Rectangular Alumina Crucibles with Lid & Custom Sizes

Alumina Rectangular Crucibles Applications

Usage Instructions for Rectangular Alumina Crucible

• Use

  1. Inspection before use
  a.Check for chips, cracks, or surface defects before each cycle.
  b.Pre-dry crucible at 110–150 °C for 1–2 hours to remove moisture.

  2. Loading sample
  a.Distribute material evenly across the flat base; avoid uneven piling.
  b.Do not exceed 70–80% of total ml capacity to prevent overflow.
  c.For volatile samples, use a lid or cover to minimize loss.

  3. Operation during heating
  a.Increase temperature gradually; recommended ramp rate: ≤ 5–10 °C/min for cycles above 1000 °C.
  b.Avoid sudden cooling; allow crucible to cool inside the furnace chamber whenever possible.

  4. Using lids
  a.Place lids loosely to allow controlled gas exchange.
  b.For atmosphere-controlled tests, confirm lid fit according to protocol requirements.

• Storage

  a.Store crucibles in a dry, dust-free environment with stable room temperature.
  b.Use foam, tissue, or felt separators between crucibles to prevent edge abrasion.
  c.Keep standard sizes grouped and labeled (e.g., 25 ml, 100 ml, 250 ml) for easier selection.
  d.Avoid stacking more than 3–4 layers to reduce risk of edge cracking.

• Cleaning

  1. Cooling
  a. Always allow natural cooling to room temperature before handling.
  b. Avoid sudden immersion in water or solvents on hot crucibles.

  2. Residue removal
  a.Gently brush off loose powder or ash with a soft ceramic brush.
  b.For stubborn residues, soak in dilute acid or alkali solutions compatible with alumina, then rinse and dry.

  3. Re-drying
  a.After wet cleaning, re-dry crucibles at 110–150 °C for 1–2 hours before reuse.
  b.Store only when fully dry to prevent micro-cracks from moisture exposure.

• Common Misuse & Fix

  a. Thermal shock (cracks)→ Use slower heating/cooling ramps (≤ 5–10 °C/min) or select thicker wall crucibles for aggressive cycles.
  b.Edge chipping→ Order crucibles with larger corner radius (R ≥ 2 mm) or use alumina setter plates during loading/unloading.
  c.Residue contamination→ Dedicate crucibles for specific chemistries (e.g., oxides, salts, alloys). Clean thoroughly between series to avoid cross-contamination.
  d.Overloading→ Keep sample volume below 80% of crucible ml capacity; overfilled crucibles increase spill risk and shorten lifespan.
  e.Improper lid use→ Do not seal lids tightly unless required by controlled-atmosphere testing; otherwise, pressure buildup may cause cracking.

Alumina Crucibles Rectangular FAQ

1. Q: What is a rectangular alumina crucible used for?
   A: A rectangular alumina crucible is used for laboratory heating, calcination, sintering, ashing, and clean material holding where a flat base and efficient furnace loading are needed.
2. Q: What purity options are available?
   A: Common options include 99%, 99.6%, and 99.7% Al₂O₃. Higher purity can be selected when contamination control or higher process temperature is more important.
3. Q: Can I order a rectangular alumina crucible with a lid?
   A: Yes. Flat, recessed, or custom lids can be supplied to reduce volatilization, protect samples, or support controlled-atmosphere heating.
4. Q: Can the size be customized?
   A: Yes. Length, width, height, capacity, wall thickness, corner radius, lid fit, and markings can be customized according to drawings or furnace space.
5. Q: What temperature can it withstand?
   A: Rectangular alumina crucibles are often used up to about 1600–1730°C, depending on alumina purity, geometry, load, atmosphere, and heating cycle.
6. Q: Is it suitable for metal melting?
   A:  It can be used with many metals and alloys, but compatibility should be checked for aggressive molten media, strong alkalis, HF, or reactive chemistries.
7. Q: How can I reduce cracking during use?
   A: Pre-dry the crucible, avoid rapid heating and cooling, do not overload it, and select suitable wall thickness and corner radius for repeated cycles.
8. Q: What information should I provide for a quotation?
   A: Please provide capacity, length, width, height, purity, lid requirement, working temperature, sample chemistry, quantity, and drawings if available.