SI23417A - Improved process of manufacturing and chemical composition of silver-palladium dental alloy with 64 weight percent of silver - Google Patents

Abstract

The invention refers to improved process for manufacturing of Ag-Pd dental alloy and to a new chemical composition of it with 64 w% of Ag. The technical problem solved with this invention is manufacturing of dental alloy with chemical composition of 2.0 w% Au, 25.0 w% Pd, 64.0 w% Ag, 8.0 w% Cu and less than 0.7 w% Zn. In the presented example the exact sequence of technological processes is defined which enables the making of Ag-Pd dental alloy plates with required chemical composition, dimensions and properties. The process of manufacturing is composed of melting and casting in iron mould, cold reforming of casted performs: profiled rolling, intermediate re crystallization glowing, flat rolling, final polish rolling and cutting of strips into defined plate size.

Description

Improvement of the process of manufacturing and chemical composition of silver-palladium dental alloy with 64 weight percent silver

It is an object of the invention to improve the process for the manufacture and chemical composition of high-content silver (Ag) silver-palladium (Ag-Pd) dental alloy. The mass fraction of Ag in the alloy is above 64 m. % which has excellent mechanical properties. This alloy has the following required improved chemical composition: 2.0 wt% Au, 25 wt% Pd, 64 wt% Ag, 8 wt% Cu, Zn <0.7 wt%, which can fluctuate +/- 2% in an individual components. A technical problem solved by the dental alloy fabrication process is the manufacture of these alloys with the required chemical composition and the consequent achievement of the required properties. The Ag-Pd dental alloy must have, in addition to the required chemical composition, an adequate melting interval (between 960 ° C-1060 ° C) and a casting temperature (1150 ° C-1200 ° C), a hardness of about 215 HV (for improved -p) and 130 HV (for soft state -m), elongation of about 20% (p) and 22% (m), tensile strength R _m 825 N / mm ² (p) and 685 N / mm ² (m), and plasticity limit around 660 N / mm ² (p) and 490 N / mm (m). Other requirements are related to the following tolerances: melting interval + / 10 ° C, casting temperature +/- 30 ° C, hardness +/- 10 HV, elongation +/- 2%, while tensile strength and plasticity limit can only drop by 10 N / mm ² according to the required values. The Ag-Pd dental alloy must meet all the requirements in dental technology, where material is used for fixed crowns and longer multi-link bridges (standard EN ISO 9693: 2000). Otherwise it can also be used for milling / telescopes, overhead - castings, etc.

All of the above requirements can be achieved by the described improved technological procedures, the most important of which is the thermo-mechanical treatment of Ag-Pd dental alloy, where the desired required properties are achieved with the right combination of mechanical and thermal treatment at the required dimensions.

Today, many technological processes are known, which are the basis of the processing technique, which differ in their function partially or substantially, and enable the production of various forms of objects, including silver-palladium dental alloys. They can generally be divided into four main groups:

- primary design comprising refinement and casting, etc .;

- cold forming comprising rolling, profile rolling, flat rolling, etc .;

- refinement, or so. heat treatment comprising the improvement of: exterior by surface treatment or internal by thermal treatment;

- splitting comprising shearing, cutting, trimming, etc.

The characteristics of individual technological processes are as follows:

When casting, pour molten metal into a mold cavity in which it solidifies and retains its shape. In this way, the mold gets the final shape that will be retained for further processing and use. In a simple and economical casting process, we make a shape that we couldn't otherwise have, or we could make it with difficulty. Castings replace forged products, although they have better mechanical properties due to their fine-grained structure. Castings, on the other hand, have the same strength in all directions, which has a beneficial effect on subsequent mechanical treatment.

The basis of cold forming is limited to plastic deformation transformation methods, in which the microstructure of the material being transformed is changed, whether it is a cast or already transformed microstructure. These methods include rolling, which is a process of continuous transformation of a metal between two cylindrical pressure surfaces (cylinders) rotating in opposite directions, with a distance less than the thickness of the rolled object. The material moves through the workspace due to friction between the cylinders and the roller; in doing so, the roller extends in the direction of the main load of the compression, but at the same time it extends perpendicularly and longer. The rolling deformation should be greater in the direction of minimum resistance (in the direction of rolling). As the time unit enters between the cylinders the same amount of material as it exits, and the cross-section of the opening between the cylinders decreases in the direction of rolling, the speed of the cylinder increases in approximately the same proportion as its thickness decreases. We can briefly summarize the following general characteristics of rolling:

- the exit velocity of the cylinder is greater than the constant circumferential velocity of the cylinders,

- the plastic deformation process takes place between cylinders having the same diameter and the same rotational speed,

- the axes of the cylinders belonging to one frame are parallel and lie in the rolling plane,

- Adjust the opening between the cylinders by adjusting the cylinders (with special screw spindles manually, mechanically or hydraulically).

