Sapphire Tube

Product Overview
    EFG sapphire tubes and profiles are single-crystal sapphire components directly grown from 4N5 grade high-purity alumina via the Edge-defined Film-fed Growth (EFG) process. Its core principle is to shape the crystal cross-section through customized molybdenum dies: molten alumina climbs along the internal slits of the die to the top by capillary action to form a liquid film. After the seed crystal contacts the liquid film, it is slowly pulled upward, and the melt crystallizes and solidifies continuously along the seed crystal orientation, directly growing long-size single-crystal profiles with exactly the same cross-sectional shape as the die. This process achieves near-net-shape forming, greatly reducing subsequent machining allowance such as cutting and drilling. Its material utilization rate and mass production efficiency are significantly superior to the traditional Kyropoulos solid ingot machining solution. The products fully inherit the intrinsic advantages of single-crystal sapphire: high temperature resistance, high hardness, strong corrosion resistance, high electrical insulation and broad-spectrum light transmission, and feature outstanding long length, thin wall thickness and high cost-effectiveness. Customized structures including straight tubes, stepped tubes, reducing tubes, round rods, thin plates and special-shaped profiles are available. They are cost-effective single-crystal solutions for high-temperature industries, general semiconductor processes, chemical fluid delivery and optical inspection.

Core Technical Features
1.Near-Net-Shape EFG Growth Process
    Customized dies directly shape the crystal cross-section, and the as-grown profiles are close to the finished shape. There is no need for extensive material removal from solid ingots as in the Kyropoulos process. The material utilization rate can reach over 60% (usually less than 20% for Kyropoulos machined tubes), greatly reducing raw material loss and processing costs, and suitable for mass production of standardized products.

2.Long-Length & Thin-Wall Specification Advantage
    Long-size profiles with a length of over 1500mm can be grown in one run, and the minimum wall thickness can be controlled at 0.3mm, perfectly meeting the needs of long-path fluid delivery and long furnace matching. Limited by ingot size, Kyropoulos long tubes require splicing, and thin-wall tube machining involves huge material loss and high cost.

3.High-Purity Single-Crystal Material Base
    The base material is 4N5 grade (≥99.995%) high-purity single-crystal α-Al₂O₃, a monolithic single crystal free of grain boundaries, pores and impurity segregation. Although its crystal integrity is slightly inferior to Kyropoulos-grown ingots, it is far superior to traditional tubes such as polycrystalline alumina ceramics and quartz glass, meeting the performance requirements of most industrial scenarios.

4.Ultra-High Temperature & Thermal Shock Stability
    The material has a melting point of 2050℃ and a long-term working temperature of up to 1600℃ in oxidizing atmosphere. With a low thermal expansion coefficient, it has minimal dimensional deformation at high temperatures and can withstand severe thermal shock without cracking, suitable for thermal scenarios such as tube furnaces, high-temperature sintering and medium-temperature plasma.

5.High Hardness, Wear & Chemical Corrosion Resistance
    With Mohs hardness of Grade 9, it has excellent wear and scratch resistance, and can withstand high-pressure fluid scouring and particle friction. It has extremely strong chemical inertness, resists most strong acids, alkalis and organic solvents at room temperature, and is only slowly corroded by hydrofluoric acid and hot phosphoric acid. Its service life is much longer than quartz and glass tubes.

6.Excellent Electrical Insulation & Optical Performance
    With room-temperature resistivity higher than 10¹⁴ Ω·cm and stable dielectric properties, it provides reliable high-voltage electrical isolation, suitable for RF and high-voltage power scenarios. It has high transmittance in the band from 190nm UV to 4.5μm mid-infrared, meeting light transmission requirements such as fluid observation, optical inspection and ultraviolet reaction.

7.Full-Structure Customization & Precision Machining Capability
    Profiles with various cross-sections such as round, square and special shapes can be customized by replacing dies. Structures including straight tubes, stepped tubes, reducing tubes and grooved tubes are available. Secondary processing such as end-face polishing, inner/outer cylindrical fine grinding, chamfering, precision drilling and metallization sealing can be completed to accurately match equipment installation interfaces.

8.Large-Scale Mass Production & Cost Advantage
    Long-size profiles can be grown in a single run, and multiple finished products can be obtained after cutting and segmentation, leading to high mass production efficiency. Combined with the high material utilization of near-net-shape forming, the overall product cost is significantly lower than similar products processed by the Kyropoulos method, suitable for cost-sensitive, high-volume conventional industrial scenarios.

Standard Specifications

Typical Applications

1. High-temperature industry: Tube furnace liners, high-temperature sintering protection tubes, thermocouple protection sleeves, metallurgical high-temperature delivery tubes, withstanding 1600℃ high temperature and thermal shock for long-term operation, replacing quartz tubes to greatly improve service life
2. General semiconductor field: Medium & low-end plasma gas delivery tubes, process cleaning pipelines, wafer transfer protection sleeves, resistant to moderate-intensity plasma bombardment, with better cost-effectiveness than high-end Kyropoulos semiconductor tubes
3. Chemical fluid field: Highly corrosive fluid delivery tubes, chemical reaction observation tubes, high-purity medium flow pipelines, resistant to most acid and alkali corrosion and ensuring medium purity
4. Optical & inspection field: Optical detection flow cells, ultraviolet reaction tubes, spectrometer sample tubes, laser cavity protection tubes, combining light transmittance and corrosion resistance
5. General industrial field: Wear-resistant shaft sleeves, fluid nozzles, sensor protection sleeves, high-temperature observation window tubes, replacing metals, plastics and ordinary ceramics to greatly extend service life

Quality Control

A full-process quality control system from die preparation to finished product delivery is established, and each product undergoes strict multi-dimensional inspection. Core inspection items include: inner/outer diameter and wall thickness dimensional accuracy inspection, coaxiality and straightness calibration, full-tube visual defect screening (scratches, edge chipping, bubbles, impurities), surface roughness inspection, pressure resistance and air tightness sampling inspection, and optical transmittance verification. Standard test reports can be provided for industrial-grade products, and XRD crystal orientation verification reports can be provided for products with special requirements, ensuring accurate parameters and stable performance to meet the requirements of different grades of industrial scenarios.

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