The invention discloses a composite carbon barrier
coating for a
polycrystalline silicon ingot furnace, which is used to coat the surface of a carbon material device in the
ingot furnace to prevent carbon
pollution, and is characterized in that: the composite carbon barrier
coating includes
coating A first coating composed of
metal tungsten or
metal molybdenum coated on the surface of the device, and a second coating coated on the first coating, the second coating is a
silicon nitride layer or a
silicon nitride layer In the laminated layer formed with the
silicon oxide layer, the thickness of the first coating is 0.02-300 microns, and the thickness of the second coating is 0.02-300 microns. The invention also discloses a method for preparing the composite carbon barrier coating; at the same time, the invention also discloses a
graphite guard plate and a polysilicon
ingot furnace comprising the composite carbon barrier coating. The present invention eliminates the generation of
carbon monoxide by coating the composite carbon
barrier layer on the surface of the carbon material device in the polycrystalline ingot furnace, thereby reducing the impurities in the ingot polysilicon and the dislocations derived from the impurities, improving the
crystal quality, and further Improve the conversion efficiency of solar cells.