Pyrolytic Graphite Coated Crucible

PG Coated Carbon Crucible is a specially processed crucible product. It is commonly used for evaporation, melting and deposition of materials at high temperatures and in vacuum environments, and plays a key role in vacuum evaporation processes in particular. The core design is to utilize the excellent physical properties of Pyrolytic Graphite to coat the inner wall or the entire surface of the crucible, thus enhancing the crucible's high temperature resistance, chemical inertness and thermal homogeneity.

Structural Characteristics:

Matrix Material and Coating Structure:

Susceptor Material: Our graphite crucibles are made of graphite material as the substrate to ensure the overall mechanical strength and heat resistance.

Pyrolytic Carbon ( PyC ) Coating: A layer of high-purity, highly crystalline pyrolytic graphite is uniformly deposited on the inside or outside of the crucible by means of the Chemical Vapor Deposition (CVD) process. The thickness of the coating is 30 µm by default. The coating is layered and highly anisotropic between layers in the direction of crystal growth. The purity of the coating exceeds 99.999% and the impurity content is less than 10 ppm, which makes it particularly suitable for processes with stringent purity requirements. We also support customized coating thicknesses according to your needs.

Sealing and erosion resistance:

Our coatings have a very low porosity and a smooth surface (e.g. mirror-polished) and therefore protect the substrate against chemical reactions between the molten material and the crucible base material at high temperatures, thus prolonging the service life of the crucible.

In a vacuum and inert atmosphere, pyrolytic graphite exhibits excellent erosion resistance, ensuring that the material will not be contaminated by chemical reaction with the vessel or by permeation in a high temperature environment.

PG Coated Carbon Crucible Packaging

Our Pyrolytic Graphite Coated Crucible will be co-packed with high density wooden crates and a large amount of foam, and carefully handled during storage and transportation to maintain the original quality of our products. We look forward to your further inquiry!

Specific role in vacuum evaporation:

1. Uniform heating and evaporation control:

The pyrolytic graphite coated on the inner wall of the crucible can provide good thermal conductivity to ensure uniform temperature distribution during the heating process, so that the material to be evaporated can evaporate stably and uniformly in the vacuum.

2. Prevent chemical reaction and contamination:

The high thermal conductivity of pyrolytic graphite ensures that the evaporated material (e.g. aluminum) is heated uniformly, which improves the coating quality; meanwhile, the chemical inertness of PG prevents the molten metal from reacting with the crucible, which avoids the generation of impurities as well as the potential contamination.

3. Improve process stability and repeatability:

Due to its excellent high temperature resistance and low thermal expansion characteristics, the use of PG Coated Carbon Crucible can significantly reduce process fluctuations caused by temperature fluctuations or localized overheating, thus improving product consistency. For example, in electron beam evaporation, Graphite crucibles with PG coating can withstand the bombardment of high-energy electron beams, maintaining structural stability and preventing the material from volatilizing and getting out of control.

4. Extend the service life of equipment:

The low porosity and high corrosion resistance of Pyrolytic Graphite coating effectively reduces material erosion. For example, in vacuum aluminizing process, Pyrolytic Graphite Crucible can be used continuously for 24-52 hours, which greatly reduces the frequency of replacement and production cost.