Abstract The quaternary compound silicon aluminum oxynitride having a hexagonal phenacite crystal structure is described. The quaternary compound is formed by reacting silicon oxynitride with an appreciable percentage of aluminum. The percent of the product which is converted to the hexagonal quaternary compound is believed to be about 6 times the percentage of aluminum in the product, up to about 15 parts Al/100 parts Si2ON2 when the silicon oxynitride in the product is largely converted to cthe hexagonal quaternary compound Si2 xAlxON2. As more aluminum is added, the relative proportions of aluminum and silicon in the compound seem to change until the formula SiAlON2 is reached at which point no additional aluminum can be accommodated in the crystal lattice. When the mixture is hot processed, the product has high strength and less than about 1 percent porosity. The process of making this novel product is also described.
A dense product consisting predominantly of (a) a quaternary compound of silicon, aluminum, oxygen and nitrogen having the approximate formula Si2 xAlxON2 and the hexagonal phenacite structure, and (b) an amount of silicon, in the form of free silicon or combined silicon, at least equal to the weight of aluminum in the quaternary compound.
Claim 2
Dependent Claim
43 words
A dense product consisting predominantly of the quaternary compound of silicon, aluminum, oxygen and nitrogen, having the approximate formula SiAlON2, and silicon, in the form of free silicon or combined silicon, at least equal to the weight of aluminum in the quaternary compound.
Claim 3
Dependent Claim
15 words
The product of claim 1 wherein the silicon is in the form of free silicon.
Claim 4
Dependent Claim
26 words
A dense product consisting predominantly of the quaternary compound of silicon, aluminum, oxygen and nitrogen having the approximate formula Si2 xAlxON2 and a hexagonal phenacite structure.
Claim 5
Dependent Claim
22 words
A dense product consisting predominantly of silicon carbide and the reaction product of aluminum and silicon oxynitride having a hexagonal phenacite structure.
Claim 6
Dependent Claim
31 words
A dense product consisting predominantly of a quaternary compound of silicon, aluminum, oxygen and nitrogen having a hexagonal phenacite structure and having the following d spacings as measured by X-ray diffractometry:
Claim 7
Dependent Claim
49 words
A process of forming a dense refractory producT which comprises adding aluminum powder to silicon oxynitride powder thoroughly mixing said powders and reacting a compacted mass of the mixture for a sufficient time to cause a substantial portion of said aluminum to be completely reacted with the silicon oxynitride.
Claim 8
Dependent Claim
27 words
The process of claim 8 wherein the silicon which is a by-product of the aluminum plus silicon oxynitride reaction is reacted with carbon to form silicon carbide.