Pressure assisted melt infiltration

A method of melt infiltrating a fiber preform comprising:

• providing the fiber preform inside of a pressure vessel, the pressure vessel projecting into a molten material contained in a crucible, the pressure vessel having an opening located below a surface of the molten material through which the molten material enters the pressure vessel, wherein an end of the fiber preform contacts the molten material within the pressure vessel, the pressure vessel and crucible located in a furnace;
• pulling the molten material within the pressure vessel vertically higher in the pressure vessel to cover the fiber preform with the molten material by increasing a first pressure at a first port of the furnace so the first pressure is higher than a second pressure at a second port of the pressure vessel and higher than the vapor pressure of the molten material, the second port located above the molten material in the pressure vessel;
• increasing the second pressure at the second port and the first pressure at the first port while the fiber preform is covered with the molten material, wherein the first pressure and the second pressure are increased to at least an ambient atmospheric pressure to a matching pressure;
• and
• infiltrating the fiber preform with the molten material to react with a portion of the fiber preform and to form a reaction product within the fiber preform.