1.) What is Metglas?
Metglas is an amorphopus metal, Amorphous metals do not have crystalline structure like other magnetic materials. All the atoms in an amorphous metal are randomly arranged, thus giving it a higher resistivity (about three times) value than that for crystalline counterparts. Amorphous alloys are prepared by cooling the melt at about million degrees per second. This fast cooling does not give the atoms enough time to rearrange into stable crystalline form. As a result one gets metastable amorphous structure. Because of the absence of crystalline structure amorphous alloys are magnetically soft (lower coercivity, lower core loss, higher permeability,…). High resistivity gives lower loss at higher frequencies. The losses are among the lowest of any known magnetic materials.
2.) Can Metglas Brazing Foil be used to join steel plates?
Because of the various melting points for different Metglas Brazing Foil Alloys and steel products, it is possible to use Metglas products in this application.
You will need to contact us with specifics for the metals you are trying to join before we can give a definitive answer.
3.) What are the sizes and shapes of the Metglas products?
Metglas products are cast in ribbon form. Width and thickness of the ribbons are alloy dependent ranging from .65 mils (16 microns) to 3 mils (75 microns) in thickness and a maximum width of 8.4 inches (215 mm). The material is flexible (the edges are sharp), it can be wound, punched, stamped, laser etched, EDM’d, stacked and laminated or slit.
4.) Does Metglas Produce a Brazing Powder?
Metglas Brazing Foil is 100% high purity alloy that does not use any caustic bonding agents or chemicals to create the bond. These impurities tend to leave voids and gaps in the bonded surface which may result in joint failure.
Metglas currently only produces our brazing filler metals in a ribbon form with many sizes and alloy compositions available to the consumer.
Currently, it is not available as a powder.
5.) If I use Metglas Brazing Foil in my EGR Cooler design, what kind of design advantages can I expect?
Metglas Brazing Foil allows you the flexibility to modify your design away from the standard shell/tube structure to a more compact layered plate/fin EGR Cooler structure. This plate/fin design provides space savings and the use of Metglas Brazing Foils to join the layers provides a more robust construction compared to welded joints or those made with brazing pastes or powders.
6.) If I switch from using brazing powder to Metglas Brazing Foil for joining steel plates and fins in my automotive heat exchanger design, can I expect to have better joint strength?
Metglas Brazing Foil exhibits the highest surface area per joint. The properties of the material allow a high heat transfer rate per cross-section and can demonstrate up to 3X the shear strength of joints made with similar brazing powders & pastes.
7.) I am brazing stainless steel using Nickel-based brazing paste in my current automotive design and am experiencing furnace life longevity concerns – should I expect better furnace life if I use Metglas Brazing Foils instead?
Yes, the furnace life should be greatly enhanced since the Metglas Brazing Foil eliminates the need for binders. These binders can erode the brazing furnace surfaces requiring furnace repairs more quickly. Metglas Brazing Foil also has infinite shelf life compared to some pastes that need to be mixed then promptly used.
8.) We have a very intricate engine design that requires metal joining and during my production cycle, we are over-spraying (and subsequently wasting) a lot of brazing powder. Is there a way to reduce the amount of waste I am experiencing with my brazing materials?
Metglas Brazing Foil allows for accurate and precise lay-down of brazing materials on the surfaces that require joining – this process is much more efficient since the brazing material is only applied to the surfaces to be brazed without excess. Also, Metglas Brazing Foil is able to be cut into precise shapes (known as “preforms”) that can be applied to A-symmetrical surfaces that require brazing.
9.) What of is the best amorphous material for shielding a large magnetic field?
Of all the amorphous magnetic materials we produce, METGLAS 2605CO is the best magnetic shielding material for shielding a large magnetic field. If a large field is involved, you may have to wrap your cables with multiple layers.
10.) What is the best alloy for flux gate magnetometers?
Our 2714A material with longitudinal anneal is best suited for the flux gate magnetometer.
11.) How is 2826MB sold?
The 2826MB material has a nominal thickness of 1.2mils (30 microns). The maximum width is 2.0 inches (50mm) and the material is sold based on volume. The minimum order quantity is 1 kg.
12.) Can I get a micrographs of metallic glasses?
We are unable to offer you a micrograph of a metallic glass alloy. Such photos are, in fact, rare. The reason is that metallic glass alloys have amorphous, or non-crystalline, atomic structures. This is in contrast to the perfectly ordered, crystalline atomic structure in traditional metals. As a result, metallic glass alloys are void of microstructure in the traditional metallurgical sense. The micrograph of a metallic glass is a plain, featureless image. Hence, they are rarely recorded. The reasons for the featureless metallurgical structure are as follows.
Micrographs of crystalline alloys generally exhibit three distinct features. The most prominent of these features is the grain boundary, where one region of perfectly ordered atoms meets, but is not perfectly aligned with, another region of perfectly ordered atoms. The grain boundary, which is situated at the interface of the two perfectly ordered regions, is the result of the mismatch. Metallic glasses have no crystalline structure. Hence, there are no mismatched interfaces and no grain boundaries.
A second feature of traditional metallurgical structures is the contrast between the primary and secondary phases, that is, between regions with different chemistries and/or structures. Metallic glasses are single phase, solid solutions. Hence, there are no secondary phases.
A third feature that may be present in traditional microstructures is a crystal defect such as a twin or a dislocation. With no crystalline structure, the metallic glass do not possess such defects.