- the rolling direction is perpendicular to the rolling plane,

- the contact arc surfaces across the width of the roller, the roller opening and the jump limit the forming area in which the material is plastically deformed.

Profile rolling is used in the production of various profiles, where the change of the entire cross section of the roll has an important role. The changes in the thickness and width of the roller are determined by the shape and size of the profile enclosed by the rollers. The production of profiles is faster and more economical, the greater the ratio of the cross-section of two successive plugs. For this reason, it is very important to determine, as a rule, the sizes and number of individual plugs required to complete the final profile. With a small number of plugs, the rolling time can be shortened, but this number of plugs or passes of the roller through the rolling hole is limited by the maximum allowable deflection deflection interval between the individual plugs.

Heat treatment is a process of heating, milling, cooling and subsequent annealing, which achieves the intended properties or microstructural state of the alloy. It consists of: heating to a certain temperature, isothermal holding for a fixed time, and various rapid cooling. In this way, the unbalanced state of the microstructure resulting from cooling is changed in a controlled manner. Heat treatment of metallic materials can greatly improve an individual property or several properties at once and achieve a useful combination of properties. The heat treatment is aimed at reducing the internal stresses of the metal, releasing the hardening due to cold deformation and increasing the ductility by repairing and recrystallization, changing the microstructure or improving the microstructure of homogeneity. The possible heat treatments depend on the characteristics of the structure of the material (constitution) as can be seen in their phase diagram. The goals of homogenization or diffusion mourning are to achieve a homogeneous or uniform chemical composition in the microstructural components. The goals of voltage insult are to reduce internal stresses in the material. These insults are carried out at temperatures at which the microstructure of the material and thus its other properties change as little as possible. Recrystallization mourning is a heat treatment that softens materials that have been hardened by cold plastic deformation. Solvent insults dissolve the secretions and obtain a homogeneous solid solution.

The purpose of the technological separation process, which includes shearing, is to separate one part of the material (sheet) from the other part, or to prepare the material for further transformation or to obtain a definite final shape. There are two methods of shearing: shearing on scissors and shearing with special cutting tools. In the first case of shearing, we are talking about an open cut between the cutting edges of two knives, which can be straight or circular. Known open cut procedures are trimming and trimming. In the second case of shearing, we have a closed cut formed by individual parts of the tool. These cutting methods include cutting, punching, trimming and cutting.

The above described methods describe methods and influential process parameters that allow the production of certain dimensions and properties of different types of semi-finished products, while the solution of the correct sequence of technological procedures for the production of silver-palladium dental alloys is not given. There is also no specific solution for the control of thermo-mechanical treatment of Ag-Pd dental alloy, which can be achieved with the desired chemical properties of the desired properties of these dental alloys.

A technical problem solved by the invention is the improved chemical composition and manufacturing process of Ag-Pd dental alloy. In the manufacturing process, the examples provided show the exact sequence of technological processes by which the Ag-Pd dental alloy can be manufactured with the required properties. The solution to the technical problem enables the reliable achievement of the quality of Ag-Pd dental alloy.

The following is a process for manufacturing an Ag-Pd dental alloy according to the invention with a detailed technological description for each individual manufacturing step separately:

(i) melting of feedstocks - pre-alloys (Ag / Pd, Cu / Zn) and other components: Au, Ag, Cu and Pd;

(ii) casting molten pre-alloys (Ag / Pd, Cu / Zn) into the metal mold and Ag / Pd dental alloys into the metal mold;

(iii) cold forming processes of cast preforms of pre-alloys (Ag / Pd, Cu / Zn) and Ag / Pd dental alloys: profile rolling and rolling;

(iv) thermal treatment of intermediate Ag / Pd dental alloy semi-finished products: recrystallization annealing with appropriate regimes in the selected atmosphere;

(v) trimming of Ag-Pd dental alloy tiles on both sides of the Scissors and stamping.

An exemplary manufacturing process for an Ag-Pd dental alloy is provided at the end of the descriptions.

