Method of producing precious metal alloy objects

Abstract

The present invention provides a method for manufacturing a biocompatible precious metal alloy object. According to a first aspect melting of alloying elements and casting of the biocompatible precious metal alloy are carried out in a process chamber ( 11 ) being provided with a process gas of predetermined composition. A burning flame ( 19 ) of a hydrocarbon-containing gas provides low oxygen and water content. According to a second aspect post-processing of a precious metal alloy is made in atmosphere provided by the process gas to form the biocompatible precious metal alloy object. The biocompatible precious metal alloy object manufactured according to the invention has a low probability of causing sensitisation when in contact with the human body.

1 - 17 . (canceled) 
     
     
         18 . A method for manufacturing a biocompatible precious metal alloy object made of a precious metal alloy, wherein the method comprises the step of ( 100 ) forming the biocompatible precious metal alloy object in a process chamber ( 11 ), and the step of at least during said forming ( 101 ) providing a process gas of predetermined composition in the process chamber ( 11 ), characterised in that the process gas has a water content of less than 0.005 kg H 2 O per kg of process gas and an oxygen content of less than 5%. 
     
     
         19 . The method according to  claim 18 , wherein the step of forming comprises the steps of ( 102 ) melting alloying elements together in order to form the precious metal alloy, and ( 103 ) casting the molten alloying elements of the precious metal alloy. 
     
     
         20 . The method according to  claim 18 , wherein the step of forming comprises the step of ( 111 ) post-processing the precious metal alloy in the process chamber ( 11 ) to form the biocompatible precious metal alloy object. 
     
     
         21 . The method according to  claim 18 , wherein the step of providing the process gas comprises the step of ( 104 ) combusting oxygen present in the process chamber ( 11 ) using a flame ( 19 ) that is supplied with a hydrocarbon-containing gas. 
     
     
         22 . The method according to  claim 18 , wherein the step of providing the process gas comprises the step of drying the process gas using dehydration means ( 21 ). 
     
     
         23 . The method according to  claim 19 , further comprising the step of evacuating a gas from a mould ( 15 ), and wherein the step of casting comprises the step of at least partly filling the mould ( 15 ) with the molten alloying elements. 
     
     
         24 . The method according to  claim 23 , further comprising the step of flowing an inert gas ( 8 ) through the mould ( 15 ). 
     
     
         25 . The method according to  claim 24 , wherein the inert gas ( 8 ) comprises process gas extracted from the process chamber ( 11 ). 
     
     
         26 . The method according to  claim 24 , further comprising the step of pre-heating the inert gas ( 8 ) in a pre-heater chamber ( 17 ) arranged in between a crucible ( 13 ) for melting the alloying elements and the mould ( 15 ). 
     
     
         27 . The method according to  claim 18 , wherein the step of casting comprises the step of cooling the moulded precious metal alloy in the process gas without exposing it to ambient air. 
     
     
         28 . The method according to  claim 19 , wherein the step of post-processing comprises soldering and/or welding of the precious metal alloy. 
     
     
         29 . The method according to  claim 28 , wherein the soldering is performed using a solder alloy that is manufactured a solder alloy in the process gas of the process chamber. 
     
     
         30 . A biocompatible precious metal alloy object, characterised in that the biocompatible precious metal alloy object is manufactured according to the method of  claim 18  and the bulk of the biocompatible precious metal alloy object has an oxygen content of less than 5 μg/g, preferably less than 3 μg/g and more preferably less than 1 μg/g; and a hydrogen content of less than 0.05 μg/g, preferably less than 0.01 μg/g and more preferably less than 0.005 μg/g. 
     
     
         31 . The biocompatible precious metal alloy object according to  claim 30 , wherein the biocompatible precious metal alloy object comprises at least 2% Ag. 
     
     
         32 . The biocompatible precious metal alloy object according to  claim 30 , wherein the biocompatible precious metal alloy object is a gold alloy of more than 14 carat. 
     
     
         33 . The biocompatible precious metal alloy object according to  claim 30 , wherein the biocompatible precious metal alloy is a silver alloy. 
     
     
         34 . The biocompatible precious metal alloy object according to  claim 30 , wherein the surface layer of the biocompatible precious metal alloy object has an oxygen content of less than 30 μg/g, preferably less than 20 μg/g and more preferably less than 10 μg/g; and a hydrogen content of less than 3 μg/g, preferably less than 2 μg/g and more preferably less than 1 μg/g. 
     
     
         35 . The method according to  claim 18 , wherein the step of forming comprises the step of ( 111 ) post-processing the precious metal alloy in the process chamber ( 11 ) to form the biocompatible precious metal alloy object. 
     
     
         36 . The method according to  claim 25 , further comprising the step of pre-heating the inert gas ( 8 ) in a pre-heater chamber ( 17 ) arranged in between a crucible ( 13 ) for melting the alloying elements and the mould ( 15 ).