Patent GB-383681-A (GB)
Title: Improvements in or relating to the manufacture of articles from the noble metals andtheir alloys
IPC: C22C5/00
Filed: 1932-09-09
Abstract: Moulded or shaped articles, e.g. spinning nozzles for the artificial silk industry, are made by first fashioning the article from an easily worked noble metal or noble metal alloy except silver or its alloys, and then diffusing throughout the article a further constituent or constituents to impart the desired properties, e.g. hardness, to the article.  A final shaping may be carried out after the diffusion.  The constituent, which is alloyed by diffusion to the noble metal or alloy, may be a metal, a metalloid, or a non-metallic element; nickel, rhodium, tungsten, molybdenum, silicon, carbon, boron, a mixture of boron and carbon, sulphur, and hydrogen being referred to.  For example, a duplex or triplex sheet consisting of a layer of noble metal or alloy and one or two layers of a modifying metal is moulded into shape and the article then heated until complete diffusion has occurred, or the article may be made from a single sheet of noble metal or alloy and the modifying metal deposited thereon, for example electrolytically, and the coated article heated.  Alternatively the shaped article may be heated in the vapour of a compound which will decompose to deposit the desired modifying agent on the article, diffusion either occurring simultaneously or being effected by a subsequent heat treatment. Examples of such compounds are silicon tetrachloride and silicon chloroform. Specific examples are as follows: (1) an article made from a gold-palladium alloy, e.g. 90 per cent palladium and 10 per cent gold, is heated in the vapour of silicon tetrachloride or silicon chloroform, or nickel or rhodium may be deposited electrolytically on the article which is then heated; (2) a palladium article is heated for several hours in contact with powdered silicon in an atmosphere of hydrogen; (3) articles made of palladium or high percentage palladium alloys are heated to incandescence in a stream of hydrogen.  It is stated that a mixture of boron and carbon is particularly suitable for improving articles made of palladium, and silicon for improving articles made of platinum. When sulphur is used the article may be heated in hydrogen sulphide.  To diffuse hydrogen into the article it may be made the cathode in an aqueous electrolyte.  Reference has been directed by the Comptroller to Specifications 5050/82, [Class 82, Metals and alloys], and 326,518, [Class 72, Iron &c.].ALSO:Moulded or shaped articles, e.g. bridges, palate plates, &c. in dentistry, canulas, or surgical tubes, are made by first fashioning the article from an easily worked noble metal or noble metal alloy, except silver or its alloys, and then diffusing throughout the article a further constituent or constituents to impart the desired properties, e.g. hardness, to the article.  A final shaping may be carried out after the diffusion.  The constituent which is alloyed by diffusion to the noble metal or alloy may be a metal, a metalloid, or a non-metallic element; nickel, rhodium, tungsten, molybdenum, silicon, carbon, boron, a mixture of boron and carbon, sulphur, and hydrogen being referred to.  For example, a duplex or triplex sheet consisting of a layer of noble metal or alloy and one or two layers of a modifying metal is moulded into shape and the article then heated until complete diffusion has occurred, or the article may be made from a single sheet of noble metal or alloy and the modifying metal deposited thereon, for example electrolytically, and the coated article heated.  Alternatively, the shaped article may be heated in the vapour of a compound which will decompose to deposit the desired modifying agent on the article, diffusion either occurring simultaneously or being effected by a subsequent heat treatment. Examples of such compounds, are silicon tetrachloride and silicon chloroform.  Specific examples given are as follows: (1) an article made from a gold-palladium alloy, e.g. 90 per cent palladium and 10 per cent gold, is heated in the vapour of silicon tetrachloride or silicon chloroform, or nickel or rhodium may be deposited electrolytically on the article which is then heated; (2) a palladium article is heated for several hours in contact with powdered silicon in an atmosphere of hydrogen; (3) articles made of palladium or high percentage palladium alloys are heated to incandescence in a stream of hydrogen.  It is stated that a mixture of boron and carbon is particularly suitable for improving articles made of palladium, and silicon for improving articles made of platinum.  When sulphur is used the article may be heated in hydrogen sulphide.  To diffuse hydrogen into the article it may be made the cathode in an aqueous electrolyte.  Reference has been directed by the Comptroller to Specifications 5050/82, [Class 82, Metals and alloys], and 326,518, [Class 72, Iron &c.].ALSO:Moulded or shaped articles are made by first fashioning the article from an easily worked noble metal or noble metal alloy, except silver or its alloys, and then diffusing throughout the article a further constituent or constituents to impart the desired properties, e.g. hardness, to the article.  A final shaping may be carried out after the diffusion. The constituent which is alloyed by diffusion to the noble metal or alloy may be a metal, a metalloid, or a non-metallic element; nickel, rhodium, tungsten, molybdenum, silicon, carbon, boron, a mixture of boron and carbon, sulphur, and hydrogen being referred to.  For example, in making a bowl, a duplex or triplex sheet consisting of a layer of noble metal or alloy and one or two layers of a modifying metal is moulded into shape and the article then heated until complete diffusion has occurred, or the bowl may be made from a single sheet of noble metal or alloy and the modifying metal deposited thereon, for example electrolytically, and the coated article heated.  Alternatively, the shaped article may be heated in the vapour of a compound which will decompose to deposit the desired modifying agent on the article, diffusion either occurring simultaneously or being effected by a subsequent heat treatment. Examples of such compounds are silicon tetrachloride and silicon chloroform.  Specific examples given are as follows: (1) an article made from a gold-palladium alloy, e.g. 90 per cent palladium and 10 per cent gold, is heated in the vapour of silicon tetrachloride or silicon chloroform, or nickel or rhodium may be deposited electrolytically on the article which is then heated; (2) a palladium article is heated for several hours in contact with powdered silicon in an atmosphere of hydrogen; (3) articles made of palladium or high percentage palladium alloys are heated to incandescence in a stream of hydrogen.  It is stated that a mixture of boron and carbon is particularly suitable for improving articles made of palladium, and silicon for improving articles made of platinum.  When sulphur is used the article may be heated in hydrogen sulphide.  To diffuse hydrogen into the article it may be made the cathode in an aqueous electrolyte.  Applications referred to are the manufacture of spinning nozzles for the artificial silk industry, bridges, palate plates &c. in dentistry, jewellery and canulas or surgical tubes. Reference has been directed by the Comptroller to Specifications 5050/82, [Class 82, Metals and alloys], and 326,518, [Class 82 (i), Metals, Extracting &c.].