(i) Ag / Pd pre-alloy

The melting of the Ag / Pd pre-alloy (50:50 wt.%) Takes place in an induction furnace at T = 1473 K in a protective atmosphere Ar (with a flow rate of 31 / min and a pressure of 1.03 bar) and represents a change in the solid aggregate state of silver and palladium into liquid z by supplying thermal energy via high frequency induction. This is based on an electronic generator that produces high frequency current (~ 170 kHz). It runs over the surface of a hollow copper conductor, which, like a coil, surrounds a vertically standing melting pot with some windings. The current generates an alternating electromagnetic field with the highest concentration of magnetic forces in the center of the graphite retort, where Ag and Pd are deposited. The electromagnetic field induces high-frequency current in metals - Ag and Pd, which heats them strongly and finally also relatively quickly.

(ϋ)

The molten Ag / Pd pre-alloy is poured into a flat metal mold of dimensions: 120 mm χ 100 mm * 15 mm. This is followed by cooling in a metal mold and then quenching immediately in water to equalize the temperature with T _V0 d _e . Prior to further thermo-mechanical treatment, the cast preform of the Ag / Pd pre-alloy needs to be further cleaned, which means flushing and brushing the casts with a mixture of water and detergent and finally drying with compressed air.

(iii)

In the case of flat Ag / Pd molded preforms with dimensions 120 mm χ 100 mm χ 15 mm, rolling in the first stage should be carried out on a rolling machine with smooth cylinders with hard surface (recommended thickness of cemented layer is at least 6 mm) , about 250 mm in diameter. This rolling is performed in 0.5 mm increments to a final □ = 0.6 mm. After rolling, the Ag / Pd preform is cut to 15 mm χ 15 mm.

(i) Cu / Zn pre-alloy

The melting of Cu / Zn pre-alloy (66:34 wt.%) Takes place in an induction furnace at T = 1273 K in a protective atmosphere Ar (with a flow rate of 31 / min and a pressure of 1.03 bar) and represents a change in the solid aggregate state of copper and zinc in liquid with by supplying thermal energy via high frequency induction. This is based on an electronic generator that produces high frequency current (~ 170 kHz). It flows over the surface of a hollow copper flow conductor, which, like a coil, surrounds a vertically • standing melting pot with a few threads. The current produces an alternating electromagnetic field with the highest concentration of magnetic forces in the center of the graphite retort, where Cu and Zn are deposited. The electromagnetic field induces high-frequency current in metals - Cu and Zn, which heats them strongly and finally also relatively quickly.

(H)

The molten Cu / Zn pre-alloy is poured into a flat metal mold 120 mm x 100 mm x 15 mm. This is followed by cooling in a metal mold and then quenching immediately in water until equilibration with T _VO de- Before further thermo-mechanical treatment, the pre-formed Cu / Zn preform has to be further cleaned, which means washing and brushing the casts with a mixture of water and detergent, and finally drying with compressed air.

(iii)

For flat Cu / Zn molded preforms with dimensions 120 mm χ 100 mm x 15 mm, profile rolling must be carried out in the first stage, which should take place on a flat cylinder with steps of 0.6 mm - 0.5 mm to the final □ = 0.6 mm. After rolling, the Ag / Pd preform is cut to 15 mm x 15 mm.

(i) Ag-Pd dental alloy

The melting of the Ag-Pd dental alloy (Ag / Pd, Cu / Zn, Au, Ag, Cu, a small tablespoon of charcoal) takes place in an induction furnace between T - 1523 K - 1573 K in a protective atmosphere of Ar (with a flow rate of 31 / min and a pressure of 1.03 bar) and represents the change in the solid aggregate state of the pre-alloys in the form of 15 mm * 15 mm tiles and other components of the dental alloy into liquid by supplying thermal energy through high frequency induction. This is based on an electronic generator that produces high frequency current (~ 170 kHz). It runs over the surface of a hollow copper conductor, which, like a coil, surrounds a vertically standing melting pot with some windings.

• · · ·

The current generates an alternating electromagnetic field with the highest concentration of magnetic forces in the center of the graphite retort, into which the necessary components of the Ag-Pd dental alloy are deposited. The electromagnetic field induces a high-frequency current in the metal, which it strongly heats and finally also relatively quickly melts.

