A quartz crucible with lid (also known as a fused silica crucible with cover or high-temperature quartz crucible with Lid) is a high-purity fused silica container engineered for precise sample containment in extreme thermal environments. It is primarily used for volatile matter analysis, ashing, calcination, and high-temperature chemical processing where contamination control and accurate mass measurement are critical. The included matching lid prevents atmospheric contamination, reduces sample loss during heating, and enables accurate determination of volatile content in materials ranging from coal and coke to advanced ceramics and specialty metals.
Key Functions & Typical Applications
This quartz crucible with lid is designed to meet the rigorous demands of laboratories and industrial high-temperature processes:
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Volatile Matter Testing: A tight-fitting lid is essential for standardized volatile matter determination in coal, coke, and biomass materials. The lid prevents oxygen ingress and ensures the measured mass loss reflects only the volatile components rather than combustion or evaporation.
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Ashing and Ignition: Used in muffle furnaces for sample ashing and gravimetric analysis. The lid helps contain low-density powders and prevents sample loss due to air currents during heating.
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Calcination and Sintering: Ideal for high-temperature calcination of ceramic powders, catalyst precursors, and specialty chemicals. The crucible‘s low thermal expansion and chemical inertness make it suitable for extended heating cycles.
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Precious Metal and Alloy Melting: Commonly employed in jewelry, dental laboratories, and metallurgical research for melting and refining gold, silver, platinum, and specialty alloys. The high-purity SiO₂ construction ensures no cross-contamination of melts.
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Semiconductor and Crystal Growth: Used in Czochralski (CZ) silicon crystal pulling, compound semiconductor processing, and advanced material synthesis where ultra-high purity (>99.99% SiO₂) and dimensional stability at temperatures up to 1650°C are required.
Material, Specifications & Performance Characteristics
Our quartz crucible with lid is manufactured from high-purity fused quartz (amorphous SiO₂), a material renowned for its exceptional thermal, chemical, and mechanical properties.
Material Grades Available
| Grade | SiO₂ Purity | Appearance | Best Suited For |
|---|---|---|---|
| Standard High-Purity | ≥99.9% | Translucent to Opaque (White) | General laboratory use, ashing, calcination, metal melting |
| Semiconductor/Ultra-High Purity | ≥99.99% | Transparent (Clear) | Crystal growth, semiconductor processing, trace element analysis |
Fused quartz exhibits a softening point of approximately 1680–1730°C, with recommended continuous operating temperatures up to 1200°C and short-term use up to 1350–1450°C.
Why the Lid Matters
The matching quartz lid is a critical component of this product, not an optional accessory. Key lid functions include:
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Contamination Prevention: Prevents atmospheric particulates and airborne contaminants from entering the crucible during heating and cooling.
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Volatile Loss Reduction: Minimizes sample loss due to evaporation or splashing, enabling accurate gravimetric analysis.
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Atmosphere Control: Creates a semi-sealed environment that helps control oxidation/reduction conditions during thermal treatment.
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Thermal Uniformity: Promotes even temperature distribution across the sample and reduces radiative heat loss.
