Method for using boronizing reaction gases as a protective atmosphere during boronizing, and reaction gas neutralizing treatment

A process comprising:

• placing a boronizing powder composition comprising 2.0 to 4.0 wt % of a boron source selected from B4C, amorphous boron, calcium hexaboride, Borax or mixtures thereof;
• 2.5 to 10.0 wt % of an activator selected from KBF4, ammonia chloride, cryolite, sodium fluoride, ammonium bifluoride, potassium fluoride, calcium fluoride, or mixtures thereof;
• 61.0 to 83.5 wt % of a diluent selected from SiC, alumina or mixtures thereof;
• and 12.0 to 25.0 wt % of a sintering reduction agent selected carbon black, graphite or mixtures thereof, based on the total weight of the boron source, activator, diluent, and sintering reduction agent in the interior of a metal pipe comprising a first end, a second end, an inside surface and an outside surface;
• heating the pipe in a vessel having an interior, to a boriding temperature, thereby forming spent boronizing reaction gases selected from at least one of hydrofluoric acid, fluorine, hydrochloric acid, chlorine, BF3, BCI3, KF, NaF, or mixtures thereof, and a borided layer on the inside surface;
• and
• flowing the spent boronizing reaction gases from the interior of the metal pipe into a reaction chamber, wherein the reactor chamber is positioned inside or outside the furnace.

A process comprising:

• placing a boronizing powder composition in the interior of a metal pipe comprising a first end, a second end, an inside surface and an outside surface;
• heating the pipe in a vessel having an interior, to a temperature from 1400° F. to 1900° F., thereby forming spent boronizing reaction gases and a borided layer on the inside surface, the interior of the vessel having an air atmosphere, and the reaction gases being selected from at least one of hydrofluoric acid, fluorine, hydrochloric acid, chlorine, BF3,BCI3, KF, NaF, or mixtures thereof,
• wherein the air atmosphere of the vessel surrounds the outside surface of the metal pipe;
• flowing the spent boronizing reaction gases into the air atmosphere surrounding the outside surface of the pipe, thereby forming an oxygen-depleted atmosphere stream having an oxygen level of less than 5.0 vol %;
• and
• flowing the oxygen-depleted atmosphere stream to a reaction chamber.

A process comprising:

• placing boronizing powder comprising 2.0 to 4.0 wt % of a boron source selected from B4C, amorphous boron, calcium hexaboride, Borax or mixtures thereof;
• 2.5 to 10.0 wt % of an activator selected from KBF4, ammonia chloride, cryolite, sodium fluoride, ammonium bifluoride, potassium fluoride, calcium fluoride, or mixtures thereof;
• 61.0 to 83.5 wt % of a diluent selected from SiC, alumina or mixtures thereof;
• and 12.0 to 25.0 wt % of a sintering reduction agent selected carbon black, graphite or mixtures thereof, based on the total weight of the boron source, activator, diluent, and sintering reduction agent and a metal workpiece in a first container;
• boronizing the metal workpiece in a furnace, thereby forming spent boronizing gases;
• and
• flowing the spent boronizing gases through absorbent material selected from solid Ca(OH)2, CaO, CaCO3, soda glass, blast furnace slag, Portland cement, sodium hydroxide, soda lime, sodium bicarbonate, limestone, alumina, or mixtures thereof prior to release into the furnace or the environment.