the fraction of metallic particles in the slip amounts to 100 wt. %, relative to the total mass of metallic and ceramic particles.  
   
   
       4 . A method according to  claim 1 , wherein the negative model is made of a modelling material which is electrically conductive.  
   
   
       5 . A method according to  claim 1 , wherein the negative model comprises an electrically non-conductive modelling material having arranged on the surface thereof a coating of a conductive substance.  
   
   
       6 . A method according to  claim 1 , wherein the pore size of the porous model is adapted to the particle size of the metallic and optionally ceramic particles in such a manner that, during electrophoresis, the particles cannot reach as far as the electrode inside the model.  
   
   
       7 . A method according to  claim 1 , wherein the slip of electrophoretically depositable particles comprises a dispersed powder with a monomodal, bimodal or higher modal particle size distribution, a dispersant and optionally a stabiliser.  
   
   
       8 . A method according to  claim 7 , wherein the following applies regarding the particle size distribution of the powder: 0.1 μm<d 50 <20 μm.  
   
   
       9 . A method according to  claim 7 , wherein the stabiliser is selected from the group consisting of: electrostatically stabilising stabilisers, electrosterically stabilising stabilisers and mixtures thereof.  
   
   
       10 . A method according to  claim 7 , wherein the stabiliser is selected from the group consisting of: organic and inorganic bases and acids, the salts thereof and the cations or anions thereof, complexing agents, polymers and mixtures thereof.  
   
   
       11 . A method according to  claim 1 , wherein the slip of electrophoretically depositable particles comprises a powder with a bimodal particle size distribution, wherein the particle sizes at the locations of the two relative frequency maxima of the particle size distribution are preferably in a particle size ratio of greater than 5:1 to one another.  
   
   
       12 . A method according to  claim 1 , wherein the metallic particles consist of gold, platinum, palladium, silver or alloys which contain noble metals.  
   
   
       13 . A method according to  claim 12 , wherein sintering of the deposited layer of particles or partial sintering of the deposited layer of particles is carried out in an oxygen-depleted atmosphere.  
   
   
       14 . A method according to  claim 1 , wherein sintering of the deposited layer of particles or partial sintering of the deposited layer of particles is carried out in an oxygen-depleted atmosphere.  
   
   
       15 . The method according to  claim 1 , wherein the solids content of the slip is in a range from 20 to 75 vol. % relative to the total volume of the slip.  
   
   
       16 . A method according to  claim 1 , wherein the solids content of the slip is in a range from 30 to 60 vol. %, relative to the total volume of the slip.  
   
   
       17 . A method according to  claim 1 , wherein the slip of electrophoretically depositable particles comprises a powder with a bimodal or higher modal particle size distribution, whose fraction with the largest particle size comprises spherical particles or consists of spherical particles.  
   
   
       18 . A method according to  claim 1 , wherein at least partially sintering the deposited layer of particles is carried out at a temperature which is in the range of 0.45 to 0.9 times the melting temperature or solidus temperature (in K) of the lowest melting or the sole metallic phase of the layer.  
   
   
       19 . A method according to  claim 1 , wherein the at least partially sintering of the deposited layer of metallic particles 
 (i) in order to increase strength and reduce the porosity of the layer by at least 5%, relative to the porosity before at least partial sintering, is carried out at a temperature which is in the range of 0.6 to 0.9 times the melting temperature or solidus temperature of the lowest melting or the sole metallic phase of the layer or    (ii) in order to strength, while reducing the porosity of the layer by less than 5% relative to the porosity before at least partial sintering, is carried out at a temperature which is in the range of 0.45 to 0.6 times the melting temperature or solidus temperature of the lowest melting or the sole metallic phase of the layer.    
   
   
       20 . A method according to  claim 1 , wherein any porosity remaining after the at least partial sintering is infiltrated with glass, resin, plastics material or metal.  
   
   
       21 . A method according to  claim 1 , wherein a binder is added to the slip, which binder is deposited together with the particles, and/or a binder is applied onto the deposited layer of metallic particles before the thermal or mechanical treatment.  
   
   
       22 . A method for producing a metal-based dental restoration, comprising the following steps: 
 provision of a negative model of the dental situation to be restored, which (i) is electrically conductive or is rendered electrically conductive at least on the surface thereof or (ii) is porous and comprises an electrode inside,    provision of a slip which comprises electrophoretically depositable metallic and optionally additionally ceramic particles,    electrophoretic deposition of a layer of the particles from the slip onto the surface of the model,    sintering or partial sintering of the deposited layer of particles.    
   
   
       23 . A method according to  claim 22 , wherein the model has the dimensions of the dental situation to be restored, sintering of the deposited layer of the particles proceeds on the model and the modelling material is selected such that, under the sintering conditions, the model undergoes a relative change in length of no more than 0.2%.  
   
   
       24 . A method according to  claim 23 , wherein the model is removed mechanically or chemically from the sintered layer of particles.  
   
   
       25 . A method according to  claim 22 , wherein the model has the dimensions of the dental situation to be restored, the deposited layer of the particles in question is partially sintered and optionally previously subjected to heat treatment, wherein during partial sintering or the preceding heat treatment, the modelling material shrivels or is burnt out from the metallic layer.  
   
   
       26 . A method according to  claim 22  , wherein the model has larger dimensions than the dental situation to be restored, sintering of the deposited layer of particles proceeds on the model and the modelling material is selected such that, under the sintering conditions, the volume of the model reduces at least to the dimensions of the dental situation to be restored.  
   
   
       27 . A component, in particular a dental restoration, comprising metal produced using a method according to  claim 22 .  
   
   
       28 . A kit for carrying out a method according to  claim 22  comprising: 
 metal powder, dispersant and optionally stabilizer and/or binder and/or ceramic powder for producing a slip of electrophoretically depositable particles;    an electrophoresis apparatus for the electrophoretic deposition of the particles.    
   
   
       29 . A method for producing a metallic component, comprising the following steps: 
 providing a negative model for the component, which is porous and comprises an electrode inside,    providing a slip which comprises electrophoretically depositable metallic and optionally additionally ceramic particles,    electrophoretically depositing layer of the particles from the slip onto the surface of the model,    at least partial sintering of the deposited layer of particles.