Abstract: A process for preparing a nitridable silicon-containing material, which process includes comminuting a slurry of silicon powder, and water, the comminuting performed to cause substantial chemical reaction between the silicon and the water. Reducing the water content of the reacted slurry forms a processable mass. In another embodiment, desired additives such as at least one nitriding agent may be added to aid any nitridation or other processing which may be performed thereafter.

Abstract: A process for preparing an alpha-phase silicon nitride material and thereafter sintering to a densified beta-phase silicon nitride material is disclosed which includes comminuting a slurry including a mixture of silicon powder, water, and at least one densification aid to aid in later densifying of the silicon nitride material, the comminuting being performed to form fresh, non-oxidized surfaces on the silicon powder and to allow substantial chemical reaction between the silicon and the water, reducing the water content of the reacted slurry to a degree sufficient to form a resultant dry mass, nitriding the dry mass by exposure to a sufficient amount of a nitriding gas including at least nitrogen at a sufficient temperature for a sufficient length of time to form a mass of substantially alpha-phase silicon nitride, and sintering the resultant silicon nitride mass at a sintering temperature of from about 1450.degree. C. to about 2100.degree. C.

Abstract: A process for making silicon powder or articles of manufacture such as an internal combustion engine valve by comminuting a homogeneous water-base slurry of silicon powder and at least one nitriding agent and permitting the slurry to chemically react for a time sufficient to enable the chemical reaction to substantially reach completion, then reducing the water content sufficiently to form a powder or an article and thence nitriding the article or powder by continuously varying the temperature over the range of 1000.degree. C. to 1450.degree. C. using a nitriding gas comprising nitrogen, hydrogen and helium and maintaining a constant nitriding gas composition throughout the nitriding cycle.

Abstract: A process for preparing a nitridable silicon-containing material, which process includes (a) comminuting a slurry of silicon powder, water, at least one densification aid, including Al.sub.2 O.sub.3, and another densification aid, the comminuting performed to cause substantial chemical reaction between the silicon and the water; and (b) reducing the water content of the reacted slurry to form a dry mass. In another embodiment, at least one nitriding agent may be added to aid any nitridation which may be performed.

Abstract: A process for nitriding materials containing silicon to form a silicon nitride material predominantly in the alpha phase is disclosed which includes nitriding the silicon-containing material by subjecting it to a nitriding atmosphere containing at least nitrogen gas in combination with at least one other nitriding gas while keeping the composition of the nitriding atmosphere substantially constant by maintaining a substantially constant partial pressure of nitrogen gas during the nitriding, even though nitrogen is being consumed during the nitriding step to form the silicon nitride.

Abstract: A procedure for qualifying a proposed synthetic lubricant includes: (1) compatibility testing the proposed lubricant with previously approved synthetic lubricants; (2) stability testing the lubricant for thermal oxidation by testing the lubricant in a heated gear box; (3) corrosion testing the proposed lubricant by a copper strip tarnish test; (4) field testing the proposed lubricant to evaluate the ability of the lubricant to withstand extended drain intervals while still performing its function; and analyzing all of the results of those tests. In another embodiment, the lubricant furthermore undergoes a seal life test to evaluate the appearance of various covers and seals for degradation due to long term exposure to the lubricant.

Abstract: A process for preparing an alpha-phase silicon nitride material and thereafter converting to non-densified beta-phase silicon nitride material includes comminuting a slurry including a mixture of silicon powder and water to form non-oxidized surfaces on the silicon powder and to allow chemical reaction between the silicon and water, reducing the water content of the reacted slurry to a degree sufficient to form a resultant dry mass, nitriding the dry mass by exposure to a nitriding gas including at least nitrogen to form a mass of alpha-phase silicon nitride, and converting the resultant silicon nitride mass at a conversion temperature of from about 1450.degree. C. to about 2100.degree. C. to convert the silicon nitride from an alpha-phase material to a non-densified beta phase silicon nitride material.

Abstract: An enclosable vessel for containing a silicon nitride article during sintering in a furnace to protect the silicon nitride article from thermal decomposition and contamination reactions with furnace materials comprises a closeable walled container formed of a reaction bonded silicon nitride material having an opening to allow interior placement of the silicon nitride article within the walled container. This box is used to replace silicon nitride powder which has heretofore been used to cover silicon nitride articles during sintering.

Abstract: A body of sintered silicon nitride contains new non-glassy phases which produce significant X-ray diffraction peaks at 2-theta diffraction angles corresponding to d-spacings of about 2.86 Angstroms and 3.59 Angstroms and process for making same, which process includes (a) comminuting a slurry of a silicon-containing powder, water, about 0.1 to 5 volume percent of Fe.sub.2 O.sub.3, about 0.1 to 5 volume percent Al.sub.2 O.sub.3, and about 0.5 to 10 volume percent CeO.sub.2, wherein all volume percents are based on the volume of the resultant silicon nitride, the composition of the slurry being such that about a 4 to 12 volume percent liquid phase is achieved during sintering; (b) reducing the water content of the reacted slurry to form a dry mass; (c) nitriding the dry mass by exposure to a nitriding gas at an elevated temperature to form silicon nitride; and (d) sintering the silicon nitride at about 1450.degree.-2100.degree. C.

Abstract: A process for preparing a nitridable silicon-containing material, which process includes (a) comminuting a slurry of silicon powder, water, at least one densification aid, including Al.sub.2 O.sub.3, and another densification aid, the comminuting performed to cause substantial chemical reaction between the silicon and the water; and (b) reducing the water content of the reacted slurry to form a dry mass. In another embodiment, at least one nitriding agent may be added to aid any nitridation which may be performed.