(ϋ)

The molten Ag-Pd dental alloy is poured into a steel mold with a recommended diameter of Φ = 55 mm (so-called cone). This is followed by 1-1.5 min cooling - keeping the dental alloy in the steel mold and immediately after quenching in water until the temperature equals T _VO de · After quenching, a trim of 0.3-0.5 cm should be made on the top surface of the cast, at the point where there was a shrinkage of material. Before further thermo-mechanical treatment, the cast preform must be further cleaned, which means flushing and brushing the casts with a mixture of water and detergent and finally drying with compressed air.

(iii)

The homogeneous casting of Ag-Pd dental alloy castings on the counter casting device (castings Φ = 55 mm until the pot is filled, a small tablespoon of charcoal) must be carried out below. The melting of this dental alloy on this device takes place between T = 1523 K - 1573 K in a protective atmosphere Ar (with a flow rate of 31 / min and a pressure of 1.03 bar). Stainless steel pull-out spikes must be used to start the draw, which must be soaked in carbon paste. During casting, a clearance of 0.5 mm is required between the rod and the mold. The extraction of Ag-Pd dental alloy from the contour is performed in steps of 2-4 mm into a rod with a diameter of 2r = 9.5 mm, while cooling with water takes place immediately at the exit of the rod from the mold. To control the continuous casting process, it is necessary to install a temperature gauge on the mold in the temperature range between 1123 K-1153 K. A 2 cm long trim is to be made at the upper and lower ends at the point where the material has shrunk. Before further thermo-mechanical treatment, the cast rod has to be cleaned, which is to rinse and brush the castings with a mixture of water and detergent, and finally to dry with compressed air.

• ·

and (iv)

A continuous casting rod of 2r = 9.5 mm must be cut into pieces of 0.8 m length in the first stage. From this dimension of the square profile onwards, it is necessary to carry out a flat rolling on the bars on a rolling device, which should have flat working cylinders made of steel for improvement (in our case, we used cylinders made of material with OHV4 or DIN 86CRMOV7 mark from Metal Straight) with about 120 mm in diameter. This flat rolling should be performed up to a diameter of □ = 5.3 mm (± 0.2 mm) in 0.25 - 0.3 mm increments. This is followed by cutting the bars to 500 mm length and cleaning the surface of the bars with a soft curly MS wire brush. Due to the high internal stresses and over-hardening of the Ag-Pd dental alloy bars, recrystallization isothermal insulting of the bars is required, together with 5 pieces in a flux furnace at 1143 K at a flow rate of 200 mm / min in a protective atmosphere (H2: N2 = 80:20). After mourning is complete, allow the rods to cool slowly in air to room temperature. Before further thermo-mechanical treatment, the rods need to be cleaned again, which is to rinse and brush the casts with a mixture of water and detergent, and finally to dry with compressed air. This is followed by the flat rolling of bars with a diameter of 5.3 = 5.3 mm into a strip of thickness d = 2.8 mm (± 0.2 mm) in steps of 0.25 - 0.3 mm. Due to the re-emergence of internal stresses, the recrystallization isothermal insulting of the strips should be carried out again, 5 pieces together in a flow-strip furnace at a temperature of 1173 K at a flow rate of 200 mm / min in a protective atmosphere (H2: N2 = 80: 20). After mourning is complete, allow the strips to cool slowly again in air to room temperature. Before further thermo-mechanical treatment, the tapes need to be cleaned again, which is to rinse and brush the casts with a mixture of water and detergent, and finally to dry with compressed air. In the next step, we perform flat rolling of strips with thickness d = 2.8 mm into strips with d = 1.7 mm (+ 0.05 / -0) in steps of 0.25 - 0.3 mm. The final transformation process is poly rolling. It is rolled on a rolling device having a pole working cylinders with a diameter of about 120 mm and whose hardness must correspond to the hardness of the carbide solid (1000 HV). This requirement must be respected at this stage of transformation in order not to cause a large • * • · roughness of the Ag-Pd dental alloy roll during the rolling process due to insufficiently rigid cylinders. The rolling process is performed in two steps d = 0.2 mm into a strip of 1.40 mm (+ 0.05 / -0) thickness and 7 mm width. After rolling, the Ag-Pd dental alloy strips are cut using double-sided Scissors into tiles: 7 mm (± 0.3) x 7 mm (± 0.3) χ 1.4 mm (± 0.3).

