Code

A

B

C

Estimated Weight (g)

KC1

40

32

28

26

KC2

40

32

28

30

KC4 (flared)

44

32

28

43

KC7

40

32

32

28

KC8

40

32

32

33

Code

A

B

C

Estimated Weight (g)

KM1

30/32

6

39

18 or 30

KM2

31/33

6

41

19 or 32

KM3

32/34

6

41

21 or 36

KM4

32/38

6

45

22 or 36

KM5

35/37

6

44

25 or 40

KM8

37/40

6

49

28 or 48

KM6

38/41

6

49

29 or 48

KM7

40/42

6

49

34 or 48

KM9

30/32

6

39

18 or 30

Crucible Material

Melting Point (°C)

Max. Service Temp. (°C)

Relative Cost

Key Characteristics & Typical Applications

Nickel (Ni)

1,455

≤ 700

Medium

Excellent alkali resistance. Suitable for fusing with sodium hydroxide, sodium peroxide, etc. Oxidizes easily in air; not for igniting and weighing precipitates.

Silver (Ag)

960

≤ 750

High

Low melting point. Resists potassium/sodium hydroxide attack. Avoid sulfur-containing substances and concentrated acids. Not suitable for weighing precipitates.

Gold (Au)

1,063

≤ 700

High

Excellent corrosion resistance. Can replace platinum for hydrofluoric acid or alkali hydroxide treatments. Low service temperature due to its low melting point.

Platinum (Pt)

1,774

Long-term: 1,200

Expensive

Extremely stable chemical properties. Resistant to hydrofluoric acid and molten carbonates. Ideal for precise ignition/weighing of precipitates and hydrofluoric acid digestions.

Molybdenum (Mo)

2,610

2,000 (Inert/Vacuum)

High

Superior high-temperature strength. Good oxidation resistance. Used for sapphire crystal growth, rare-earth metal smelting, and vacuum deposition.

Niobium (Nb)

2,468

1,200-1,800 (Est.)

High

High melting point and good corrosion resistance. Typically used in high-temperature vacuum or inert atmosphere environments.

Tungsten (W)

3,370

2,200-2,500 (Est.)

Very High

Highest melting point of all metals. Suitable for the most extreme temperatures. Brittle, difficult to machine, and generally more expensive than molybdenum.

Rhenium (Re)

3,180

2,300-2,800 (Est.)

Extremely Expensive

Very high melting point and good strength. Its extreme cost limits use to highly specialized research or applications where its unique properties are critical.

Iridium (Ir)

2,446

2,000-2,300 (Est.)

Extremely Expensive

One of the few metals that remains stable in air at very high temperatures. Used for ultra-high temperature experiments under oxidizing conditions.