13.) What is the best material for making a wind powered generator?
We can suggest a Metglas product based cut core made from our 2605SA1 alloy called powerlite c-cores. These cores would be an excellent choice for any alternative energy inverter designs.
14.) Do you have a brazing foil with a low melting point of 100 deg c?
METGLAS, Inc produces no brazing foil or solder that can be used for joining at 100C.
15.) What are all the mechanical properties of Metglas2605SA1?
- Vicker’s hardness: 900 (with 50g load)
- Yield Strength: > 7×10^8 N/m^2
- Elastic modulus: 100-110 GPa
- Poisson’s ratio: 0.3
- Thermal expansion coefficient: 7.6 ppm/Centigrade
16.) Which Metglas product alloy has the highest permeability?
- METGLAS 2714A ribbon which has the highest permeability, exceeding that of crystalline Supermalloy
17.) What sort of annealing (transverse, longitudinal, zero field, etc…) do you recommend for low field, DC shielding applications?
Depending on the direction of the magnetic field you want to shield in a shielding material configuration you choose, annealing is different. Sometimes no annealing is needed. For specific help with your application please submit a technical inquiry describing your basic configuration.
18.) How manageable is your material after annealing. I plan to wrap annealed foil around a cylindrical form to get my cylindrical shield – will the tape be able to tolerate this?
If you anneal at low temperature (~200 C), our material is quite manageable.
19.) Can you please explain pack factor?
Pack factor is the percent volume (or fraction) occupied by the magnetic material in the core. Thicker laminations exhibit higher pack factor. Our material, with max thickness of 25 um, exhibits a pack factor in the range of 82~88%. The pack factor is also proportional to the width of ribbon. Wider strips exhibit lower pack factor relative to narrow strips. C and E cores are manufactured from narrow strips hence the core pack factor may be >84%.
20.) I would like to know more about anisotropy of METGLAS 2605SA1, does it occur at all, and if it does, how does it effect core losses?
As-cast METGLAS 2605SA1 ribbon has a magnetic anisotropy along the ribbon length direction (induced by casting), which can be changed by heat-treatment. For example, by applying a magnetic field along the ribbon length direction, you can increase the degree of the cast-in anisotropy. The effect of the anisotropy on core loss depends on the size and direction of the magnetic anisotropy. This is a general property of a magnetic material and it is recommend that you read, for example, the book “Physics of Magnetism” by S. Chikazumi (John Wiley & Sons, New York; 1964).
21.) What is the permeability of 2714A?
Our METGLAS 2714A ribbon can achieve a permeability of 100,000. The ribbon thickness is about 18 micron and we can supply up to 50 mm (2 inch) wide ribbon.
22.) What is the thermal conductivity of METGLAS2605SA1?
The thermal conductivity of this material is 9 W/m-degree C.
23.) What is the difference between A and B grade brazing alloys?
Grade A has rigid tolerances of ribbon width and thickness. Grade B has larger variations in these parameters. Both grades have the same composition and the composition variations relative to the nominal composition.
24.) Why should I buy Metglas vs. Ferrite Cores?
METGLAS alloys can be annealed to obtain square, round or completely sheared BH loops. This is not the case with ferrites. Amorphous alloys can give linear, sheared BH loops which are useful in current measuring devices. Many of the amorphous alloys have higher saturation induction and Curie temperatures. Higher saturation induction translates into smaller core. Higher Curie temp makes it possible to use the amorphous cores at higher operating temperatures.
25.) How many years have Metglas products been provided commercially?
Metglas products originated in Morristown, NJ, USA in 1972. They were produced for some time in Parsipany, NJ, USA and since 1989, in Conway, SC, USA.
26.) Normally I would degauss shields with an AC current loop whose magnitude is gradually brought to zero. Does Metglas alloy respond to degaussing in the same way that Mu-metal does?
Yes, you can degauss this material just as you do for a mu-metal. If you could achieve a near-zero remanence (e.g. via transverse field annealing – meaning your operational or shielding field direction is orthogonal to the annealing field), you probably do not need degaussing.
27.) For shielding purposes, how does Metglas 2714A alloy compare to MuMetal?
Generally speaking our METGLAS 2714A alloy is better than MuMetal; it can have the highest permeability ever achieved among any soft magnetic material and has resistance (magnetically) against any mechanical shock. To achieve a good shielding factor, one may have to make the inner cylinder diameter as small as possible with the outer cylinder diameter as large as possible if you use two cylinders.
28.) What is the thermal conductivity of your alloys?
Thermal conductivity of Metglas 2605SA1, SC, CO and S3A is about 9 W/m-Centigrade for 20-100 Centigrade. We do not have data on other Metglas alloys. However, all of our materials have electrical resistivities (inverse of electrical conductivities) of 120-140 microOhm-cm, indicating the thermal conductivities of these alloys are about the same.
29.) What are the advantages of using Metglas Brazing Foils material in an automotive metal substrate versus brazing powders?
Metglas foils allows for better joint strength – exhibiting nearly 3X the shear strength of a powder brazed joint. The properties of the metallic brazing foil also allow for more precise lay-down and reduced waste of materials. Other advantages include: contaminant free brazing, virtually reject-free joints, and unlimited shelf life.
30.) How long does it take to produce custom parts?
Customer core designs depend on on specifications provided. For customer designs please enter a sample or technical request with as much detail about the operating parameters of you design as possible.