Method of making moisture resistant aluminum nitride powder and powder produced thereby
AssigneeThe Dow Chemical Company
InventorKevin E. Howard
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Abstract
A method for making a moisture-resistant aluminum nitride-containing powder which includes (a) coating a layer of silicate onto aluminum nitride-containing powder having aluminum nitride on at least a portion of its surface and (b) heat-treating the coated aluminum nitride-containing powder at a temperature of from about 350.degree. to about 1000.degree. C. for a period of time sufficient to cause the silicate to react with the surface aluminum nitride thereby forming a layer of Si-Al-O-N bonded to the surface aluminum nitride. The silicate has alkyl or alkoxyalkyl radicals attached thereto. The method yields a moisture- resistant aluminum nitride-containing powder having a layer of Si-Al-O-N reaction-bonded to the surface aluminum nitride.
Claims17
A method for making a moisture-resistant aluminum nitride-containing powder, comprising:
- (a) coating a layer of a silicate onto aluminum nitride-containing powder having aluminum nitride on at least a portion of its surface, the silicate having substituents thereon selected from the group consisting of alkyl and alkoxyalkyl radicals, and
- (b) heat-treating the coated aluminum nitride-containing powder at a temperature of from about 350.degree. to about 1000.degree. C. for a period of time sufficient to cause the silicate to react with the surface aluminum nitride thereby forming treated aluminum nitride-containing powder having a layer of Si--Al--O--N bonded to the surface aluminum nitride.
The method of claim wherein the heat-treating step is performed for a period from about 10 minutes to about 12 hours.
The method of claim wherein the heat-treating step is performed for a period from about 1 hour to about 2 hours.
A method for making a moisture-resistant aluminum nitride powder, comprising:
- (a) coating a layer of a silicate onto aluminum nitride powder by
- (i) dispersing the aluminum nitride powder in a first alkyl alcohol having from 1 to 4 carbon atoms, inclusive, to form a dispersion, and
- (ii) dissolving into the dispersion, in the following order:
- (A) a solution of the silicate and a second alkyl alcohol having from 1 to 4 carbon atoms, inclusive, the silicate having substituents thereon selected from the group consisting of alkyl and alkoxyalkyl radicals, the silicate being employed in an amount from greater than about 1 to about 150 weight percent based on the weight of the aluminum nitride powder, the first and second alkyl alcohols being employed in an amount from about 50 to about 300 volume percent based on the volume of the aluminum nitride powder,
- (B) water being employed in an amount from about 100 to about 400 weight percent based on the weight of the silicate, and
- (C) a hydrolysis catalyst selected from the group consisting of organic acids selected from the group consisting of acetic acid, formic acid, and propionic acid, inorganic acids selected from the group consisting of hydrochloric acid and sulfuric acid, and bases selected from the group consisting of sodium hydroxide, potassium hydroxide, and ammonium hydroxide, the hydrolysis catalyst being employed in an amount from about 10 to about 75 weight percent based on the weight of the water,
- the aluminum nitride powder, the alkyl alcohols, the silicate, the water, and the hydrolysis catalyst forming a dispersion-solution,
- (b) allowing the aluminum nitride powder to contact the remaining components in the dispersion-solution for at least 5 minutes,
- (c) drying the dispersion-solution to form coated aluminum nitride powder, and
- (d) heat-treating the coated aluminum nitride powder at a temperature of from about 350.degree. to about 1000.degree. C. for a period of time sufficient to cause the silicate to react with the aluminum nitride powder thereby forming a layer of Si--Al--O--N bonded to the aluminum nitride powder.
Dependencies are inferred from the claim text.