Technical Data Table
Physical and Thermal Properties
| Property | Value | Remarks |
|---|---|---|
| SiO₂ Purity | ≥99.9% (Standard Grade); ≥99.99% (Ultra-High Purity Grade) | Verified via ICP-MS analysis |
| Density | 2.19–2.21 g/cm³ | Higher than typical ceramic crucibles |
| Porosity | <1% (High-density fused silica ceramic) | Smooth, low-absorption surface |
| Softening Point | ~1680–1730°C | Material begins to soften |
| Continuous Operating Temperature | ≤1200°C | Recommended for long-term use |
| Short-Term Peak Temperature | ≤1350–1450°C | Intermittent exposure only |
| Maximum Use Temperature | 1650°C | Brief exposure; devitrification risk increases |
| Thermal Expansion Coefficient (CTE) | ≤0.54–0.6×10⁻⁶ /°C | Extremely low; excellent thermal shock resistance |
| Thermal Shock Resistance | 1100°C → 25°C water quench, no cracking for 10+ cycles | Superior to most ceramic crucibles |
| Thermal Conductivity @ 20°C | ~1.4 W/m·K | Low thermal conductivity |
| Compressive Strength | ≥50 MPa (room temperature) | Sufficient for routine handling |
Chemical Compatibility
Quartz crucibles with Lid are chemically inert to most substances, with important exceptions noted below:
| Compatible With | Incompatible With (Avoid Contact) |
|---|---|
| Most acids (HCl, HNO₃, H₂SO₄) | Hydrofluoric acid (HF) – reacts readily at all temperatures |
| Most organic solvents | Phosphoric acid (H₃PO₄) above 200°C |
| Most metals and metal oxides (at moderate temperatures) | Strong alkalis and basic oxides at elevated temperatures (>800°C) |
| Inert gases (N₂, Ar, He) | Certain reactive metals at high temperatures (e.g., molten aluminum, magnesium) |
Standard Sizes & Dimensions
We offer a comprehensive range of standard quartz crucible with lid sizes. Each crucible is supplied with a precisely matched lid to ensure optimal fit and performance.
| Outer Diameter (mm) | Height (mm) | Approximate Capacity (ml) | Lid Included |
|---|---|---|---|
| 25 | 28 | 5 | ✓ |
| 29 | 34 | 10 | ✓ |
| 32 | 37 | 15 | ✓ |
| 36 | 41 | 20 | ✓ |
| 38 | 45 | 30 | ✓ |
| 48 | 52 | 50 | ✓ |
| 58 | 68 | 100 | ✓ |
| 67 | 78 | 150 | ✓ |
| 73 | 86 | 200 | ✓ |
| 83 | 106 | 300 | ✓ |
| 91 | 108 | 400 | ✓ |
| 100 | 118 | 500 | ✓ |
| 112 | 132 | 750 | ✓ |
| 125 | 146 | 1000 | ✓ |
Note: Dimensions are nominal and may vary slightly due to manufacturing tolerances. The lid dimensions are matched to each crucible size for a proper fit. Custom sizes, non-standard capacities, and specialty shapes (cylindrical, tapered, deep-well) are available upon request.
Quality Standards & Certifications
Our fused silica crucible with cover products are manufactured under a rigorous quality management system and conform to internationally recognized standards:
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ISO 9001:2015: Certified quality management system ensuring consistent manufacturing processes and product traceability.
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ASTM C751: Standard specification for fused silica glass, covering physical and chemical properties relevant to crucible applications.
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ASTM C1410: Standard specification for high-purity fused silica, outlining criteria for purity, density, and mechanical strength in industrial applications.
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SEMI Standards: For semiconductor-grade crucibles, compliance with SEMI specifications for dimensional tolerances and purity levels.
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ISO 17139: International standard for fused silica glassware, defining requirements for materials, dimensions, and performance including thermal shock and chemical resistance.
Inspection & Quality Control
Each high-temperature quartz crucible with lid undergoes comprehensive inspection before shipment to ensure reliable performance in demanding applications:
| Inspection Item | Method | Acceptance Criteria |
|---|---|---|
| Dimensional Accuracy | Coordinate measuring machine (CMM), laser profilometry | Within specified tolerances; consistent wall thickness |
| Surface Quality | Optical microscopy, visual inspection | Smooth surface; no scratches, pits, or residual particles |
| Internal Defects | Ultrasonic testing, X-ray imaging | No bubbles, inclusions, or microcracks exceeding specification limits |
| Purity Verification | ICP-MS (Inductively Coupled Plasma Mass Spectrometry) | SiO₂ ≥99.9% or ≥99.99% as ordered; trace metals within ppm limits |
| Thermal Shock Validation | Water quench testing | 1100°C → 25°C water, no cracking for minimum 10 cycles |
| Lid Fit & Clearance | Mechanical fit test | Horizontal clearance between lid and crucible ≤0.5 mm |
Test Reports Available Upon Request: Certificates of Analysis (CoA) including purity verification and dimensional inspection reports can be provided with each order. Please indicate your documentation requirements when submitting an inquiry.