Example completed:

Ag-Pd DENTAL ALLOY WITH 64 WEIGHT PERCENTAGE OF SILVER (2.0 m.% Au, 25.0 m.% Pd, 64.0 m.% Ag, 8.0 m.% Cu, 0.7 m.%> Zn)

Description of the manufacturing process:

1. Cabinet:

a) preliminary requirements and preparation of pre-alloys (at least in the amount of the total requirement without feces):

- Require pre-alloys Ag / Pd, Cu / Zn

- control of weathered pre-alloys

b) weigh according to the recipe:

- Aggregate joint control of Ag-Pd alloy components: Au, Ag, Pd

2. Smelter: use of dedicated graphite pots for dental alloys

a) Pre-fabrication of Ag / Pd pre-alloy:

- compression of the individual pre-alloy components: Pd and Ag

- casting in an induction furnace at T = 1473 K (in atmosphere Ar 5.0, flow Ar = 31 / min)

- pouring molten Ag / Pd pre-alloy into Fe mold 120 mm x 100 mm x 15 mm, quenching in H2O

- casting cleaning (trimming, water, detergent, brush, drying - compressed air)

- weighing

b) pre-fabrication of Cu / Zn pre-alloy:

• ·

- Alloying and casting in an induction furnace at T = 1273 K (in atmosphere Ar 5.0, flow Ar = 31 / min)

- casting of molten Ms pre-alloy in Fe mold 120 mm x 100 mm x 15 mm, quenching in H2O

- casting cleaning (trimming, water, detergent, brush, drying - compressed air)

- weighing

c) casting an Ag-Pd dental alloy into casts i.e. konige:

- alloying (loading of components into the furnace: Cu / Zn, Cu, Au, Ag / Pd, Ag, small spoon of charcoal) and casting in an induction furnace by manual mixing with a carbon rod at T = 1523-1573 K (in an atmosphere of Ar 5.0, flow Ar = 31 / min)

- casting of molten alloy into a steel mold (Φ = 55 mm)

- cooling (holding) the alloy in the steel mold 1-1.5 min in air, then quenching in water

- casting cleaning (trimming, water, detergent, brush, drying - compressed air)

- weighing

d) homogeneous casting of alloy casts, i.e. conig in the furnace:

- casting in a continuous casting furnace with final manual mixing at T = 1523-1573 K (conigs, small spoon of charcoal) in an atmosphere of Ar 5.0, flow Ar = 31 / min

- alloy extraction in Φ = 9.5 mm (extraction step 2-4 mm; cooling with H2O immediately upon leaving the mold; stainless steel pull-out soaked in C paste; 0.5 mm clearance between the rod and mold, pouring temperature indicator on the mold 1123 -1153 K)

- cut ~ 20mm beginning and end of casting

- cutting the bar to a length of 0.8 m

- casting cleaning (trimming, water, detergent, brush, drying - compressed air)

- weighing

3. Cabinet:

- casting weighing, sorting

- casting control

4. Production preparation: plastic transformation of pre-alloys and Ag-Pd dental alloys on clean and dry cylinders

a) preliminary transformation and cutting of Ag / Pd pre-alloy:

- profile rolling on a flat cylinder with steps 0.5-0.6 mm to a final □ = 0.6 mm (machine AURO 0315)

- cut to approx 15mm x 15mm

- weighing

b) Pre-conversion and cutting of Cu / Zn pre-alloy:

- profile rolling on a flat cylinder with steps 0.5-0.6 mm to a final □ = 0.6 mm (machine AURO 0315)

- cut to approx 15mm χ 15mm

- weighing

c) Plastic transformation and cutting of Ag-Pd dental alloy:

- Flat rolling of bars from Φ = 9.5 mm to □ = 5.3 (+/- 0.2) mm with steps 0.25-0.3 mm (ZC 0439 machine)

- cutting of bars to 500 mm length

- cleaning of bars with soft curly brass wire brush, water and detergent

- annealing of 5 bars together in a stream-type furnace at 1143 K at 200 mm / min in a N2 / H2 protective atmosphere

- cooling the rods in air to T _are bne

- Flat rolling of bars □ = 5.3 mm into a strip of 2.8 mm thickness (± 0.2 mm) with steps 0.25-0.3 mm (AURO 0315 machine) • ·

- insulting 5 strips together in a flow furnace at 1143 K at 200 mm / min in a N2 / H2 protective atmosphere

- cooling the straps in air to T _S0 b _no

- Cleaning strips with soft curly brass wire brush, water and detergent

- Flat rolling of tape with d = 2.8 mm into tape with d = 1.7 (+ 0.05 / -0) mm with steps 0.25-0.3 mm (machine AURO 0315)

- pouring tape rolling to a thickness of 1.40 mm (+ 0.05 / -0) and a width of 7 mm (machine AURO 0319)

- Tile cut 7 mm (± 0.3) x 7 mm (± 0.3) x 1.4 mm (+ 0.05 / -0) with ZC stamping (AURO 0429 machine)

- control of plastic processing.

