Aluminum Based Metal Powders and Methods of Their Production

Abstract

Aluminum-based metallic powders, along with their methods of production and formation, are provided. The Al-based metallic powders are formed with an increased amount of oxygen within at least a portion of the particles of the powder. The Al-based metallic powders show improved flowability.

What is claimed: 
     
         1 . A method of forming a metal powder of Al-based metallic particles, comprising:
 supplying an Al-based source metal into a heat zone of an atomizer such that Al-based metallic particles are formed in a plasma field, wherein the Al-based metallic source material comprises at least 50% by weight aluminum and has an initial oxygen concentration; and   supplying oxygen into the atomizer such that a majority of the Al-based metallic particles have a particle oxygen concentration that is greater than the initial oxygen concentration of the Al-based metallic source material.   
     
     
         2 . The method of  claim 1 , wherein the initial oxygen concentration is less than 10 ppm by weight, and wherein the particle oxygen concentration is greater than 30 ppm by weight. 
     
     
         3 . The method of  claim 2 , wherein the particle oxygen concentration is greater than 100 ppm to 1000 ppm by weight. 
     
     
         4 . The method of  claim 3 , wherein the particle oxygen concentration is greater than 300 ppm to 600 ppm by weight. 
     
     
         5 . The method of  claim 1 , wherein the majority of the Al-based metallic particles have a normalized half oxygen concentration that is 50% of a normalized maximum oxygen concentration, wherein the normalized half oxygen concentration is 0.002 min/μm 2  or greater as measured via auger electron spectroscopy. 
     
     
         6 . The method of  claim 1 , wherein the majority of the Al-based metallic particles have a particle size distribution of 10 μm to 45 μm or 45 μm to 106 μm. 
     
     
         7 . The method of  claim 1 , further comprising measuring the particle oxygen concentration with auger electron spectroscopy. 
     
     
         8 . The method of  claim 1 , further comprising heating the Al-based source metal to a temperature in a range from 80% to 85% of a melting point of the Al-based source metal. 
     
     
         9 . The method of  claim 1 , further comprising flowing the Al-based source metal at a mass flow rate of at least 250 inches per minute. 
     
     
         10 . The method of  claim 1 , wherein supplying the oxygen into the atomizer further comprises supplying an oxygen-containing gas including the oxygen at a rate of at least 60 cubic centimeters per minute. 
     
     
         11 . The method of  claim 1 , wherein the atomizer is a plasma torch. 
     
     
         12 . A method of forming a metal powder of Al-based metallic particles, comprising:
 forming Al-based metallic particles in a plasma field of a heat zone of an atomizer from an Al-based metallic source material, wherein the Al-based metallic source material comprises at least 50% by weight aluminum; and   directing oxygen into the atomizer such that oxygen reacts with aluminum on and within the Al-based metallic particles to form aluminum oxides therein, wherein a majority of the Al-based metallic particles comprises a normalized half oxygen concentration that is 50% of a normalized maximum oxygen concentration, wherein the normalized half oxygen concentration is 0.002 min/μm 2  or greater as measured via auger electron spectroscopy, wherein majority of Al-based metallic particles has a particle size distribution of 10 μm to 45 μm, 15 μm to 45 μm, 10 μm to 53 μm, 15 μm to 63 μm, 20 μm to 63 μm, 15 μm to 53 μm, 45 μm to 106 μm, or 25 μm to 45 μm.   
     
     
         13 . The method of  claim 12 , wherein the Al-based metallic source material is supplied to the atomizer at a feed rate of 600 standard liters per minute or greater. 
     
     
         14 . The method of  claim 12 , wherein the oxygen is supplied to the atomizer as an oxygen-containing gas. 
     
     
         15 . The method of  claim 12 , wherein forming the Al-based metallic particles comprises contacting the Al-based metallic source material with an atomization gas and an oxygen-containing gas. 
     
     
         16 . The method of  claim 15 , wherein the Al-based metallic source material is heated prior to contact with the atomizing gas and/or the oxygen-containing gas. 
     
     
         17 . The method of  claim 15 , wherein the Al-based metallic source material is heated to 80% of its melting point or greater prior to contact with the atomizing gas and/or the oxygen-containing gas. 
     
     
         18 . The method of  claim 15 , wherein the oxygen-containing gas comprises O 2 , O 3 , CO 2 , CO, NO, NO 2 , SO 2 , SO 3 , air, water vapor, or mixtures thereof. 
     
     
         19 . The method of  claim 12 , wherein the plasma field is generated via a plasma torch. 
     
     
         20 . The method of  claim 12 , wherein the plasma field is generated via a RF plasma torch, a DC plasma torch, an AC plasma torch, a microwave plasma torch, or a plasma arc generator.