![arloy nonprecious high fusing metal arloy nonprecious high fusing metal](https://www.barthlab.com/wp-content/uploads/2010/08/Misc-PFMs.jpg)
The bonding system that is necessary to achieve optimum bonding between such alloy and porcelain is as follows in percent by weight: These alloys have been found particularly useful for dental service and are particularly effective for fusion and tight adherence to porcelain.ĮXAMPLE I _ Proportional Preferred Element Range Composition _ Nickel Balance 75.4 Chromium 10.0-15.0 13.5 Molybdenum 1.0-7.0 5.0 Aluminum 1.0-5.0 3.0 Silicon 0.5-2.0 1.0 Manganese 1.01-0.2 0.1 Iron 0-5.0 1.5 Strontium, Lanthanum and/or Zirconium individually or as a combination of Strontium and Zirconium 0.2-2.0 0.5 100.0% _ĮXAMPLE II _ Proportional Preferred Element Range Composition _ Nickel Balance 78.4 Chromium 10.0-15.0 13.5 Molybdenum 1.0-5.0 1.5 Aluminum 1.0-5.0 3.0 Silicon 0.5-2.0 1.0 Manganese 0.01-0.2 0.1 Strontium, Lanthanum and/or Zirconium individually or as a combination of Strontium and Zirconium 0.2-2.0 0.5 Tungsten 0.5-5.0 2.0 100.0% _ĮXAMPLE III _ Proportional Preferred Element Range Composition _ Nickel Balance 78.1 Chromium 10.0-22.0 13.5 Molybdenum 0.0-3.0 1.5 Aluminum 1.0-5.0 3.0 Silicon 0.5-2.0 1.0 Manganese 0.01-0.2 0.1 Strontium, Lanthanum and/or Zirconium individually or as a combination of Strontium and Zirconium 0.0-2.0 0.5 Gallium 1.0-3.0 2.0 Iron 0.0-1.0 0.3 100.0% _ĮXAMPLE IV _ Proportional Preferred Element Range Composition _ Nickel Balance 75.4 Chromium 10.0-15.0 13.5 Molybdenum 1.0-7.0 5.0 Aluminum 1.0-5.0 3.0 Silicon 0.5-2.0 1.0 Manganese 1.01-0.2 0.1 Tungsten 0-5.0 1.5 Strontium, Lanthanum and/or Zirconium individually or as a combination of Strontium and Zirconium 0.2-2.0 0.5 100.0% _ĮXAMPLE V _ Proportional Preferred Element Range Composition _ Nickel Balance 75.4 Chromium 10.0-15.0 13.5 Molybdenum 1.0-7.0 5.0 Aluminum 1.0-5.0 3.0 Silicon 0.5-2.0 1.0 Manganese 1.01-0.2 0.1 Iron 0-2.5 1.0 Strontium, Lanthanum and/or Zirconium individually or as a combination of Strontium and Zirconium 0.2-2.0 0.5 Tungsten 0-2.5 0.5 100.0% _Īll combinations of strontium, lanthanum and zirconium within the recited ranges are effective and a useful such constituent is a 50%-50% combination of strontium and zirconium.
![arloy nonprecious high fusing metal arloy nonprecious high fusing metal](https://www.kuwatapandent.com/img/7941-PFM-Fixed-Thumb.png)
Particular examples of alloys to which this invention is applicable are listed below in Examples I-V giving preferred compositions and proportional ranges in percentages by weight. The addition of a thixotropic agent such as Cab-o-Sil, maintains all powders in solution for more consistent application and improved "painting" characteristics. The essential characteristic is that the flux will react with the porcelain and with oxides which are formed on the alloy during firing of the bonding agent, to produce a low solubility, highly tenacious, adherent intermediate layer of oxides to which porcelain will adhere during subsequent application and firing. The liquid flux is a low fusing "flux" soluble in a vehicle such as glycerine or an alcohol. _ Proportional Preferred Constituent Range Composition _ Gold Powder (1.5 microns) 34.0-52.0 34.96 Hi-Life Body Porcelain 13.1-30.6 26.22 Zirconium Oxide (10 microns) 4.4-8.74 8.74 Liquid Flux Balance 30.08 _ In accordance with this invention an extremely effective bonding agent for achieving optimum bonding between a nonprecious dental alloy and porcelain is obtained from the following formulations which are painted onto the alloy in slurry form and fired to prepare the surface for bonding to procelain. An object of this invention is to provide an effective bonding agent of this type, and another object is to provide such an economical bonding agent of readily available materials. This agent must react with the porcelain and alloy during firing to produce a low solubility, highly tenacious, adherent intermediate layer of oxides on the metal to which the porcelain will tightly adhere after subsequent application and firing. An agent is required to achieve optimum bonding between the porcelain and the alloy. Nonprecious alloys which are highly effective for dental use are described in copending commonly assigned application for U.S. Dental restorations often require fusion of porcelain to a dental alloy which must be resistant to tarnish, oxidation and corrosion in a human oral environment or, in other words, is biocompatible.