Claims (20)

PATENT APPLICATIONS 1. A process for manufacturing an Ag-Pd dental alloy with 64 wt.% Ag is characterized by the fact that it consists of melting and casting, cold forming of cast preforms, heat treatment and cutting of the strip into dimension-appropriate plates. 2. The method according to the preceding claim, characterized in that the melting of the Ag-Pd dental alloy is carried out by an inductive method between T = 1523 and 1573 K in a protective atmosphere Ar (at a flow of 3 l / min and a pressure of 1.03 bar). 3. The method according to the preceding claims, characterized in that the molten Ag-Pd dental alloy is cast into a metal conical mold with 0 = 55 mm. Method according to the preceding claims, characterized in that the cast molds of Ag-Pd dental alloy in the metal molds are cooled for 1-1.5 min at room temperature and then extinguished in water. 5. The method according to the preceding claims, characterized in that a 0.5 cm cut is required on the upper surface for cast molds of Ag-Pd dental alloy with 0 = 55 mm. 6. The method according to the preceding claims, characterized in that the continuous casting of conical cast preforms of Ag-Pd dental alloy between T = 1523-1573 K into a rod of diameter 2r = 9.5 mm is required. Ί. The method according to the preceding claims, characterized in that continuous casting is carried out with a pull step of 2-4 mm at a clearance between the rod and the mold 0.5 mm. The method according to the preceding claims, characterized in that it is carried out by means of a flat roll for cast bars with 0 = 9.5 mm AgPd dental alloy. 9. The method according to the preceding claims, characterized in that it proceeds in steps of 0.25-0.3 mm to a rod diameter of 5.3 = 5.3 mm. 10. The method according to the preceding claims, characterized in that intermediate recrystallization isothermal annealing of rods of Ag-Pd dental alloy with □ = 5.3 mm is required in a flow-band furnace at 200 mm / min at a temperature of 1143 K and in a protective atmosphere. (H2: N2 = 80: 20). 11. The method according to the preceding claims, characterized in that after the insult is completed, the rods must be cooled slowly in air to room temperature and cleaned in water and detergent with a brush. 12. The method according to the preceding claims, characterized in that it is carried out by means of a flat-rolled rod of an Ag-Pd dental alloy with a diameter of 5.3 = 5.3 mm. 13. The method according to the preceding claims, characterized in that it proceeds in steps of 0.25 mm - 0.3 mm to a strip thickness of d = 2.8 mm. 14. The method according to the preceding claims, characterized in that another intermediate recrystallization isothermal insulting of an Ag-Pd dental alloy strip d = 2.8 mm is required in a flow furnace at a rate of 200 mm / min at a temperature of 1143 K and in a protective atmosphere ( H2: N2 = 80: 20). 15. The method according to the preceding claims, characterized in that after the annealing is completed, the strips should be allowed to cool slowly in air to room temperature and be cleaned in water and detergent with a brush. 16. The method of the preceding claims, characterized in that it is carried out by rolling an Ag-Pd dental alloy strip with a thickness d = 2.8 mm. Process according to the preceding claims, characterized in that it proceeds in steps of d = 0.25 mm - 0.3 mm to a strip thickness of d = 1.7 mm. 18. The method according to the preceding claims, characterized in that it is carried out by means of a polymer rolling of an Ag-Pd dental alloy strip with a thickness d = 1.7 mm. • * 19. The method of the preceding claims, characterized in that it proceeds in steps of 0.2 mm to a strip thickness of d = 1.4 mm. 20. The method according to the preceding claims, characterized in that the Ag-Pd dental alloy strip of d = 1.4 mm is to be cut into 7 mm x 7 mm χ 1.4 mm tiles. 21. The method according to the preceding claims, characterized in that the required chemical composition of the Ag-Pd dental alloy can be: 2.0 wt% Au, 25 wt% Pd, 64 wt% Ag, 8 wt% Cu, Zn <0.7 m .% fluctuates +/- 2% in each component.