Grown diamonds are artificially created in a laboratory to simulate the process of diamond formation in nature. This process is often called Chemical Vapor Deposition (CVD) or High Pressure High Temperature (HPHT) method. Here is a brief description of the two main synthetic diamond processes:
Chemical Vapor Deposition (CVD) Method:
Raw gas: The CVD method uses a carbon source gas (usually methane) and hydrogen as the raw gas, and a carbon-containing substrate (usually natural diamond).
Reaction chamber: The raw material gas is introduced into the high-temperature and high-pressure reaction chamber.
Atomic decomposition: At high temperatures, methane decomposes into carbon atoms, which deposit on the base plate, gradually forming a diamond lattice.
Growth: The diamond lattice gradually grows, layer by layer, and eventually forms a complete diamond.
Control parameters: Control parameters such as temperature, pressure, gas flow rate and time to ensure the growth and quality of diamonds.
High pressure and high temperature synthesis (HPHT) method:
Feedstock: The HPHT method uses high-quality carbon feedstock (usually diamond chips or graphite).
Pressure and Temperature: The raw materials are placed in an environment of high temperature and pressure, usually at pressures of several gigapascals (GPa) and temperatures of several thousand degrees Celsius.
Atomic rearrangement: Under these extreme conditions, the carbon material rearranges into a diamond lattice structure.
Forming: Diamond crystals are gradually formed in an environment of high temperature and pressure, and are maintained under these conditions until they reach the desired size and quality.
Regardless of whether it is CVD or HPHT method, the final synthetic diamond needs to undergo subsequent cutting, grinding and polishing process steps to make diamonds for jewelry.
These synthetic diamonds can often have similar physical and chemical properties to natural diamonds, but their mass, size and shape can be precisely controlled through a synthetic process, giving them unique advantages in some applications.