15

Is there an available at home material with the melting point between 500 °C and 590 °C?

  • Plastics usually melt below 400 °C.
  • Tin and lead also below that.
  • Aluminum is melting above 600 °C.

I made a deep search around the web with no success.

andselisk
  • 37,604
  • 14
  • 131
  • 217
xchcui
  • 307
  • 2
  • 10
  • 6
    It's interesting that there appears to be no chemical element with m.p. in this range. – andselisk Mar 02 '22 at 16:34
  • 2
    As @Poutnik says a salt mix will do it. That temperature is in a range to heat-treat and process steels so some vendor of heat-treat supplies will have a salt mix available. I never worked with them so can't be more specific. – blacksmith37 Mar 02 '22 at 16:59
  • 2
    You could try contacting one of the metals suppliers that sells aluminum alloys on Amazon, and asking them if they have one that would melt in your desired temperature range. I'd suggest finding a supplier that sells on Amazon, as that tells you they are willing to sell to consumers, in small quantites. You'll need to tell them if it has to melt at a specific temperature, or if it's acceptable if it melts over a temperature range (which happens with some alloys). I can't vouch for the following company, since I've never ordered from them, but one example is https://www.onlinemetals.com – theorist Mar 03 '22 at 07:09
  • I admit, I'm a physicist and more of an engineer than a chemist, but to choose a material you need to consider what it will be used for and come into contact with. For example molten salts can be quite corrosive. If you're going to put some granules in a container to see if the container has reached a certain point while you couldn't otherwise monitor it, you'll also need to consider the heat flow in, and the heat capacity and latent heat, otherwise you will actually be recording whether it's exceeded the melting point for some time. – Chris H Mar 03 '22 at 11:28
  • The salt mixes for steel treating are generally contained in cast iron , so minimally corrosive. – blacksmith37 Mar 03 '22 at 15:52
  • 7
    What is the application? What is your budget? How much do you need? Impossible to answer without more information. – J... Mar 03 '22 at 19:33
  • 3
    In plain-speak, what are ya working on? – john Mar 04 '22 at 08:53
  • 1
    Also, what facilities do you have available? The idea of DIY alloying has come up, but do you have a furnace? – Chris H Mar 04 '22 at 13:01
  • 1
    The problem with alloys is that they often do not have a clear melting point. They start melting at the solidus temperature. But only a small fraction is melting. To get all the salloy in the liquide state, you have to heat it to a much higher temperature, called liquids point. – Maurice Mar 04 '22 at 17:30

6 Answers6

30

Temperature-indicating or thermo crayons are used by welders. These melt at specific temperatures.

Not as an endorsement, but to give you an idea of what's available, the crayons from McMaster-Carr come in these temperatures in the range you are interested in:

  • 932 °F (500 °C)
  • 950 °F (510 °C)
  • 1000 °F (537.8 °C)
  • 1022 °F (550 °C)
  • 1050 °F (565.6 °C)

Another brand name is "Tempilstik" (again, not an endorsement).

Temperature-indicating crayons are available at any welding supply.

Wayne Conrad
  • 401
  • 3
  • 6
18

It might not qualify as 'available at home' but MakeItFrom has a database with engineering material you can search:

MakeItFrom.com is a curated database of engineering material properties that emphasizes ease of comparison. It is not a datasheet dump: every listed material is an internationally recognized generic material. The data is sourced from published standards, academic literature, and supplier documentation.

To find information on a particular material, browse from the list below, or search from the menu. Aside from searching by material name, you can also search by property values. Once on a material's page, you can search for a second material for a side-by-side comparison.

This query lists all materials with a melting point between 500 and 590 degrees Celsius; mostly aluminium alloys.

There are some salts in this list on The Engineering Toolbox which qualify too and can be bought online, but e.g. silver iodide (melting point 558°C) is toxic and I would rather avoid that.

Glorfindel
  • 2,075
  • 4
  • 20
  • 28
  • 2
    The problem is that this alloy needs to either be identified (which would require elemental analysis, XRF, or powder XRD), or ordered, which manufacturers really like to do in bulk amounts, which would be an overkill for home experiment. Other than that, a good source of information. – andselisk Mar 02 '22 at 16:39
  • 3
    @andselisk a metal stockholder will supply fairly small quantities of a standard alloys, in forms they hold. The Al alloys produced by that table are mostly casting types. I'm used to machining types, and my supplier doesn't carry any of those. But in the next city there's a supplier of ingots of casting alloys that has quite a few of the listed ones. I reckon I could jump on the bike and have an ingot in my hand this afternoon. So "at home" should be doable. – Chris H Mar 03 '22 at 11:22
11
Name Formula m.p./°C
Copper(II) chloride $\ce{CuCl2}$ 498
Barium perchlorate $\ce{Ba(ClO4)2}$ 505
Potassium fluoroborate* $\ce{KBF4}$ 530
Antimony trisulfide (stibnite) $\ce{Sb2S3}$ 550
Calcium nitrate $\ce{Ca(NO3)2}$ 561
Sodium cyanide $\ce{NaCN}$ 563
Cadmium bromide $\ce{CdBr2}$ 567
Strontium nitrate $\ce{Sr(NO3)2}$ 570
Potassium periodate $\ce{KIO4}$ 582
Iron(II) iodide $\ce{FeI2}$ 592

* It is not difficult to buy it.

Ian Bush
  • 3,039
  • 1
  • 15
  • 28
Maurice
  • 28,241
  • 3
  • 29
  • 61
  • 1
    560°C for KOH is suspiciously high, compared to NaOH. I have checked Wikipedia, it says 360. – Poutnik Mar 02 '22 at 23:58
  • 2
    I even have a small bottle of strontium nitrate at home, as one does! (+1) – Ed V Mar 03 '22 at 02:28
  • 8
    OP is asking about home materials and not laboratory chemicals. – Nilay Ghosh Mar 03 '22 at 03:34
  • 2
    I don't know the specific chemistries of these, but the general problem with melting crystalline compounds is that they often contain water of crystallization and some of them will "melt" by dissolving into their own water of crystallization at a lower temperature. Also beware of toxic, corrosive and even explosive risks. Perchlorates are strongly oxidizing and Sodium Cyanide is notorious as a poison. – nigel222 Mar 04 '22 at 13:13
9

There ought to be an alloy with the desired melting point. It doesn't seem to be commercially available, but you could experiment by obtaining tin or zinc, plus copper powder (or scrap brass / bronze), and melting them together. Copper has a high melting point, tin just 232 °C and zinc 420 °C. Copper + tin = bronze and copper + zinc = brass.

The commercially available forms have higher melting points than you want. The forms with more tin or zinc than usual may not be very good in other metallurgical terms, but it's certain that there's a composition that melts at the temperature you want.

Peter Mortensen
  • 363
  • 2
  • 10
nigel222
  • 191
  • 3
  • 1
    And here's a Cu-Zn phase diagram suggesting you'll need something like 90% Zn, 10% Cu. Al-Zn (phase diagram alloys might be easier to make as you're nearer 50:50, on a flatter part of the curve, and Al is much easier to melt than Cu when you make the alloy. This time commercial alloys have a melting point that's too low – Chris H Mar 04 '22 at 13:01
  • Copper will dissolve in a liquid metal well below its melting point. Specifically from experience, in solder (lead-tin alloy in those days). Soldering-iron bits are iron coated copper. After any slight perforation of the iron coating, the liquid solder quite rapidly dissolves the underlying copper and the bit "craters" and becomes fairly useless. Uncoated bits fan be filed flat but the solder soon dissolves copper off the flat surface. – nigel222 Mar 04 '22 at 17:23
  • Good point re soldering tips. I've done that enough (and used stiff copper wire to make consumable custom tips. The acid in the flux may play a part too. I'm not sure how well copper would dissolve in zinc though, hinting more at sticking to tin (modern soldering being Sn+Cu or Sn+Ag anyway) – Chris H Mar 04 '22 at 18:25
7

As mentioned, various aluminium alloys melt in this range. Alloys and other mixtures don't have a single melting point. They melt over a temperature range between the solidus and liquidus temperatures.

For example alloy 4043 is readily available as welding wire. Solidus 573.9 °C, Liquidus 632 °C. You would need to use a phase diagram to determine the liquid fraction at intermediate temperatures.

David Billinghurst
  • 151
  • 1
  • If the solidus is so far away form the liquidus, you will never be able to really know the temperature of your system. At 573°C, the first drop of liquid appears. But the alloy is not yet liquid. You will have to heat it to 632°C to get a clear liquid. So the difference between the appearance of your meal at 590°C and 620°C is not significant. – Maurice Mar 04 '22 at 17:35
5

Based on a search on Matweb, BK7 glass meets your requirements and is close to the middle of your range (559°C melting point).

It's available in small quantities on eBay for reasonable prices.

If you're looking for something with a sharp melting point (for example as a calibration point for a thermocouple or RTD) you don't want a glass though.

Spehro Pefhany
  • 161
  • 3
  • I found out that h-k9l(chinese version) is the equivalent to bk7 glass.Does the melting point of h-k9l the same as bk7?(557 °C) – xchcui Mar 12 '22 at 17:24